Elemental Measures - Questions

The Elemental Measures Concept Builder is comprised of 27 questions. The questions are organized into nine Question Groups and spread across three different difficulty levels. The Concept Builder provides students with some elemental book-keeping experience. Students will count the number of atoms of each element on the reactant and the product side of the equation. Then they will determine the mass of each element on both sides of the equation. And they will answer two conceptual follow-up questions about atoms and mass being conserved. There are three levels of difficulty with each level adding an additional element to the reaction. The Apprentice Difficulty Level includes synthesis reactions involving two elements. The Master Difficulty Level includes reactions in which there are three elements in the reactant and product species. And the Wizard Difficulty Level includes reations that involve four elements in the reactant and product species. The questions are shown below.

To complete a level, students must complete both the atomic scale analysis (# of atoms) and the macroscopic scale analysis (mass in grams).  A built-in number pad makes numerical entry very easy on mobile devices. Feedback is immediate and students can correct their incorrect answers. Help is provided for each difficulty level. 

The Physics Classroom grants teachers and other users the right to print these questions for private use. Users are also granted the right to copy the text and modify it for their own use. However, this document should not be uploaded to other servers for distribution to and/or display by others. The Physics Classroom website should remain the only website or server from which the document is distributed or displayed. We also provide a PDF that teachers can use under the same conditions. We have included a link to the PDF near the bottom of this page.

 

Elemental Measures (a.k.a., Stoikheion-metry)

 
Apprentice Difficulty Level
Question Group 1
Question 1
Atomic Scale Analysis:
Consider the reaction  2 H₂    +    O₂    →    2 H₂O .  Count the number of atoms of the elements H and O on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of H: _______                                # atoms of H: ________
# atoms of O: ________                             # atoms of O: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction 2 H₂    +    O₂    →    2 H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements H and O on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of O: ________                            Mass (g) of O: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 
 
 

 
Question 2
Atomic Scale Analysis:
Consider the reaction  N₂    +    3 H₂    →    2 NH₃ .  Count the number of atoms of the elements N and H on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of N: ________                             # atoms of N: ________
# atoms of H: _______                                # atoms of H: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction N₂    +    3 H₂    →    2 NH₃, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements N and H on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of N: ________                            Mass (g) of N: ________
Mass (g) of H: _______                              Mass (g) of H: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 
 
 

 
Question 3
Atomic Scale Analysis:
Consider the reaction  3 Ti    +    2 N₂    →    Ti₃N₄ .  Count the number of atoms of the elements Ti and N on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Ti: _______                               # atoms of HTi ________
# atoms of N: ________                             # atoms of N: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  3 Ti    +    2 N₂    →    Ti₃N₄, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Ti and N on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Ti: _______                              Mass (g) of Ti: ________
Mass (g) of N: ________                            Mass (g) of N: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 
 
 

 
Question Group 2
Question 4
Atomic Scale Analysis:
Consider the reaction  2 Al    +    3 Cl₂    →    2 AlCl₃ .  Count the number of atoms of the elements Al and Cl on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Al: _______                               # atoms of Al: ________
# atoms of Cl: _______                               # atoms of Cl: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  2 Al    +    3 Cl₂    →    2 AlCl₃, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Al and Cl on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Al: _______                              Mass (g) of Al: ________
Mass (g) of Cl: _______                             Mass (g) of Cl: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 
 
 

 
Question 5
Atomic Scale Analysis:
Consider the reaction  2 Al    +    3 Br₂    →    2 AlBr₃ .  Count the number of atoms of the elements Al and Br on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Al: _______                               # atoms of Al: ________
# atoms of Br: _______                              # atoms of Br: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  2 Al    +    3 Br₂    →    2 AlBr₃, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Al and Br on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Al: _______                              Mass (g) of Al: ________
Mass (g) of Br: _______                             Mass (g) of Br: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 
 
 

