Question 1

A 5.00-g sample of copper metal at 25.0 °C is heated by the addition of 133 J of energy. The final temperature of the copper is ________°C. The specific heat capacity of copper is 0.38 J/g-K.

Accepted Answer

The answer of A 5.00-g sample of copper metal at...

Question 2

The specific heat capacity of methane gas is 2.20 J/g-K. How many joules of heat are needed to raise the temperature of 7.25 g of methane from 22.0 °C to 57.0 °C?

Accepted Answer

The equation to calculate the amount of heat (q) needed to raise the temperature of a substance is: 
q = m * c * ΔT 
where 
m = mass of substance 
c = specific heat capacity of substance 
ΔT = change in temperature

Plugging in the values given in the question, we get: 
q = 7.25 g * 2.20 J/g-K * (57.0°C - 22.0°C) 
q = 558 J

Therefore, the answer is B.

Question 3

In the presence of excess oxygen, methane gas burns in a constant-pressure system to yield carbon dioxide and water: CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (l)△H = -890.0 kJ Calculate the value of q (kJ)in this exothermic reaction when 1.80 g of methane is combusted at constant pressure.

Accepted Answer

1. First, we need to calculate the amount of heat released when 1.80 g of methane is burned. We can use the balanced chemical equation and the given enthalpy change to do this:

- 1 mole of CH4 produces -890.0 kJ of heat
- The molar mass of CH4 is 16.04 g/mol

Using these values, we can set up the following proportion to find the amount of heat released when 1.80 g of CH4 is burned:

(1.80 g CH4) / (16.04 g/mol) x (-890.0 kJ/mol) = -100.1 kJ

Note that the negative sign indicates that the reaction is exothermic and releases heat.

2. Therefore, the correct answer is A) -100.1 kJ.

Question 4

An 6.11 g sample of calcium carbonate [CaCO₃ (s)] absorbs 84 J of heat, upon which the temperature of the sample increases from 19.2 °C to 35.9 °C. What is the specific heat of calcium carbonate?

Accepted Answer

The specific heat (c) can be calculated using the formula q = mcΔT, where q is the heat absorbed (84 J), m is the mass (6.11 g), and ΔT is the temperature change (35.9 °C - 19.2 °C = 16.7 °C). Solving for c gives c = q / (mΔT) = 84 J / (6.11 g * 16.7 K) = 0.82 J/g-K.

Question 5

A 4.50-g sample of liquid water at 25.0 °C is heated by the addition of 133 J of energy. The final temperature of the water is ________ °C. The specific heat capacity of liquid water is 4.18 J/g-K.

Accepted Answer

First, we need to use the equation:

q = mcΔT

where q is the energy added, m is the mass of water, c is the specific heat capacity of water, and ΔT is the change in temperature.

Rearranging the equation to solve for ΔT:

ΔT = q / mc

Plugging in the given values:

m = 4.50 g

c = 4.18 J/g-K

q = 133 J

ΔT = (133 J) / (4.50 g x 4.18 J/g-K) = 7.07 K

Since the initial temperature was 25.0 °C, the final temperature will be:

Final temperature = Initial temperature + ΔT = 25.0 °C + 7.07 K = 32.1 °C

Therefore, the best choice is D.

Question 6

The temperature of a 35.1 g sample of iron increases from 24.5 °C to 31.8 °C. If the specific heat of iron is 0.450 J/g-K, how many joules of heat are absorbed?

Accepted Answer

We can use the formula Q = mcΔT, where Q is the amount of heat absorbed, m is the mass of the substance (in grams), c is the specific heat (in J/g-K), and ΔT is the change in temperature (in K or °C).

Substituting the given values, we get:

Q = (35.1 g)(0.450 J/g-K)(31.8 °C - 24.5 °C)
Q = (35.1 g)(0.450 J/g-K)(7.3 °C)
Q = 115 J

Therefore, the answer is A) 115 J, which represents the amount of heat absorbed by the iron sample.

