Question 1

Although CO is not toxic,there is concern that it causes global warming.

Accepted Answer

CO (carbon monoxide) is indeed toxic as it binds with hemoglobin in the blood, reducing the blood's ability to carry oxygen. The concern over global warming primarily involves CO2 (carbon dioxide), not CO.

Question 2

Choose the INCORRECT statement.

Accepted Answer

The specific heat is actually defined as the amount of heat per unit mass required to raise the temperature by one degree Celsius, not per mole of substance. The heat capacity per mole of substance is referred to as molar heat capacity.

Question 3

The standard enthalpy for diamond and graphite are the same value.

Accepted Answer

Diamond and graphite have different standard enthalpies because they are different forms (allotropes) of carbon with different crystal structures, leading to different enthalpies.

Question 4

The enthalpy of a system is the internal energy minus the pressure-volume product.

Accepted Answer

The enthalpy of a system is defined as the internal energy plus the pressure-volume product, not minus.

Question 5

Enthalpy is an extensive property.

Accepted Answer

Enthalpy is defined as the sum of internal energy of a system and the product of pressure and volume. It depends on the amount of substance present in the system, hence it is an extensive property.

Question 6

Choose the INCORRECT statement.

Accepted Answer

Potential energy is energy that is stored and has the potential to do work. It is not energy in action.

Question 7

1219 joules of heat raise the temperature of 250 g of metal by 64 °C.What is the specific heat of the metal in J/(g °C?)

Accepted Answer

The specific heat $c$ is calculated using the formula $c = \frac{q}{m\Delta T}$, where $q$ is the heat added, $m$ is the mass, and $\Delta T$ is the change in temperature. Substituting the given values, $c = \frac{1219}{250 \times 64}$ J/(g °C).

Question 8

A system that absorbs heat is an exothermic system.

Accepted Answer

A system that releases heat is exothermic, whereas a system that absorbs heat is endothermic.

Question 9

Lead,water,sulfur and arsenic have specific heats of 0.128,4.18,0.706,and 0.329 J g^-1 °C^-1,respectively.Which of the following would need the smallest quantity of heat to change the temperature of 5 g by 10 °C?

Accepted Answer

The heat required to change the temperature of a substance is given by the formula Q = mcΔT, where Q is the heat, m is the mass, c is the specific heat, and ΔT is the change in temperature.

Using this formula, we can calculate the heat required to change the temperature of 5 g of each substance by 10 °C:

- For lead: Q = (5 g)(0.128 J/g°C)(10°C) = 6.4 J
- For water: Q = (5 g)(4.18 J/g°C)(10°C) = 209 J
- For sulfur: Q = (5 g)(0.706 J/g°C)(10°C) = 35.3 J
- For arsenic: Q = (5 g)(0.329 J/g°C)(10°C) = 16.5 J

From these calculations, we can see that lead requires the smallest quantity of heat to change its temperature by 10 °C, with only 6.4 J of heat required. Therefore, the best choice is A) lead.

Question 10

The complete combustion of 1 mole of nitrobenzene,C₆H₅NO₂,in a bomb calorimeter liberates 3088 kJ of heat and increases the temperature of the calorimeter assembly by 140.0 °C.What is the heat capacity of this bomb calorimeter?

Accepted Answer

The heat capacity of the bomb calorimeter is given by: 
Ccal = Q/ΔT 
where Q is the heat released by the combustion of nitrobenzene and ΔT is the increase in temperature of the calorimeter.

From the problem, Q = 3088 kJ and ΔT = 140.0 °C. Therefore, 
Ccal = 3088 kJ / 140.0 °C = 22.1 kJ/ °C

Thus, the correct answer is (C).

Question 11

Heat is usually transferred from a cold object to a hot object.

Accepted Answer

Heat is transferred from a hot object to a cold object, according to the second law of thermodynamics. This occurs until the two objects reach thermal equilibrium, at which point heat transfer ceases.

Question 12

Kinetic energy is the energy of motion.

Accepted Answer

Kinetic energy is indeed the energy of motion.

