Deck 10: Energy

Question 1

Perform the indicated conversion: 38.86 kJ =____ kcal

A)
B) 9.288 kcal
C)
D)
E) 0.1077 kcal

Answer 1

9.288 kcal

Question 2

Which of the following is a valid unit for specific heat (or specific heat capacity)?

A) cal/g·°C
B) cal
C) cal/g
D) °C
E) g·°C/cal

Answer 2

cal/g·°C

Question 3

The amount of energy needed to heat 2.00 g mercury from 50.0°C to 85.0°C is 9.87 J. The specific heat capacity of this sample of mercury is

A) 0.141 J/g·°C
B) 0.058 J/g·°C
C) 0.282 J/g·°C
D) 345 J/g·°C
E) 691 J/g·°C

Answer 3

0.141 J/g·°C

Question 4

The specific heat capacity of aluminum is 0.89 J/g·°C. Calculate the amount of energy needed to warm g of aluminum from 73.0°C to 155.0°C.

A)
B)
C)
D)
E) none of these

Question 5

Heat is typically measured in

A) °C
B) °F
C) joules
D) grams

Question 6

A gas absorbs 75 kJ of heat and does 21 kJ of work. Calculate .

A) 54 kJ
B) 96 kJ
C) 3.6 kJ
D) -54 kJ
E) -96 kJ

Question 7

The specific heat capacity of iron is 0.45 J/g·°C. How many joules of energy are needed to warm 1.31 g of iron from 20.00°C to 29.00°C?

A) 17 J
B) 12 J
C) 26 J
D) 11 J
E) 5.3 J

Question 8

Calculate the heat given off when 159.7 g of copper cools from 155.0°C to 23.0°C. The specific heat capacity of copper is 0.385 J/g·°C.

A)
B)
C)
D)
E) none of these

Question 9

Assume that 491.8 J of heat is added to 5.00 g of water originally at 23.0°C. What would be the final temperature of the water? (Specific heat capacity of water = 4.184 J/g·°C.)

A) 23.5 °C
B) 61.5 °C
C) 74.5 °C
D) 46.5 °C
E) none of these

Question 10

Which is larger, one calorie or one joule?

Question 11

A system absorbs 159 kJ of heat, and performs 89 kJ of work on the surroundings. What is of the system?

A) 248 kJ
B) -248 kJ
C) 70 kJ
D) -70 kJ
E) 1.8 kJ

Question 12

How many joules of energy would be required to heat 15.9 g of carbon from 23.6°C to 54.2°C? (Specific heat capacity of carbon = 0.71 J/g·°C.)

A)
B)
C)
D)
E) none of these

Question 13

How much energy will be needed to heat 69.7 gal of water from 22.0°C to 110.0°C? (Note that 1.00 gal weighs 3.77 kg and that water has a specific heat capacity of 4.184 J/g·°C.)

A)
B)
C)
D)
E)

Question 14

The specific heat capacity of silver is 0.24 J/g·°C. How many joules of energy are needed to warm 0.960 g of silver from 25.0°C to 27.5°C?

A) 6.3 J
B) 0.58 J
C) 12.1 J
D) 10.0 J
E) none of these

Question 15

SI units for specific heat capacity are

A) cal
B) cal/g
C) J/g·°C
D) g/mL
E) g·°C/cal

Question 16

The quantity of heat required to change the temperature of 1 g of a substance by 1°C is defined as

A) a joule
B) specific heat capacity
C) a calorie
D) density

Question 17

A 6.75-g sample of gold (specific heat capacity = 0.130 J/g °C) is heated using 55.8 J of energy. If the original temperature of the gold is 25.0°C, what is its final temperature?

A) 88.6 °C
B) 38.6 °C
C) 76.9 °C
D) 73.6 °C
E) 63.6 °C

Question 18

Express in kilocalories.

