Practice Problems 8
Chapter 3
CHE 151
Graham/07
1.
In the reaction
P4 + 5 O2  2 P2O5
How many moles of oxygen are consumed each time 0.500 mole of P2O5 is formed?
2.
How many moles of oxygen are consumed in burning 125 g of benzene, C6H6?
3.
The equation for the neutralization of Citric acid is as follows:
H3C6H5O7 + 3NaOH  Na3C6H5O7 + 3H2O
How many grams of sodium hydroxide are required to react with 10.50 g
of Citric acid?
4.
In reacting aluminum carbonate with hydrochloric acid according to the equation
below 57.6 mg of carbon dioxide was formed.
Al2(CO3)3 + 6 HCl  2 AlCl3 + 3 H2O + 3 CO2
a.) What mass of aluminum carbonate was reacted?
b.) If this reaction has a 63.1% yield what mass of water will be produced?
5.
a.) What is the theoretical yield of oxygen from the decomposition of 5.00 g
of potassium chlorate?
2 KClO3  3 O2 + 2 KCl
b.) If the amount of oxygen actually obtained from the decomposition
is 1.50 g. Calculate the percent yield for this reaction.
6.
7.
Chlorine and fluorine react to form gaseous chlorine trifluoride, ClF3.
You start with 3.40 moles of Cl2 and 7.16 moles of F2.
a.)
Write a balanced equation for the reaction.
b.)
What is the limiting reactant?
c.)
What is the theoretical yield (in grams) of ClF3 ?
d.)
How many moles of the excess reactant remain unreacted?
How many g of AgNO3 will be produced from 12.0 g of Ag
Molar masses
Ag = 107.9 g/mole
HNO3 = 63.02 g/mole
AgNO3 = 169.9 g/mole
and 12.5 g of HNO3 ?
Ag(s) + 2 HNO3(aq)  AgNO3(aq) + NO2(g) + H2O(l)
8.
a.) 56.2 g of Cu are combined with 30.0 g of HNO3 (molar mass = 63.02g/mole),
according to the reaction below. Which reactant is limiting and what is the
theoretical yield of Cu(NO3)2 ? (molar mass = 187.6g/mole)
3Cu + 8HNO3  3Cu(NO3)2 + 2NO + 4H2
b.) If 27.9 g of Cu(NO3)2 is obtained from the reaction above, calculate the percent
yield.
c.) How many grams of the excess reactant remain?
9.
50.70 g of CuCl2 solid is dissolved in water to produce exactly 500.0 mL of
solution. Calculate the molarity of the CuCl2 solution.
10.
What is the molarity of a KI solution that has 13.39 g KI in 450.0 mL of
solution?
11.
How many grams of NaCl (molar mass 58.44 g/mole) are present in 325.0 mL
of a 0.5055 M NaCl solution?
12.
How many liters of 3.50 M NaC2H3O2 (molar mass 82.03 g/mole) can be
prepared from 7.50 g of the salt?
13.
Describe how you would prepare 1 liter of 0.15 M KI solution.
14.
To what total volume must 55.4 mL of 6.00 M HCl acid be diluted to produce
a 1.75 M HCl acid solution?
15.
How much solvent must be added to 250.0 mL of a 1.500 M NaCl solution to
decrease its concentration to 0.9500 M ?
KI (molar mass=
166.0 g/mole)
16.
As a Lab Tech, you are asked to prepare 250.0 mL of 0.25 M KOH. You are
all out of KOH solid, but you do find a solution of 6.0 M KOH on the shelf.
Show with a calculation how you would use the available solution to fill the
request.
17.
What volume (in liters) of a 4.50 M HCl solution is needed to react
completely with 0.500 L of a 6.00 M Na3PO4 solution according to the
following reaction ?
Na3PO4(aq) + 3 HCl(aq)  3 NaCl(aq) + H3PO4(aq)
18.
How many grams of Cr(OH)3 can be produced from the reaction of 1.50 L of
0.275 M Cr(NO3)3 with excess 1.00 M NaOH ? (molar Mass Cr(OH)3 = 103.0 g/mole)
Cr(NO3)3(aq) + 3 NaOH(aq)  Cr(OH)3(s) + 3 NaNO3(aq)
19.
Molar mass
NaHCO3
84.01 g/mole
Some sulfuric acid is spilled on the lab bench. It can be neutralized
bysprinkling sodium bicarbonate on it and then mopping up the resultant
solution. The reaction is as follows:
2 NaHCO3 + H2SO4 
Na2SO4 + 2CO2 + 2H2O
Sodium bicarbonate is added until the fizzing due to the formation of CO2(g)
stops. If 35 mL of 6.0 M H2SO4 was spilled, what is the minimum mass of
NaHCO3 that must be added to the spill to neutralize the acid?