 
Question 6
Atomic Scale Analysis:
Consider the reaction  2 Al    +    3 I₂    →    2 AlI₃ .  Count the number of atoms of the elements Al and I on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Al: _______                               # atoms of Al: ________
# atoms of I: _______                                 # atoms of I: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  2 Al    +    3 I₂    →    2 AlI₃, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Al and I on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Al: _______                              Mass (g) of Al: ________
Mass (g) of I: _______                                Mass (g) of I: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question Group 3
Question 7
Atomic Scale Analysis:
Consider the reaction  4 Li    +    O₂    →    2 Li₂O .  Count the number of atoms of the elements Li and O on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Li: _______                               # atoms of Li: ________
# atoms of O: _______                               # atoms of O: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  4 Li    +    O₂    →    2 Li₂O , the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Li and O on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Li: _______                              Mass (g) of Li: ________
Mass (g) of O: _______                              Mass (g) of O: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 
 
 

 
Question 8
Atomic Scale Analysis:
Consider the reaction  4 K    +    O₂    →    2 K₂O .  Count the number of atoms of the elements K and O on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of K: _______                                # atoms of K: ________
# atoms of O: _______                               # atoms of O: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  4 K    +    O₂    →    2 K₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements K and O on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of K: _______                              Mass (g) of K: ________
Mass (g) of O: _______                              Mass (g) of O: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 
 
 

 
Question 9
Atomic Scale Analysis:
Consider the reaction  4 Na    +    O₂    →    2 Na₂O .  Count the number of atoms of the elements Na and O on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Na: _______                             # atoms of Na: ________
# atoms of O: _______                               # atoms of O: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  4 Na    +    O₂    →    2 Na₂O , the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Na and O on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Na: _______                            Mass (g) of Na: ________
Mass (g) of O: _______                              Mass (g) of O: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 
 
 