A)
B)
C) 78.2 kcal
D) 327 kcal
E)

Question 19

Calculate given the following information:

A) 17 kJ
B) 65 kJ
C) -65 kJ
D) -17 kJ
E) 1.7 kJ

Question 20

A 4.60-g sample of iron is heated from 47.0°C to 75.0°C. The amount of energy required is 57.96 J. The specific heat capacity of this sample of iron is

A) 0.450 J/g·°C
B) 1.233 J/g·°C
C) 2.07 J/g·°C
D) 1623 J/g·°C
E) 7465 J/g·°C

Question 21

Energy can be classified as either potential or kinetic energy.

Question 22

The energy gained by the surroundings must be equal to the energy lost by the system.

Question 23

____ is a measure of the random motions of the components of a substance.

A) Heat
B) Temperature
C) Energy
D) Radiation
E) Matter

Question 24

For the reaction Calculate the enthalpy change when 2.80 g of water is produced.

A) 102 kJ
B) 801 kJ
C) -801 kJ
D) 44.4 kJ
E) -44.4 kJ

Question 25

Determine the enthalpy change when 19.4 g of carbon is reacted with oxygen according to the reaction

A) 636 kJ
B)
C) -636 kJ
D) -7.64 kJ
E) 6.76 kJ

Question 26

Perform the indicated conversion: 1.345 kcal =____ J

A)
B) 5.627 J
C)
D)
E) 3.111 J

Question 27

Which of the following processes is endothermic?

A) water droplets condensing on a soda can on a hot summer day
B) an ice pack getting cold (due to ammonium nitrate dissolving in water inside the pack)
C) thermite reaction between iron(III) oxide and aluminum (spectacular flames are observed)
D) freezing water to make ice cubes
E) none of the above are endothermic processes

Question 28

The specific heat capacity of gold is 0.13 J/g°C. How many calories of energy are needed to warm 0.570 g of gold from 30.0°C to 39.5°C?

A) 0.70 cal
B) 0.17 cal
C) 1.2 cal
D) 2.9 cal
E) 23 cal

Question 29

For the reaction Calculate the enthalpy change when 4.73 g of hydrogen gas is reacted with excess oxygen.

A) -60.5 kJ
B) 671 kJ
C) -671 kJ
D)
E) -

Question 30

____ is a flow of energy due to a temperature difference.

A) Heat
B) Radiation
C) Matter
D) Gravity
E) Work

Question 31

A 100.0 g sample of water at 27.0°C is poured into a 77.4 g sample of water at 89.0°C. What will be the final temperature of the water?

A) 88.7°C
B) 424°C
C) 23.6°C
D) 185°C
E) 54.1°C

Question 32

Perform the indicated conversion:

A) 686 J
B)
C) 12.0 J
D)
E)

Question 33

For the reaction What is the enthalpy change when 15.0 mol of hydrogen gas reacts with excess oxygen.

A) 19.1 kJ
B) -19.1 kJ
C)
D) -
E) -

Question 34

The law of conservation of energy states that energy can be converted from one form to another but can be neither created nor destroyed.

Question 35

Which of the following statements about energy is false?

A) A reaction cannot be exothermic overall if activation energy is required.
B) A system is the most stable when it is at its lowest energy state.
C) Energy can be defined as whatever is required to oppose a natural tendency.
D) Energy transferred into a system can also be transferred out of the system.
E) An atom in an excited state can return to its ground state by releasing visible light.

Question 36

The distance traveled from New York to Los Angeles is an example of a state function.

Question 37

Which of the following processes is exothermic?

A) rolling a ball up a hill
B) boiling water in a beaker to make steam
C) allowing meat to thaw after taking it out of the freezer
D) reacting hydrogen and oxygen gases to make water
E) a popsicle melting on a warm summer day

Question 38

Perform the indicated conversion: 7.079 kcal =____ kJ

A) 29.62 kJ
B) 1.692 kJ
C) 0.5910 kJ
D)
E)

Question 39

____ is the ability to do work or produce heat.

A) Gravity
B) Temperature
C) Radiation
D) Matter
E) Energy

Question 40

A 51.1-g sample of aluminum at 95.0°C is dropped into 35.0 g of water at 40.0°C. What is the final temperature of the mixture? (specific heat capacity of aluminum = 0.89 J/g°C; specific heat capacity of water = 4.184 J/g°C)

A) 53°C
B) -8.0°C
C) 101°C
D) 24°C
E) -15°C

Question 41

Enthalpy is not a state function.

