Chem 2202
Mid Term Practice
1
Chem 2202 – Additional Mid-Term Samples
1.
Which of the following compounds would form a precipitate in a chemical reaction?
A) AgCl
B) Na2S
C) CuSO4
D) NH4NO3
2.
How many moles of ammonia gas would be present in a volume of 38.2 L at STP?
A) 0.586 mol
B) 1.71 mol C) 22.4 mol D) 38.2 mol
3.
What would be the concentration of 100.0 mL of a copper (II) sulfate solution made by
diluting 10.0 mL of a 1.00 mol/L copper (II) sulfate solution?
A) 0.100 mol/L
B) 1.00 mol/L
C) 10.0 mol/L
D) 100.0 mol/L
4.
Which of the following solutions would have the greatest concentration?
A)
0.125 mol of NaCl dissolved in 50.0 mL of water
B)
1.25 mol of CuSO4 dissolved in 100.0 mL of water
C)
2.55 mol of NH4NO3 dissolved in 500.0 mL of water
D)
10.5 mol of NaHCO3 dissolved in 2.00 L of water
5.
What is the percent yield if 2.45 g of precipitate is produced in a reaction with a
theoretical yield of 2.82 g?
A) 2.45%
B) 13.1%
C) 86.9%
D) 115.1%
6.
What is the limiting reagent when 2.5 mol of hydrogen gas reacts with 1.5 mol of oxygen
gas to form water?
A)
Hydrogen
B) oxygen
C) water
D) not enough information given
7.
Which of the following terms refers to a solution in which no additional solute can be
dissolved?
A)
Concentrated
B) dilute
C) saturated
D) soluble
8.
Which of the following dissociation equations is written incorrectly?
A)
CuSO4 (s) → Cu2+ (aq) + SO42- (aq)
B)
NaCl (s) → Na+ (aq) + Cl- (aq)
C)
(NH4)2SO4 (s) → NH4+ (aq) + SO42- (aq)
D)
CaCO3 (s) → Ca2+ (aq) + CO32- (aq)
9.
An unknown substance is analyzed and found to have a percent composition of 47%
carbon, 7% hydrogen, and 46% chlorine by mass. What is its empirical formula?
A)
C3H5Cl
B) CHCl
C) C2HCl2
D) CH2Cl2
10.
How many moles of nitrogen gas would be produced when 1.24 mol of sodium nitride
decomposes in the following reaction: 2 NaN3 (s) → 2 Na (s) + 3 N2 (g)?
A)
1.24 mol
B) 1.86 mol C) 2.00 mol D) 3.00 mol
Chem 2202
Mid Term Practice
2
11.
How many moles of sodium ions are produced when 1.25 mol of Na2CO3 dissociates in
water?
A) 1.00 mo B) 1.25 mol C) 2.00 mol D) 2.50 mol
12.
Avogadro's constant (NA) is valued as...
A) 144
B) 12.01 g/mol
C) 6.02 x 1023 mol-1 D) 1.204 x 10-3
13.
In 1.00 mol of nitrogen gas, there are...
A) 14.01 nitrogen atoms
B) 6.02 x 1023 nitrogen atoms
C) 28.02 nitrogen molecules
D) 1.20 x 1024 nitrogen atoms
14.
STP is best defined as...
A)
0oC and 100 kPa atmospheric pressure
B)
25oC and 100 kPa atmospheric pressure
C)
25oC and 101 kPa atmospheric pressure
D)
0oC and 101.3 kPa atmospheric pressure
15.
Which is a substance, which dissolves in another substance?
A) Solute
B) Solution
C) Solvent
D) Suspension
16.
Which substance, when dissolved in water is a non-electrolyte?
A) CH3OH
B) HNO3
C) Cu(NO3)2
D) NaCl
17.
The art of glass etching was boosted with the discovery that hydrofluoric acid,
HF(aq), reacts with glass. Calculate the volume of 0.284M HF acid that contains
0.352mol of solute.
A) 0.100L
B) 1.24L
C) 0.807L
D) 24.8L
18.
What is the concentration of a solution containing 4.0g of NaOH(s) dissolved in
water to make 500mL of solution?
A) 0.10M
B) 0.50M
C) 0.20M
D) 1.0M
19.
What happens when a solution of AgNO3(aq) is diluted?
A. The concentration of the solution decreases.
B. The mass of the solute decreases.
C. The number of moles of solute decreases.
D. The volume of the solvent decreases.
20.
In the lab 6.55g of silver chloride precipitate was collected, but the equation predicted
that 7.85g should be produced. What is the percent yield for the reaction?
A. 0.834%
B) 83.44%
C) 1.20%
D) 119.85%
21.
The products in the reaction between iron and silver nitrate are
A. Fe(NO3)2(aq) and Ag(s)
B) Fe(NO3)3(aq) and Ag(s)
B. Fe(NO3)3(aq) and AgNO3(aq)
D) AgNO3(aq) and Fe(s)
enough
Chem 2202
Mid Term Practice
3
22.
Calculate the concentration of a sodium nitrate solution with a volume of 300.0 mL and
containing 25.0 g of sodium nitrate. (5%)
23.
Propane, C3H8 (g), burns in oxygen, O2 (g), to produce CO2 (g) and H2O (g). What mass of
propane is needed to burn 25.0 mol of oxygen? (5%)
24.
(a)
Hydrogen gas is produced when sodium metal is added to water. Calculate the
mass of sodium needed to produce 20.0 L of hydrogen at STP given the equation: 2 Na (s)
+ 2 H2O (l) → H2 (g) + 2 NaOH (aq). (5%)
(b)
25.
Calculate the percent yield for an experiment which produced 5.62 g of PbCl2
when the theoretical yield was calculated to be 6.14 g. (5%)
(a)
Determine the limiting and excess reagent when 69.0 g of iron (III) oxide reacts
with 28.3 g of carbon monoxide in the following reaction: (5%)
Fe2O3 (s) + 3 CO (g) → 2 Fe (s) + 3 CO2 (g)
(b)
Calculate the mass of Fe produced in (a). (5%)
26.
Write a balanced dissociation equation for the dissociation of Li3PO4. Be sure to include
the appropriate charges. (2%)
27.
A chemical company needs to ship 20.0L of 6.0M sulfuric acid for making car batteries.
What volume of concentrated (17.6M) sulfuric acid is needed to make the car battery
acid? (5%)
28.
How many grams of sulfur dioxide are in 36.2L at STP? (3%)
29.
Write the dissociation equation 0.25M Ammonium sulfide. What is the
of each ion? (5%)
30.
Ammonium Sulfate is used as a source of nitrogen in some fertilizers. It reacts
with
sodium hydroxide to produce sodium sulfate, water and ammonia. What mass of
sodium hydroxide is required to react completely with 15.4g of
(NH4)2SO4? (5%)
concentration