Question 13

Choose the INCORRECT statement.

Accepted Answer

The surroundings are not a part of the universe that is studied, they are everything outside of the system being studied. The system is what is being studied.

Question 14

The maximum amount of work is provided by a reversible process because equilibrium between the system and the surroundings is always maintained.

Accepted Answer

In a reversible process, the system and the surroundings are always in equilibrium, which means that the maximum amount of work can be generated. This is because the system can be returned to its original state by reversing the process without leaving any trace on the surroundings. In an irreversible process, on the other hand, there is a net loss of energy and the system can't be returned to its original state. Therefore, the amount of work generated is lower than the maximum possible.

Question 15

An expansion of gas by a system means that the system does work.

Accepted Answer

This is a basic principle of thermodynamics that the expansion of a gas implies the system is doing work.

Question 16

What is the final temperature in the bomb calorimeter if 1.785 grams of benzoic acid (C₆H₅COOH)is combusted in a calorimeter with a heat capacity of 5.02 kJ/ °C and initial temperature of 24.62 °C? The heat of combustion of benzoic acid is -26.42 kJ/g.

Accepted Answer

The answer of What is the final temperature in the...

Question 17

A closed system can exchange matter but not energy with the surroundings.

Accepted Answer

A closed system can exchange energy but not matter with the surroundings.

Question 18

When power was turned off to a 30.0 gal.water heater,the temperature of the water dropped from 75.0 °C to 22.5 °C.How much heat was lost to the surroundings?

Accepted Answer

We can use the formula Q = mcΔT to calculate the heat lost, where Q is the heat lost, m is the mass of water, c is the specific heat capacity of water, and ΔT is the change in temperature.

First, we need to convert the volume of water to its mass. The density of water is 1 g/mL, or 1000 kg/m³. Therefore, 30.0 gallons = 113.562 L = 113.562 kg.

Next, we can plug in the values into the formula and solve for Q:

Q = (113.562 kg)(4.184 J/g°C)(75.0°C - 22.5°C) 
Q = 2.49 × 10¹⁴ J = 2.49 × 10⁴ kJ

The answer given in scientific notation is -2.49 × 10¹⁴ J, which means that the answer should be C, since it is the option closest to the calculated answer in kJ.

Question 19

14.0 g of metal at 24.0 °C has 250 joules of heat added to it.The metal's specific heat is 0.105 J/g °C.What is its final temperature?

Accepted Answer

First, we need to use the formula for heat (q) to calculate the change in temperature (ΔT) of the metal:

q = (m)(c)(ΔT)

where q = 250 J, m = 14.0 g, and c = 0.105 J/g °C.

Solving for ΔT, we get:

ΔT = q / (m)(c)
ΔT = 250 J / (14.0 g)(0.105 J/g °C)
ΔT ≈ 163.3 °C

Finally, we can use this value to determine the metal's final temperature:

Final temperature = Initial temperature + ΔT
Final temperature = 24.0 °C + 163.3 °C
Final temperature ≈ 187.3 °C

Therefore, the correct answer is C: [250 /(14.0)(0.105)] + 24.0 °C.

Question 20

An expansion of gas by a system means that the internal energy of the system increases.

Accepted Answer

An expansion of gas by a system means that the gas is performing work on its surroundings, which results in the decrease of the internal energy of the system. This is a manifestation of the First Law of Thermodynamics, which states that the change in internal energy of a system is given by the sum of the heat exchanged and the work performed on it.

Quiz 7: Thermochemistry

Although CO is not toxic,there is concern that it causes global warming.

Choose the INCORRECT statement.

The standard enthalpy for diamond and graphite are the same value.

The enthalpy of a system is the internal energy minus the pressure-volume product.

Enthalpy is an extensive property.

Choose the INCORRECT statement.

1219 joules of heat raise the temperature of 250 g of metal by 64 °C.What is the specific heat of the metal in J/(g °C?)

A system that absorbs heat is an exothermic system.

Lead,water,sulfur and arsenic have specific heats of 0.128,4.18,0.706,and 0.329 J g^-1 °C^-1,respectively.Which of the following would need the smallest quantity of heat to change the temperature of 5 g by 10 °C?