 
Master Difficulty Level
Question Group 4
Question 10
 
Atomic Scale Analysis:
Consider the reaction  Li₂O   +   H₂O   →   2 LiOH.  Count the number of atoms of the elements Li, O, and H on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Li: ________                             # atoms of Li: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of H: _______                                # atoms of H: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction Li₂O   +   H₂O   →   2 LiOH, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Li, O, and H on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Li: ________                            Mass (g) of Li: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of H: _______                              Mass (g) of H: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question 11
Atomic Scale Analysis:
Consider the reaction  Na₂O   +   H₂O   →   2 NaOH.  Count the number of atoms of the elements Na, O, and H on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Na: ________                           # atoms of Na: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of H: _______                                # atoms of H: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction Na₂O   +   H₂O   →   2 NaOH, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Na, O, and H on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Na: ________                          Mass (g) of Na: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of H: _______                              Mass (g) of H: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question 12
Atomic Scale Analysis:
Consider the reaction  K₂O   +   H₂O   →   2 KOH.  Count the number of atoms of the elements K, O, and H on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of K: ________                              # atoms of K: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of H: _______                                # atoms of H: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction K₂O   +   H₂O   →   2 KOH, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements K, O, and H on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of K: ________                            Mass (g) of K: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of H: _______                              Mass (g) of H: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question Group 5
Question 13
Atomic Scale Analysis:
Consider the reaction  CH₄   +   2 O₂   →   CO₂   +   2 H₂O.  Count the number of atoms of the elements C, H, and O on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of C: ________                             # atoms of C: ________
# atoms of H: _______                                # atoms of H: ________
# atoms of O: _______                               # atoms of O: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction CH₄   +   2 O₂   →   CO₂   +   2 H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements C, H, and O on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of C: ________                            Mass (g) of C: ________
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of O: _______                              Mass (g) of O: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question 14
Atomic Scale Analysis:
Consider the reaction  2 C₂H₆   +   7 O₂   →   4 CO₂   +   6 H₂O.  Count the number of atoms of the elements C, H, and O on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of C: ________                             # atoms of C: ________
# atoms of H: _______                                # atoms of H: ________
# atoms of O: _______                               # atoms of O: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  2 C₂H₆   +   7 O₂   →   4 CO₂   +   6 H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements C, H, and O on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of C: ________                            Mass (g) of C: ________
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of O: _______                              Mass (g) of O: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question 15
Atomic Scale Analysis:
Consider the reaction  2 CH₃OH   +   3 O₂   →   2 CO₂   +   4 H₂O.  Count the number of atoms of the elements C, H, and O on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of C: ________                             # atoms of C: ________
# atoms of H: _______                                # atoms of H: ________
# atoms of O: _______                               # atoms of O: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  2 CH₃OH   +   3 O₂   →   2 CO₂   +   4 H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements C, H, and O on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of C: ________                            Mass (g) of C: ________
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of O: _______                              Mass (g) of O: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question Group 6
Question 16
Atomic Scale Analysis:
Consider the reaction  2 KClO₃   →   2 KCl   +   3 O₂.  Count the number of atoms of the elements K, Cl, and O on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of K: ________                              # atoms of K: ________
# atoms of Cl: _______                               # atoms of Cl: ________
# atoms of O: _______                               # atoms of O: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  2 KClO₃   →   2 KCl   +   3 O₂, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements K, Cl, and O on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of K: ________                            Mass (g) of K: ________
Mass (g) of Cl: _______                             Mass (g) of Cl: ________
Mass (g) of O: _______                              Mass (g) of O: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question 17
Atomic Scale Analysis:
Consider the reaction  2 Al(OH)₃   →   Al₂O₃   +   3 H₂O.  Count the number of atoms of the elements Al, O, and H on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Al: ________                             # atoms of Al: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of H: _______                                # atoms of H: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  2 Al(OH)₃   →   Al₂O₃   +   3 H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Al, O, and H on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Al: ________                           Mass (g) of Al: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of H: _______                              Mass (g) of H: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question 18
Atomic Scale Analysis:
Consider the reaction  2 Fe(OH)₃   →   Fe₂O₃   +   3 H₂O.  Count the number of atoms of the elements Fe, O, and H on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Fe: ________                            # atoms of Fe: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of H: _______                                # atoms of H: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  2 Fe(OH)₃   →   Fe₂O₃   +   3 H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Fe, O, and H on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Fe: ________                          Mass (g) of Fe: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of H: _______                              Mass (g) of H: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Wizard Difficulty Level
Question Group 7
Question 19
Atomic Scale Analysis:
Consider the reaction  Al(OH)₃   +   3 HCl   →   AlCl₃   +   3 H₂O.  Count the number of atoms of the elements Al, O, H, and Cl on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Al: ________                             # atoms of Al: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of H: _______                                # atoms of H: ________
# atoms of Cl: _______                               # atoms of Cl: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  Al(OH)₃   +   3 HCl   →   AlCl₃   +   3 H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Al, O, H, and Cl on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Al: ________                           Mass (g) of Al: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of Cl: _______                             Mass (g) of Cl: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question 20
Atomic Scale Analysis:
Consider the reaction  Fe(OH)₃   +   3 HCl   →   FeCl₃   +   3 H₂O.  Count the number of atoms of the elements Fe, O, H, and Cl on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Fe: ________                            # atoms of Fe: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of H: _______                                # atoms of H: ________
# atoms of Cl: _______                               # atoms of Cl: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  Fe(OH)₃   +   3 HCl   →   FeCl₃   +   3 H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Fe, O, H, and Cl on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Fe: ________                          Mass (g) of Fe: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of Cl: _______                             Mass (g) of Cl: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question 21
Atomic Scale Analysis:
Consider the reaction  Cr(OH)₃   +   3 HCl   →   CrCl₃   +   3 H₂O.  Count the number of atoms of the elements Cr, O, H, and Cl on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Cr: ________                            # atoms of Cr: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of H: _______                                # atoms of H: ________
# atoms of Cl: _______                               # atoms of Cl: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  Cr(OH)₃   +   3 HCl   →   CrCl₃   +   3 H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Cr, O, H, and Cl on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Cr: ________                           Mass (g) of Cr: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of Cl: _______                             Mass (g) of Cl: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question Group 8
Question 22
Atomic Scale Analysis:
Consider the reaction  Mg(OH)₂   +   CO₂   →   MgCO₃   +   H₂O.  Count the number of atoms of the elements Mg, O, H, and C on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Mg: ________                           # atoms of Mg: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of H: _______                                # atoms of H: ________
# atoms of C: _______                                # atoms of C: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  Mg(OH)₂   +   CO₂   →   MgCO₃   +   H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Mg, O, H, and C on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Mg: ________                         Mass (g) of Mg: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of C: _______                              Mass (g) of C: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question 23
Atomic Scale Analysis:
Consider the reaction  Ca(OH)₂   +   CO₂   →   CaCO₃   +   H₂O.  Count the number of atoms of the elements Ca, O, H, and C on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Ca: ________                           # atoms of Ca: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of H: _______                                # atoms of H: ________
# atoms of C: _______                                # atoms of C: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  Ca(OH)₂   +   CO₂   →   CaCO₃   +   H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Ca, O, H, and C on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Ca: ________                          Mass (g) of Ca: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of C: _______                              Mass (g) of C: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question 24
Atomic Scale Analysis:
Consider the reaction  Ba(OH)₂   +   CO₂   →   BaCO₃   +   H₂O.  Count the number of atoms of the elements Ba, O, H, and C on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of Ba: ________                           # atoms of Ba: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of H: _______                                # atoms of H: ________
# atoms of C: _______                                # atoms of C: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  Ba(OH)₂   +   CO₂   →   BaCO₃   +   H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements Ba, O, H, and C on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of Ba: ________                          Mass (g) of Ba: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of C: _______                              Mass (g) of C: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question Group 9
Question 25
Atomic Scale Analysis:
Consider the reaction  2 HCl   +   Mg(OH)₂   →   MgCl₂   +   2 H₂O.  Count the number of atoms of the elements H, Cl, Mg, and O on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of H: _______                                # atoms of H: ________
# atoms of Cl: _______                               # atoms of Cl: ________
# atoms of Mg: ________                           # atoms of Mg: ________
# atoms of O: _______                               # atoms of O: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
Macroscopic Scale Analysis:
For the reaction  2 HCl   +   Mg(OH)₂   →   MgCl₂   +   2 H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements H, Cl, Mg, and O on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of Cl: _______                             Mass (g) of Cl: ________
Mass (g) of Mg: ________                         Mass (g) of Mg: ________
Mass (g) of O: _______                              Mass (g) of O: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 
 