Question 7

The ΔH for the solution process when solid sodium hydroxide dissolves in water is 44.4 kJ/mol. When a 12.6-g sample of NaOH dissolves in 250.0 g of water in a coffee-cup calorimeter, the temperature increases from 23.0 °C to ________°C. Assume that the solution has the same specific heat as liquid water, i.e., 4.18 J/g-K.

Accepted Answer

The heat absorbed by the solution can be calculated using q = m × c × ΔT. First, convert 12.6 g of NaOH to moles (12.6 g / 40.0 g/mol = 0.315 mol). The heat released is 0.315 mol × 44.4 kJ/mol = 13.986 kJ = 13986 J. The total mass of the solution is 12.6 g + 250.0 g = 262.6 g. Using q = m × c × ΔT, we have 13986 J = 262.6 g × 4.18 J/g-K × ΔT. Solving for ΔT gives ΔT = 12.7°C. The final temperature is 23.0°C + 12.7°C = 35.7°C.

Question 8

The combustion of titanium with oxygen produces titanium dioxide: Ti (s)+ O₂ (g) → TiO₂ (s) When 0.610 g of titanium is combusted in a bomb calorimeter, the temperature of the calorimeter increases from 25.00 °C to 50.50 °C. In a separate experiment, the heat capacity of the calorimeter is measured to be 9.84 kJ/K. The heat of reaction for the combustion of a mole of Ti in this calorimeter is ________ kJ/mol.

Accepted Answer

The answer of The combustion of titanium with oxygen produces...

Question 9

The specific heat capacity of liquid mercury is 0.14 J/g-K. How many joules of heat are needed to raise the temperature of 6.00 g of mercury from 25.1 °C to 65.3 °C?

Accepted Answer

The answer of The specific heat capacity of liquid mercury...

Question 10

Hydrogen peroxide decomposes to water and oxygen at constant pressure by the following reaction: 2H₂O₂ (l) → 2H₂O (l)+ O₂ (g)△H = -196 kJ Calculate the value of q (kJ)in this exothermic reaction when 1.50 g of hydrogen peroxide decomposes at constant pressure?

Accepted Answer

The molar mass of H₂O₂ is 34.01 g/mol. For 1.50 g of H₂O₂, moles = 1.50 g / 34.01 g/mol = 0.0441 mol. The reaction releases 196 kJ for 2 moles of H₂O₂, so for 0.0441 mol, q = (196 kJ / 2 mol) * 0.0441 mol = -4.32 kJ.

Question 11

A 22.9 g sample of iron absorbs 155 J of heat, upon which the temperature of the sample increases from 23.9 °C to 38.9 °C. What is the specific heat of iron?

Accepted Answer

The specific heat (c) can be calculated using the formula q = mcΔT, where q is the heat absorbed (155 J), m is the mass (22.9 g), and ΔT is the change in temperature (38.9 °C - 23.9 °C = 15.0 °C). Solving for c gives c = q / (mΔT) = 155 J / (22.9 g * 15.0 °C) = 0.451 J/g-K.

Question 12

The temperature of a 11.8 g sample of calcium carbonate [CaCO₃ (s)] increases from 24.8 °C to 38.0 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, how many joules of heat are absorbed?

Accepted Answer

The heat absorbed can be calculated using the formula q = m*c*ΔT, where m is mass, c is specific heat, and ΔT is the change in temperature. Substituting the given values: q = 11.8 g * 0.82 J/g-K * (38.0 °C - 24.8 °C) = 130 J.

Question 13

A sample of calcium carbonate [CaCO₃ (s)] absorbs 40.3 J of heat, upon which the temperature of the sample increases from 20.8 °C to 27.3 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, what is the mass (in grams)of the sample?

Accepted Answer

Using the formula q = mcΔT, where q is the heat absorbed (40.3 J), m is the mass, c is the specific heat (0.82 J/g-K), and ΔT is the change in temperature (27.3 °C - 20.8 °C = 6.5 °C), we can solve for m: m = q / (cΔT) = 40.3 J / (0.82 J/g-K * 6.5 K) = 7.6 g.

