AnswersNY-Chemistry Term 1 HillcrestUnit Test

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Consider the chemical equation.2H2 + O2 2H2OWhat is the percent yield of H2O if 87.0 g of H2O is produced by combining 95.0 g of O2 and 11.0 g of H2?Use .

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A
56.5%
B
59.0%
C
88.5%
D
99.7%
2
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The gas in the piston is at constant temperature. A student increases the pressure on the piston from 2 atm to 3 atm.Which gas law would a student use to investigate this situation?

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A
Boyle’s law
B
Charles’s law
C
Gay-Lussac’s law
D
ideal gas law
3

Consider the chemical equation. 2NBr3 + 3NaOH N2 + 3NaBr + 3HOBrIf there are 40 mol of NBr3 and 48 mol of NaOH, what is the excess reactant?

Question illustration
A
N2
B
NBr3
C
NaOH
D
HOBr
4

Which describes the volume of 1 mol of gas at standard temperature and pressure?

A
The volume is greater for a larger mass of gas.
B
The volume is the same for any gas.
C
The volume depends on the size of the container.
D
The volume varies with the pressure.
5

A sample of sodium hydroxide (NaOH) has a mass of 160.0 g. The molar mass of NaOH is 40.00 g/mol. How many moles of NaOH does this sample contain?

A
4.000 moles
B
40.00 moles
C
160.0 moles
D
6,400 moles
6

The incomplete table below shows a comparison of the different gas laws.NameVariablesConstantsEquationBoyle's law pressure, volume? Charles’s lawvolume, temperature??temperature, pressurevolume, moles of gas?pressure, temperature, volume?What is assumed to be constant when using the combined gas law?

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A
pressure
B
number of moles
C
volume and moles of gas
D
pressure and temperature
7

Which must be the same when comparing 1 mol of oxygen gas, O2, with 1 mol of carbon monoxide gas, CO?

A
the mass
B
the volume
C
the number of molecules
D
the number of oxygen atoms
8

Copper metal (Cu) reacts with silver nitrate (AgNO3) in aqueous solution to form Ag and Cu(NO3)2. The balanced chemical equation is shown below.Cu + 2AgNO3 Cu(NO3)2 + 2AgThe molar mass of Cu is 63.5 g/mol. The molar mass of Ag is 107.9 g/mol. What mass, in grams, of Ag is produced from a reaction of 31.75 g of Cu?

Question illustration
A
26.95 grams
B
107.9 grams
C
215.91 grams
D
431.82 grams
9

Consider the balanced equation below. 2H2S + 3O2 2SO2 + 2H2OWhich option gives the correct mole ratios?

Question illustration
A
H2S:SO2 = 2:2 and O2:H2O = 3:2
B
H2S:SO2 = 2:3 and O2:H2O = 3:2
C
H2S:SO2 = 4:4 and O2:H2O = 5:4
D
H2S:SO2 = 4:6 and O2:H2O = 4:4
10

The following balanced equation shows the formation of ammonia.N2 + 3H2 2NH3How many moles of nitrogen are needed to completely convert 6.34 mol of hydrogen?

Question illustration
A
1.02 mol
B
2.11 mol
C
12.68 mol
D
19.02 mol
11

If a gas is moved from a large container to a small container but its temperature and number of moles remain the same, what would happen to the pressure of the gas?

A
It would increase.
B
It would be halved.
C
It would stay the same.
D
It would slightly decrease.
12

Avogadro’s number was calculated by determining the number of atoms in

A
12.00 g of carbon-12.
B
14.00 g of carbon-12.
C
12.00 g of oxygen.
D
14.00 g of oxygen.
13

What is the molar mass of fluorine, F2?

A
9.00 g/mol
B
18.00 g/mol
C
19.00 g/mol
D
38.00 g/mol
14

A sample of calcium oxide (CaO) has a mass of 2.80 g. The molar mass of CaO is 56.08 g/mol. How many moles of CaO does this sample contain?

A
0.0499 moles
B
20.0 moles
C
58.9 moles
D
157 moles
15

The volume of a gas is 0.450 L when its pressure is 1.00 atm. If the temperature of the gas does not change, what is the pressure when its volume is changed to 2.00 L?Use .

Question illustration
A
0.225 atm
B
0.444 atm
C
2.25 atm
D
4.44 atm
16

Which statement correctly describes the actual yield and the theoretical yield of a reaction?

A
The actual yield is calculated from the reactant amounts, but the theoretical yield must be measured for each instance of a reaction.
B
The actual yield is calculated from the amount of the limiting reactant, and the theoretical yield is calculated from the amount of the excess reactant.
C
The actual yield depends on the reaction conditions, but the theoretical yield varies only with reactant amounts.
D
The actual yield represents the maximum yield possible, and the theoretical yield assumes perfect reaction conditions.
17

Which statement best describes a mole?

A
It is used mainly for writing chemical formulas.
B
It is used for chemical equations that have reversible reactions.
C
It is used for directly comparing the amounts of substances.
D
It is used mainly for dealing with fluid substances.
18

Which statement can best be concluded from the ideal gas law?

A
The product of pressure and volume of an ideal gas is proportional to the absolute temperature.
B
All collisions between atoms or molecules are perfectly elastic and are not the result of any attractive forces.
C
The temperature, pressure, and volume of a gas are all related.
D
The behavior of a gas under real conditions does not obey the ideal gas law.
19

The chemical equation below shows the combustion of propane (C3H8).C3H8 + 5O2 3CO2 + 4H2OThe molar mass of oxygen gas (O2) is 32.00 g/mol. The molar mass of C3H8 is 44.1 g/mol. What mass of O2, in grams, is required to completely react with 0.025 g C3H8?

Question illustration
A
0.018 grams
B
0.034 grams
C
0.045 grams
D
0.091 grams
20

Which best defines partial pressure in a mixture of gases?

A
pressure that is exerted by all the gases of a mixture on the container
B
pressure that is exerted by one gas as if it occupied a container by itself
C
half of the pressure that is exerted by the gases of a mixture on the container
D
sum of the individual pressures that are exerted by two or more gases

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