 
Question 26
Atomic Scale Analysis:
Consider the reaction  H₂SO₄   +   2 NaOH   →   Na₂SO₄   +   2 H₂O.  Count the number of atoms of the elements H, S, O, and Na on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of H: _______                                # atoms of H: ________
# atoms of S: _______                                # atoms of S: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of Na: ________                           # atoms of Na: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
 
Macroscopic Scale Analysis:
For the reaction  H₂SO₄   +   2 NaOH   →   Na₂SO₄   +   2 H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements H, S, O, and Na on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of S: _______                              Mass (g) of S: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of Na: ________                          Mass (g) of Na: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.
 

 
Question 27
Atomic Scale Analysis:
Consider the reaction  H₃PO₄   +   3 NaOH   →   Na₃PO₄   +   3 H₂O.  Count the number of atoms of the elements H, P, O, and Na on both sides of the equation.
Reactant Side:                                            Product Side:
# atoms of H: _______                                # atoms of H: ________
# atoms of P: _______                                # atoms of P: ________
# atoms of O: _______                               # atoms of O: ________
# atoms of Na: ________                           # atoms of Na: ________
 
Which statement is an accurate summary of this analysis?
a. Atoms of one element are changed into atoms of another element but the total number of atoms does not change.
b. Atoms of one element are changed into atoms of another element; the total number of atoms changes during the reaction.
c. The number of atoms of each of the elements is conserved (does not change) during this reaction.
 
 
Macroscopic Scale Analysis:
For the reaction  H₃PO₄   +   3 NaOH   →   Na₃PO₄   +   3 H₂O, the coefficients indicate the number of moles of each reactant and product involved in the reaction. Calculate the grams of the elements H, P, O, and Na on both sides of the equation.
 
Reactant Side:                                            Product Side:
Mass (g) of H: _______                              Mass (g) of H: ________
Mass (g) of P: _______                              Mass (g) of P: ________
Mass (g) of O: _______                              Mass (g) of O: ________
Mass (g) of Na: ________                          Mass (g) of Na: ________
 
Which statement is an accurate summary of this analysis?
a. The mass of one or more of the elements changes; but the total mass remains constant.
b. The mass of one or more of the elements changes; the total mass also changes.
c. The mass of each element is conserved (does not change) during this reaction.