Question 14

What is the enthalpy change (in kJ)of a chemical reaction that raises the temperature of 250.0 mL of solution having a density of 1.25 g/mL by 3.33 °C? (The specific heat of the solution is 3.74 J/g-K.)

Accepted Answer

The answer of What is the enthalpy change (in kJ)of...

Question 15

The temperature of a 24.3 g sample of gold increases from 23.7 °C to 31.5 °C. If the specific heat of gold is 0.129 J/g-K, how many joules of heat are absorbed?

Accepted Answer

The heat absorbed (q) can be calculated using the formula q = m * c * ΔT, where m is the mass (24.3 g), c is the specific heat (0.129 J/g-K), and ΔT is the change in temperature (31.5 °C - 23.7 °C = 7.8 °C). Plugging in the values, q = 24.3 g * 0.129 J/g-K * 7.8 K = 24.5 J.

Question 16

A 50.0-g sample of liquid water at 25.0 °C is mixed with 23.0 g of water at 79.0 °C. The final temperature of the water is ________ °C.

Accepted Answer

The final temperature can be found using the principle of conservation of energy, where the heat lost by the hot water equals the heat gained by the cold water. Since both substances are water, their specific heat capacities are the same, and thus, the calculation simplifies. The final temperature is a weighted average of the initial temperatures, taking into account the masses of the two water samples.

Question 17

A sample of aluminum metal absorbs 11.2 J of heat, upon which the temperature of the sample increases from 23.2 °C to 30.5 °C. Since the specific heat capacity of aluminum is 0.90 J/g-K, the mass of the sample is ________ g.

Accepted Answer

We can use the formula:

q = m * C * ΔT

where q is the heat absorbed, m is the mass of the sample, C is the specific heat capacity, and ΔT is the change in temperature.

Substituting the given values, we get:

11.2 J = m * 0.90 J/g-K * (30.5 °C - 23.2 °C)

Simplifying, we get:

11.2 J = m * 6.53 J/g

m = 1.7 g

Therefore, the mass of the sample is 1.7 g. The correct answer is (B).

Question 18

A sample of iron absorbs 81.0 J of heat, upon which the temperature of the sample increases from 19.7 °C to 28.2 °C. If the specific heat of iron is 0.450 J/g-K, what is the mass (in grams)of the sample?

Accepted Answer

The formula to calculate the mass is: q = m * c * ΔT. Rearranging for m gives m = q / (c * ΔT). Here, q = 81.0 J, c = 0.450 J/g-K, and ΔT = 28.2 °C - 19.7 °C = 8.5 K. So, m = 81.0 J / (0.450 J/g-K * 8.5 K) = 21.2 g.

Question 19

The specific heat capacity of solid copper metal is 0.385 J/g-K. How many joules of heat are needed to raise the temperature of a 2.12-kg block of copper from 25.0 °C to 99.9 °C?

Accepted Answer

We can use the formula:

Q = m c ΔT

where Q is the heat transferred, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.

Plugging in the values, we get:

Q = (2.12 kg)(0.385 J/g-K)(99.9 °C - 25.0 °C) 
Q = 6.11 × 10^4 J

Therefore, the answer is (C).

Question 20

The specific heat capacity of liquid water is 4.18 J/g-K. How many joules of heat are needed to raise the temperature of 7.25 g of water from 20.0 °C to 44.1 °C?

Accepted Answer

The answer of The specific heat capacity of liquid water...

Quiz 5: Thermochemistry

A 5.00-g sample of copper metal at 25.0 °C is heated by the addition of 133 J of energy. The final temperature of the copper is ________°C. The specific heat capacity of copper is 0.38 J/g-K.

The specific heat capacity of methane gas is 2.20 J/g-K. How many joules of heat are needed to raise the temperature of 7.25 g of methane from 22.0 °C to 57.0 °C?