The complete combustion of 1 mole of nitrobenzene,C₆H₅NO₂,in a bomb calorimeter liberates 3088 kJ of heat and increases the temperature of the calorimeter assembly by 140.0 °C.What is the heat capacity of this bomb calorimeter?

Heat is usually transferred from a cold object to a hot object.

Kinetic energy is the energy of motion.

Choose the INCORRECT statement.

The maximum amount of work is provided by a reversible process because equilibrium between the system and the surroundings is always maintained.

An expansion of gas by a system means that the system does work.

What is the final temperature in the bomb calorimeter if 1.785 grams of benzoic acid (C₆H₅COOH) is combusted in a calorimeter with a heat capacity of 5.02 kJ/ °C and initial temperature of 24.62 °C? The heat of combustion of benzoic acid is -26.42 kJ/g.

A closed system can exchange matter but not energy with the surroundings.

When power was turned off to a 30.0 gal.water heater,the temperature of the water dropped from 75.0 °C to 22.5 °C.How much heat was lost to the surroundings?

14.0 g of metal at 24.0 °C has 250 joules of heat added to it.The metal's specific heat is 0.105 J/g °C.What is its final temperature?

An expansion of gas by a system means that the internal energy of the system increases.

Quiz 7: Thermochemistry

Although CO is not toxic,there is concern that it causes global warming.

Choose the INCORRECT statement.

The standard enthalpy for diamond and graphite are the same value.

The enthalpy of a system is the internal energy minus the pressure-volume product.

Enthalpy is an extensive property.

Choose the INCORRECT statement.

1219 joules of heat raise the temperature of 250 g of metal by 64 °C.What is the specific heat of the metal in J/(g °C?)

A system that absorbs heat is an exothermic system.

Lead,water,sulfur and arsenic have specific heats of 0.128,4.18,0.706,and 0.329 J g-1 °C-1,respectively.Which of the following would need the smallest quantity of heat to change the temperature of 5 g by 10 °C?

The complete combustion of 1 mole of nitrobenzene,C6H5NO2,in a bomb calorimeter liberates 3088 kJ of heat and increases the temperature of the calorimeter assembly by 140.0 °C.What is the heat capacity of this bomb calorimeter?

Heat is usually transferred from a cold object to a hot object.

Kinetic energy is the energy of motion.

Choose the INCORRECT statement.

The maximum amount of work is provided by a reversible process because equilibrium between the system and the surroundings is always maintained.

An expansion of gas by a system means that the system does work.

What is the final temperature in the bomb calorimeter if 1.785 grams of benzoic acid (C6H5COOH) is combusted in a calorimeter with a heat capacity of 5.02 kJ/ °C and initial temperature of 24.62 °C? The heat of combustion of benzoic acid is -26.42 kJ/g.

A closed system can exchange matter but not energy with the surroundings.

When power was turned off to a 30.0 gal.water heater,the temperature of the water dropped from 75.0 °C to 22.5 °C.How much heat was lost to the surroundings?

14.0 g of metal at 24.0 °C has 250 joules of heat added to it.The metal's specific heat is 0.105 J/g °C.What is its final temperature?

An expansion of gas by a system means that the internal energy of the system increases.

Lead,water,sulfur and arsenic have specific heats of 0.128,4.18,0.706,and 0.329 J g^-1 °C^-1,respectively.Which of the following would need the smallest quantity of heat to change the temperature of 5 g by 10 °C?

The complete combustion of 1 mole of nitrobenzene,C₆H₅NO₂,in a bomb calorimeter liberates 3088 kJ of heat and increases the temperature of the calorimeter assembly by 140.0 °C.What is the heat capacity of this bomb calorimeter?

What is the final temperature in the bomb calorimeter if 1.785 grams of benzoic acid (C₆H₅COOH) is combusted in a calorimeter with a heat capacity of 5.02 kJ/ °C and initial temperature of 24.62 °C? The heat of combustion of benzoic acid is -26.42 kJ/g.