AnswersEO Chemistry 7320BUnit Test

Unit Test — Unit test Answers

25 verified answers2 views
1
Free Preview

Consider the following intermediate chemical equations.How will oxygen appear in the final chemical equation?

Question illustration
A
as a product
Option A
B
as a reactant
Option B
C
O(g) as a product
D
2O(g) as a reactant
2
Free Preview

Which reaction is endothermic?

A
HCl + NaOH NaCl + H2O + 58 kJ
Option A
B
6CO2 + 12H2O + energy C6H12O6 + 6O2 + 6H2O
Option B
C
2Na + Cl2 2NaCl + energy
Option C
D
2C2H6 + 7O2 4CO2 + 6H2O + 2,502 kJ
Option D
3

A sample of iron (Fe) with a mass of 200.0 g releases 9,840 cal when it freezes at its freezing point. What is the molar heat of fusion for iron?Use .

Question illustration
A
2,747.7 cal/mol
B
2,771.8 cal/mol
C
2,811.7 cal/mol
D
3,280.0 cal/mol
4

Consider the following intermediate chemical equations.When you form the final chemical equation, what should you do with CO?

Question illustration
A
Cancel out CO because it appears as a reactant in one intermediate reaction and a product in the other intermediate reaction.
B
Add the two CO molecules together, and write them as reactants in the final chemical reaction.
C
Write CO only once as a reactant in the final chemical reaction.
D
Write CO as a reactant and a product in the final chemical reaction.
5

How is the kinetic energy of the particles of a substance affected during a phase change?

A
Kinetic energy increases during exothermic changes and decreases during endothermic changes.
B
Kinetic energy decreases during exothermic changes and increases during endothermic changes.
C
Kinetic energy does not change, but the potential energy does.
D
Kinetic energy changes in the opposite way that the potential energy changes.
6

What explains the key difference between a bomb calorimeter and a coffee cup calorimeter?

A
A bomb calorimeter is 10 times larger but works the same way.
B
A bomb calorimeter measures heat for liquid products only.
C
A bomb calorimeter has a separate chamber to hold substances and can even measure heat gain or loss for reactions that do not occur in water.
D
A bomb calorimeter can measure heat gain or loss in gaseous reactions but is not useful for reactions that occur at high pressures and temperatures.
7

Complete combustion of a 0.350 g sample of a compound in a bomb calorimeter releases 14.0 kJ of heat. The bomb calorimeter has a mass of 1.20 kg and a specific heat of 3.55 J/(gi°C). If the initial temperature of the calorimeter is 22.5°C, what is its final temperature?Use .

Question illustration
A
19.2°C
B
25.8°C
C
34.2°C
D
72.3°C
8

Which best describes heat?

A
energy that is carried by electric and magnetic fields
B
energy that decreases as a car slows to a stop
C
energy that increases as a book is lifted to a higher shelf
D
energy that flows from a hot mug of tea to a cold hand
9

How should the baking of a pizza be categorized?

A
as an exothermic process because the dough releases heat
B
as an endothermic process because the dough releases heat
C
as an exothermic process because the dough absorbs heat
D
as an endothermic process because the dough absorbs heat
10

A welding torch produces a flame by burning acetylene fuel in the presence of oxygen. This flame is used to melt a metal. Which energy transformation represents this process?

A
chemical energy into thermal energy
B
kinetic energy into potential energy
C
kinetic energy into electromagnetic energy
D
potential energy into chemical energy
11

Ammonia, NH3 (Hf = –45.9 kJ), reacts with oxygen to produce water (Hf = –241.8 kJ) and nitric oxide, NO (Hf = 91.3 kJ), in the following reaction:What is the enthalpy change for this reaction? Use .

Question illustration
A
–902 kJ
B
–104.6 kJ
C
104.6 kJ
D
900.8 kJ
12

Which describes the enthalpy change associated with an endothermic reaction?

A
It is negative because the enthalpy of the products is greater than the enthalpy of the reactants.
B
It is positive because the enthalpy of the products is greater than the enthalpy of the reactants.
C
It is negative because the enthalpy of the reactants is greater than the enthalpy of the products.
D
It is positive because the enthalpy of the reactants is greater than the enthalpy of the products.
13

A metal sample is heated and placed into the water in a calorimeter at room temperature. Which statement best describes how the calorimeter can be used to determine the specific heat capacity of the metal sample?

A
Energy transfers to the metal from the water and calorimeter until they are all at room temperature.
B
Energy transfers from the metal to the water and calorimeter until they are all at room temperature.
C
Energy transfers to the metal from the water and calorimeter until they all reach a single temperature.
D
Energy transfers from the metal to the water and calorimeter until they all reach a single temperature.
14

Which statement defines calorimetry?

A
the conservation of energy
B
a unit of energy that is used when calculating energy exchange
C
a device that is used to measure the heat that is gained or lost during a chemical change
D
the measurement of energy that is given off or absorbed in a physical or chemical process
15

Nitrogen dioxide, NO2(g) (Hf = 33.84 kJ/mol), is decomposed according to the following reaction:What is the enthalpy change when 2.50 mol of nitrogen dioxide decomposes? Use .

Question illustration
A
13.5 kJ of energy released
B
13.5 kJ of energy absorbed
C
84.6 kJ of energy released
D
84.6 kJ of energy absorbed
16

Which statement best describes the direction of heat flow by conduction between two samples of the same material?

A
Heat flows from faster molecules to slower molecules when they are near.
B
Heat flows from faster molecules to slower molecules when they collide.
C
Heat flows from slower molecules to faster molecules when they are near.
D
Heat flows from slower molecules to faster molecules when they collide.
17

Consider the following enthalpy diagram:Which label shows the overall enthalpy change and is the reaction exothermic or endothermic?

Question illustration
A
A, exothermic.
B
B, exothermic.
C
C, endothermic.
D
D, endothermic.
18

Two metal blocks that have slightly different temperatures are placed next to one another. After five minutes, they both have lower but equal temperatures. According to the law of conservation of energy, what most likely happened?

A
Energy was created inside the blocks.
B
Energy was destroyed inside the blocks.
C
Energy was absorbed into the blocks from outside the system.
D
Energy was transferred from the warmer block to the cooler block.
19

Which is the best example of how electromagnetic energy is used?

A
a pot of boiling water on a gas stove
B
a patient receiving an X-ray in a hospital
C
a car burning gasoline to power the engine
D
a car of a roller coaster moving quickly down a slope
20

H2O has a Hvap = 40.7 kJ/mol. What is the quantity of heat that is released when 27.9 g of H2O condenses?Use .

Question illustration
A
60.00 kJ
B
61.05 kJ
C
63.09 kJ
D
68.60 kJ

Did you find these answers helpful?

More from this Course

Quiz
25 verified answers

Unit Test

Quiz
25 verified answers

Unit Test

Quiz
10 verified answers

Properties of Water

Unit Test — Unit test Answers — EO Chemistry…