In the presence of excess oxygen, methane gas burns in a constant-pressure system to yield carbon dioxide and water: CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (l) △H = -890.0 kJ Calculate the value of q (kJ) in this exothermic reaction when 1.80 g of methane is combusted at constant pressure.

An 6.11 g sample of calcium carbonate [CaCO₃ (s) ] absorbs 84 J of heat, upon which the temperature of the sample increases from 19.2 °C to 35.9 °C. What is the specific heat of calcium carbonate?

A 4.50-g sample of liquid water at 25.0 °C is heated by the addition of 133 J of energy. The final temperature of the water is ________ °C. The specific heat capacity of liquid water is 4.18 J/g-K.

The temperature of a 35.1 g sample of iron increases from 24.5 °C to 31.8 °C. If the specific heat of iron is 0.450 J/g-K, how many joules of heat are absorbed?

The specific heat capacity of liquid mercury is 0.14 J/g-K. How many joules of heat are needed to raise the temperature of 6.00 g of mercury from 25.1 °C to 65.3 °C?

Hydrogen peroxide decomposes to water and oxygen at constant pressure by the following reaction: 2H₂O₂ (l) → 2H₂O (l) + O₂ (g) △H = -196 kJ Calculate the value of q (kJ) in this exothermic reaction when 1.50 g of hydrogen peroxide decomposes at constant pressure?

A 22.9 g sample of iron absorbs 155 J of heat, upon which the temperature of the sample increases from 23.9 °C to 38.9 °C. What is the specific heat of iron?

The temperature of a 11.8 g sample of calcium carbonate [CaCO₃ (s) ] increases from 24.8 °C to 38.0 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, how many joules of heat are absorbed?

A sample of calcium carbonate [CaCO₃ (s) ] absorbs 40.3 J of heat, upon which the temperature of the sample increases from 20.8 °C to 27.3 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, what is the mass (in grams) of the sample?

What is the enthalpy change (in kJ) of a chemical reaction that raises the temperature of 250.0 mL of solution having a density of 1.25 g/mL by 3.33 °C? (The specific heat of the solution is 3.74 J/g-K.)

The temperature of a 24.3 g sample of gold increases from 23.7 °C to 31.5 °C. If the specific heat of gold is 0.129 J/g-K, how many joules of heat are absorbed?

A 50.0-g sample of liquid water at 25.0 °C is mixed with 23.0 g of water at 79.0 °C. The final temperature of the water is ________ °C.

A sample of aluminum metal absorbs 11.2 J of heat, upon which the temperature of the sample increases from 23.2 °C to 30.5 °C. Since the specific heat capacity of aluminum is 0.90 J/g-K, the mass of the sample is ________ g.

A sample of iron absorbs 81.0 J of heat, upon which the temperature of the sample increases from 19.7 °C to 28.2 °C. If the specific heat of iron is 0.450 J/g-K, what is the mass (in grams) of the sample?

The specific heat capacity of solid copper metal is 0.385 J/g-K. How many joules of heat are needed to raise the temperature of a 2.12-kg block of copper from 25.0 °C to 99.9 °C?

The specific heat capacity of liquid water is 4.18 J/g-K. How many joules of heat are needed to raise the temperature of 7.25 g of water from 20.0 °C to 44.1 °C?

Quiz 5: Thermochemistry

A 5.00-g sample of copper metal at 25.0 °C is heated by the addition of 133 J of energy. The final temperature of the copper is ________°C. The specific heat capacity of copper is 0.38 J/g-K.

The specific heat capacity of methane gas is 2.20 J/g-K. How many joules of heat are needed to raise the temperature of 7.25 g of methane from 22.0 °C to 57.0 °C?

In the presence of excess oxygen, methane gas burns in a constant-pressure system to yield carbon dioxide and water: CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (l) △H = -890.0 kJ Calculate the value of q (kJ) in this exothermic reaction when 1.80 g of methane is combusted at constant pressure.

An 6.11 g sample of calcium carbonate [CaCO3 (s) ] absorbs 84 J of heat, upon which the temperature of the sample increases from 19.2 °C to 35.9 °C. What is the specific heat of calcium carbonate?

