The Foundations of Chemistry

(a) Balance the equation.

(b) How many atoms are in 0.250 moles of calcium car-

bonate?

(c) What number of carbon dioxide molecules is released

on the reaction of 0.250 moles of calcium carbonate?

0 14.How many moles of oxygen can be obtained by the de-

composition of 8.0 mol of reactant in each of the follow-

ing reactions?

(a) 2KClO 3 88n2KCl
3O 2

(b) 2H 2 O 2 88n2H 2 O
O 2

(c) 2HgO88n2Hg
O 2

(d) 2NaNO 3 88n2NaNO 2 
O 2

(e) KClO 4 88nKCl
2O 2

0 15.For the formation of 8.0 mol of water, which reaction uses

the most nitric acid?

(a) 3Cu
8HNO 3 88n3Cu(NO 3 ) 2 
2NO
4H 2 O

(b) Al 2 O 3 
6HNO 3 88n2Al(NO 3 ) 3 
3H 2 O

(c) 4Zn
10HNO 3 88n

4Zn(NO 3 ) 2 
NH 4 NO 3 
3H 2 O

0 16.Consider the reaction

not balanced

NH 3 
O 2 8888888888nNO
H 2 O

For every 25.00 mol of NH 3 , (a) how many moles of O 2

are required, (b) how many moles of NO are produced,

and (c) how many moles of H 2 O are produced?

0 17.What masses of cobalt(II) chloride and of hydrogen fluor-

ide are needed to prepare 15.0 mol of cobalt(II) fluoride

by the following reaction?

CoCl 2 
2HF88nCoF 2 
2HCl

0 18.We allow 24.0 g of methane, CH 4 , to react as completely

as possible with excess oxygen, O 2 , to form CO 2 and wa-

ter. Write the balanced equation for this reaction. What

mass of oxygen reacts?

*19.Calculate the mass of calcium required to react with

3.770 g of carbon during the production of calcium carbide,

CaC 2.

0 20.Sodium iodide, NaI, is a source of iodine used to produce

iodized salt.

(a) Write the balanced chemical equation for the reaction

of sodium and iodine.

(b) How many grams of sodium iodide are produced by

the reaction of 93.25 grams of iodine?

0 21.Consider the reaction

2NO
Br 2 88n2NOBr

For every 7.50 mol of bromine that reacts, how many

moles of (a) NO react and (b) NOBr are produced?

0 22.A sample of magnetic iron oxide, Fe 3 O 4 , reacts completely

with hydrogen at red heat. The water vapor formed by the

reaction

heat

Fe 3 O 4 
4H 2 8888n3Fe
4H 2 O

is condensed and found to weigh 18.75 g. Calculate the

mass of Fe 3 O 4 that reacted.

0 23.Iron(III) oxide, Fe 2 O 3 , is a result of the reaction of iron

with the oxygen in air.

(a) What is the balanced equation for this reaction?

(b) What number of moles of iron react with 15.25 mol

of oxygen from the air?

(c) What mass of iron is required to react with 15.25 mol

of oxygen?

0 24.Calculate the number of molecules of propane, C 3 H 8 , that

will produce 4.80 grams of water when burned in excess

oxygen, O 2.

0 25.What mass of pentane, C 5 H 12 , produces 4.52 1022 CO 2

molecules when burned in excess oxygen, O 2?

Limiting Reactant

0 26.How many grams of NH 3 can be prepared from 59.85 g

of N 2 and 12.11 g of H 2?

N 2 
3H 2 88n2NH 3

*27.Silver nitrate solution reacts with calcium chloride solu-

tion according to the equation

2AgNO 3 
CaCl 2 88nCa(NO 3 ) 2 
2AgCl

All of the substances involved in this reaction are soluble

in water except silver chloride, AgCl, which forms a solid

(precipitate) at the bottom of the flask. Suppose we mix

together a solution containing 12.6 g of AgNO 3 and one

containing 8.40 g of CaCl 2. What mass of AgCl is formed?

*28.“Superphosphate,” a water-soluble fertilizer, is sometimes

marketed as “triple phosphate.” It is a mixture of

Ca(H 2 PO 4 ) 2 and CaSO 4 on a 1:2 molebasis. It is formed

by the reaction

Ca 3 (PO 4 ) 2 
2H 2 SO 4 88nCa(H 2 PO 4 ) 2 
2CaSO 4

We treat 300 g of Ca 3 (PO 4 ) 2 with 200 g of H 2 SO 4. How

many grams of superphosphate could be formed?

114 CHAPTER 3: Chemical Equations and Reaction Stoichiometry

0 29.Gasoline is produced from crude oil, a nonrenewable re-

source. Ethanol is mixed with gasoline to produce a fuel

called gasohol. Calculate the mass of water produced when