Stoichiometry
section
t2.t What is stoichiometry?
ln your textbook, read about stoichiometryand the balancedequation.
For each statement below, wite true or false.
1. The studyof the quantitativerelationships
betweenthe amountsof
reactantsusedand the amountsof productsformed by a chemicalreaction
is calledstoichiometrv.
2 . Stoichiometryis basedon the law of conservationof mass.
3 . ln any chemicalreaction,the massof the productsis less than the massof
the reactants.
4. The coefficientsin a chemicalequationrepresentnot only the number of
individual particlesbut also the number of moles of particles.
5 . The massof eachreactantand product is relatedto its coefficientin the
balancedchemicalequationfor the reactionby its molar mass.
Complete the table below, using information representedin the chemical equation for
the combustion of methanol. an alcohol.
methanol* oxygen --+ carbondioxide + water
2CHjOH(l) + 3O2 G) -+ 2CO2G) + 4HrO(g)
A
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5ubstance
tolar illass (g/nol)
6. Methanol
32.05
7. Oxygengas
32.00
8 . C a r b o nd i o x i d e
44.O1
9. water
18.02
Number of
ilolecules
l{umber of
iloles (mol)
Mass (g)
3
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10. Whal are the reactants?
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1 1 . W h a tare the products?
12. What is the total massof the reactants?
13. What is the total massof the products?
14. How do the total massesof the reactantsand productscompare?
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C h e m i s t r yM
: a t t e r a n d C h a n g e. C h a p t e r 1 2
67
Section 12.1 continued
ln your textbook, read about mole ratios.
Answer the questions about the following chemical reaction.
sodium + iron(III) oxide --+ sodium oxide * iron
6Na(s) + FerOr(s) --; 3NarO(s) + 2Fe(s)
15. What is a mole ratio?
16. How is a mole ratio written?
1 7 . Predict the number of mole ratios for this reaction.
1 8 . What are the mole ratios for this reaction?
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19. What is the mole ratio relating sodium to iron?
,
What is the mole ratio relating iron to sodium?
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21. Which mole ratio has the largestvalue?
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Chemistry:Matter and Change. Chapter 12
Study Guide for Content Mastery