A 4.50-g sample of liquid water at 25.0 °C is heated by the addition of 133 J of energy. The final temperature of the water is ________ °C. The specific heat capacity of liquid water is 4.18 J/g-K.

The temperature of a 35.1 g sample of iron increases from 24.5 °C to 31.8 °C. If the specific heat of iron is 0.450 J/g-K, how many joules of heat are absorbed?

The specific heat capacity of liquid mercury is 0.14 J/g-K. How many joules of heat are needed to raise the temperature of 6.00 g of mercury from 25.1 °C to 65.3 °C?

Hydrogen peroxide decomposes to water and oxygen at constant pressure by the following reaction: 2H2O2 (l) → 2H2O (l) + O2 (g) △H = -196 kJ Calculate the value of q (kJ) in this exothermic reaction when 1.50 g of hydrogen peroxide decomposes at constant pressure?

A 22.9 g sample of iron absorbs 155 J of heat, upon which the temperature of the sample increases from 23.9 °C to 38.9 °C. What is the specific heat of iron?

The temperature of a 11.8 g sample of calcium carbonate [CaCO3 (s) ] increases from 24.8 °C to 38.0 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, how many joules of heat are absorbed?

A sample of calcium carbonate [CaCO3 (s) ] absorbs 40.3 J of heat, upon which the temperature of the sample increases from 20.8 °C to 27.3 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, what is the mass (in grams) of the sample?

What is the enthalpy change (in kJ) of a chemical reaction that raises the temperature of 250.0 mL of solution having a density of 1.25 g/mL by 3.33 °C? (The specific heat of the solution is 3.74 J/g-K.)

The temperature of a 24.3 g sample of gold increases from 23.7 °C to 31.5 °C. If the specific heat of gold is 0.129 J/g-K, how many joules of heat are absorbed?

A 50.0-g sample of liquid water at 25.0 °C is mixed with 23.0 g of water at 79.0 °C. The final temperature of the water is ________ °C.

A sample of aluminum metal absorbs 11.2 J of heat, upon which the temperature of the sample increases from 23.2 °C to 30.5 °C. Since the specific heat capacity of aluminum is 0.90 J/g-K, the mass of the sample is ________ g.

A sample of iron absorbs 81.0 J of heat, upon which the temperature of the sample increases from 19.7 °C to 28.2 °C. If the specific heat of iron is 0.450 J/g-K, what is the mass (in grams) of the sample?

The specific heat capacity of solid copper metal is 0.385 J/g-K. How many joules of heat are needed to raise the temperature of a 2.12-kg block of copper from 25.0 °C to 99.9 °C?

The specific heat capacity of liquid water is 4.18 J/g-K. How many joules of heat are needed to raise the temperature of 7.25 g of water from 20.0 °C to 44.1 °C?

In the presence of excess oxygen, methane gas burns in a constant-pressure system to yield carbon dioxide and water: CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (l) △H = -890.0 kJ Calculate the value of q (kJ) in this exothermic reaction when 1.80 g of methane is combusted at constant pressure.

An 6.11 g sample of calcium carbonate [CaCO₃ (s) ] absorbs 84 J of heat, upon which the temperature of the sample increases from 19.2 °C to 35.9 °C. What is the specific heat of calcium carbonate?

Hydrogen peroxide decomposes to water and oxygen at constant pressure by the following reaction: 2H₂O₂ (l) → 2H₂O (l) + O₂ (g) △H = -196 kJ Calculate the value of q (kJ) in this exothermic reaction when 1.50 g of hydrogen peroxide decomposes at constant pressure?

The temperature of a 11.8 g sample of calcium carbonate [CaCO₃ (s) ] increases from 24.8 °C to 38.0 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, how many joules of heat are absorbed?

A sample of calcium carbonate [CaCO₃ (s) ] absorbs 40.3 J of heat, upon which the temperature of the sample increases from 20.8 °C to 27.3 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, what is the mass (in grams) of the sample?