Question 42

The calorie is defined as the amount of energy (heat) required to raise the temperature of one gram of water by one degree Celsius.

Question 43

The first law of ____ states that the energy of the universe is constant.

A) matter
B) mass
C) thermodynamics
D) motion
E) energy

Question 44

On a cold winter day, a steel metal fence post feels colder than a wooden fence post of identical size because

A) the specific heat capacity of steel is higher than the specific heat capacity of wood.
B) the specific heat capacity of steel is lower than the specific heat capacity of wood.
C) steel has the ability to resist a temperature change better than wood.
D) the mass of steel is less than wood, so it loses heat faster.
E) Two of the above statements are true.

Question 45

Consider the following processes: 167.4 341.4 -43.4 Calculate for the reaction

A) +217.5 kJ/mol
B) +130.2 kJ/mol
C) +108.7 kJ/mol
D) -217.5 kJ/mol
E) none of these

Question 46

Consider the reaction: When calculating the , why is the for not important?

A) Because nitrogen is in its standard elemental state, and no energy is needed for this product to exist.
B) Because any element or compound in the gaseous state requires a negligible amount of energy to exist.
C) Because the products are not included when calculating .
D) Because nitrogen is in its elemental state and does not contribute to the reaction itself.
E) Two of the above statements explain why N₂ is not important when calculating .

Question 47

____ was formed from the remains of plants that were buried and subjected to high pressure and heat over long periods of time.

A) Natural gas
B) Asphalt
C) Kerosene
D) Coal
E) Wood

Question 48

According to the first law of thermodynamics, the energy of the universe is constant. Does this mean that is always equal to zero?

A) Yes, at all times, which is why .
B) No, does not always equal zero, but this is due only to factors such as friction and heat.
C) No, does not always equal zero because it refers to the system's internal energy, which is affected by heat and work.
D) No, never equals zero because work is always being done on the system or by the system.
E) No, never equals zero because energy is always flowing between the system and surroundings.

Question 49

The greenhouse effect occurs only on the planet Earth.

Question 50

____ is a measure of disorder or randomness.

A) Entropy
B) Enthalpy
C) Calorimetry
D) Internal energy
E) Hess's law

Question 51

Consider the following standard heats of formation: Calculate the change in enthalpy for the following process:

A) +290 kJ
B) -290 kJ
C) -2117 kJ
D) +2117 kJ
E) -9942 kJ

Question 52

Consider the following reaction: Is the reaction exothermic or endothermic?

A) exothermic
B) endothermic

Question 53

In the equation , the q represents

A) work
B) change in energy
C) moles of a substance
D) mass of a substance
E) heat

Question 54

Consider the following standard heats of formation: Calculate the change in enthalpy for the following process:

A) 0 kJ
B) -655.6 kJ
C) +655.6 kJ
D) -131.4 kJ
E) +131.4 kJ

Question 55

Which of the following statements is/are true?
(I) q (heat) is a state function because ΔH is a state function and q=Δ .
(II) When 50.0 g of aluminum at 20.0°C is placed in 50.0 mL of water at 30.0°C, the H₂O will undergo a smaller temperature change than the aluminum. (density of H₂O = 1.0 g/ml , specific heat capacity of H₂O = 4.18 J/g.°C , specific heat capacity of aluminum = 0.89 J/g. °C)
III) When a gas is compressed, the work is negative since the surroundings is doing work on the system and energy flows out of the system.
(IV) For the reaction (at constant pressure) 2N₂(g)+5O₂(g) → 2N₂O₅(g) , the change in enthalpy is the same whether the reaction takes place in one step or in a series of steps.

A) I, II, IV
B) II, III
C) II, III, IV
D) II, IV
E) All of the above statements are true.