If 75.4 J of energy is absorbed by 0.25 mol of CCl4 at constant pressure, what is the change in temperature? The specific heat of CCl4 is 0.861 J/g·°C.

A) 17.8°C B) 21.9°C C) 2.3°C D) 9.1°C E) 44.6°C A) 17.8°C B) 21.9°C C) 2.3°C D) 9.1°C E) 44.6°C

Exam 5: Thermochemistry

Two solutions (the system), each with a volume of 25.0 mL at 25.0°C, are mixed in a beaker. A reaction occurs between them, and the temperature rises to 35.0°C. After the products have equilibrated with the surroundings, the temperature is again 25.0°C and the total volume is 50.0 mL. No gases are involved in the reaction. Which relationship concerning the change from initial to final states (both at 25.0°C) is correct?

(Multiple Choice)

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Question 21

Naphthalene combustion may be used to calibrate the heat capacity of a bomb calorimeter. The heat of combustion of naphthalene is -40.1 kJ/g. When 0.8210 g of naphthalene was burned in a bomb calorimeter containing 1.000 kg of water, a temperature rise of 4.21°C was observed. What is the heat capacity of the bomb calorimeter excluding the water?

(Multiple Choice)

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Question 22

If 75.4 J of energy is absorbed by 0.25 mol of CCl₄ at constant pressure, what is the change in temperature? The specific heat of CCl₄ is 0.861 J/g·°C.

(Multiple Choice)

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Question 23

When an automobile engine starts, the metal parts immediately begin to absorb heat released during the combustion of gasoline. How much heat will be absorbed by a 165-kg iron engine block when the temperature rises from 15.7°C to 95.7°C? (The specific heat of iron is 0.489 J/g·°C.)

(Short Answer)

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Question 24

Which of these is not a state function?

(Multiple Choice)

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Question 25

Internal energy = +

(Short Answer)

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Question 26

Which represents an enthalpy change at 25 °C and 1 atm that is equal to ΔH^o_ffor H₂O(l)?

(Multiple Choice)

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Question 27

A(n) is a process where heat is absorbed from the surroundings.

(Short Answer)

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Question 28

What is q if 28.6 g of water is heated from 22.0°C to 78.3°C? The specific heat of water is 4.184 J/g·°C.

(Multiple Choice)

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Question 29

Based on the following thermochemical equations, what is the heat of vaporization of titanium(IV) chloride? Ti(s) + 2 Cl₂(g) → TiCl₄(l) ΔH = -804.2 kJ/mol TiCl₄(g) → 2 Cl₂(g) + Ti(s) ΔH = 763.2 kJ/mol

(Multiple Choice)

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Question 30

Thunderstorms are powered by the heat released when water vapor changes to rain drops. How much heat is released when a gallon of rain falls? (1 gal = 3,785 g; specific heat of vaporization of water = 2,262 J/g)

(Short Answer)

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Question 31

The enthalpy change for making one mole of a compound from its elements is called the ________.

(Short Answer)

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Question 32

Suppose a 0.500-g sample of an organic compound is analyzed via bomb calorimetry. The temperature of the calorimeter is measured over time. At t = 5 min, the combustion reaction is initiated. Below is a plot of the data that are obtained. Suppose the experiment is repeated under identical conditions, but with a 1.000-g sample of the organic compound. What might a plot of the resulting data look like?

(Multiple Choice)

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Question 33

A system delivers 1275 J of heat while the surroundings perform 854 J of work on it. What is ΔU of the system?

(Multiple Choice)

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Question 34

Which of the following is incorrectly matched?

(Multiple Choice)

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Question 35

What is the change in temperature if a 25.0-g block of aluminum absorbs 10.0 kJ of heat? The specific heat of aluminum is 0.900 J/g·°C.

(Multiple Choice)

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Question 36

At body temperature 2404 joules of energy are required to evaporate 1.00 g of water. After vigorous exercise, a person feels chilly because the body is giving up heat to evaporate the perspiration. A typical person perspires 25 mL of water after 20. minutes of exercise. How much body heat is this person using to evaporate this water?

(Short Answer)

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Question 37

A home aquarium is an example of an open system.

(True/False)

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Question 38

The sign of w when work is done by the system on the surroundings is ________.

(Short Answer)

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Question 39

A system expands from a volume of 1.00 L to 2.00 L against a constant external pressure of 1.00 atm. What is the work (w) done by the system? (1 L·atm = 101.3 J)

(Multiple Choice)

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Question 40

Showing 21 - 40 of 141

Exam 5: Thermochemistry

If 75.4 J of energy is absorbed by 0.25 mol of CCl4 at constant pressure, what is the change in temperature? The specific heat of CCl4 is 0.861 J/g·°C.

When an automobile engine starts, the metal parts immediately begin to absorb heat released during the combustion of gasoline. How much heat will be absorbed by a 165-kg iron engine block when the temperature rises from 15.7°C to 95.7°C? (The specific heat of iron is 0.489 J/g·°C.)

Which of these is not a state function?

Internal energy = ________ + ________

Which represents an enthalpy change at 25 °C and 1 atm that is equal to ΔHof for H2O(l)?

A(n) ________ ________ is a process where heat is absorbed from the surroundings.

What is q if 28.6 g of water is heated from 22.0°C to 78.3°C? The specific heat of water is 4.184 J/g·°C.

Based on the following thermochemical equations, what is the heat of vaporization of titanium(IV) chloride? Ti(s) + 2 Cl2(g) → TiCl4(l) ΔH = -804.2 kJ/mol TiCl4(g) → 2 Cl2(g) + Ti(s) ΔH = 763.2 kJ/mol

Thunderstorms are powered by the heat released when water vapor changes to rain drops. How much heat is released when a gallon of rain falls? (1 gal = 3,785 g; specific heat of vaporization of water = 2,262 J/g)

The enthalpy change for making one mole of a compound from its elements is called the ________.

A system delivers 1275 J of heat while the surroundings perform 854 J of work on it. What is ΔU of the system?

Which of the following is incorrectly matched?

What is the change in temperature if a 25.0-g block of aluminum absorbs 10.0 kJ of heat? The specific heat of aluminum is 0.900 J/g·°C.

A home aquarium is an example of an open system.

The sign of w when work is done by the system on the surroundings is ________.

A system expands from a volume of 1.00 L to 2.00 L against a constant external pressure of 1.00 atm. What is the work (w) done by the system? (1 L·atm = 101.3 J)

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If 75.4 J of energy is absorbed by 0.25 mol of CCl₄ at constant pressure, what is the change in temperature? The specific heat of CCl₄ is 0.861 J/g·°C.

Internal energy = +

Which represents an enthalpy change at 25 °C and 1 atm that is equal to ΔH^o_ffor H₂O(l)?

A(n) is a process where heat is absorbed from the surroundings.

Based on the following thermochemical equations, what is the heat of vaporization of titanium(IV) chloride? Ti(s) + 2 Cl₂(g) → TiCl₄(l) ΔH = -804.2 kJ/mol TiCl₄(g) → 2 Cl₂(g) + Ti(s) ΔH = 763.2 kJ/mol