Q: A 200 g piece of iron at $$120^\circC $$and a 150 g piece of copper at $$-50^\circC $$are dropped into an insulated beaker containing 300 g of ethyl alcohol at $$20^\circC. $$What equation would you use to find the final temperature $$T_f$$?

$$0.200 \times 449 \times (T_f - 120) + 0.150 \times 385 \times (T_f + 50) + 0.300 \times 2400 \times (T_f - 20) = 0$$

Q: A 500 mL soda at $$20^\circC $$has 100 g of ice at $$-20^\circC $$added to it. The specific heat of soda is $$4190 J/kg-K$$, and the specific heat of ice is $$2090 J/kg-K. $$The latent heat of fusion for ice is $$3.33 \times 10^5$ J/kg. What is the total energy required to bring the ice to 0$$^\circ$$C and melt it completely?

$$0.100 \times 2090 \times 20 + 0.100 \times 3.33 \times 10^5$ = 37500 J$$

Question 1

Which of the following best describes the principle of calorimetry?

Accepted Answer

The heat lost by the hot body is equal to the heat gained by the cold body.

Question 2

A 200 g piece of iron at $$120^\circC $$and a 150 g piece of copper at $$-50^\circC $$are dropped into an insulated beaker containing 300 g of ethyl alcohol at $$20^\circC. $$What equation would you use to find the final temperature $$T_f$$?

Accepted Answer

$$0.200 	imes 449 	imes (T_f - 120) + 0.150 	imes 385 	imes (T_f + 50) + 0.300 	imes 2400 	imes (T_f - 20) = 0$$

Question 3

Which assumption is NOT typically made in calorimetry experiments?

Accepted Answer

The calorimeter absorbs some heat during the reaction.

Question 4

In a calorimetry experiment, 30 g of copper pellets are removed from a $$300^\circC $$oven and dropped into 100 mL of water at $$20^\circC. $$Which equation would you use to solve for the final temperature?

Accepted Answer

$$m_{Cu}c$$_{Cu}(T_{final} - 300) + $$m_{H_2O}c$$_{H_2O}(T_{final} - 20) = 0$$

Question 5

Which of the following is a limitation of calorimetry?

Accepted Answer

Energy may be transferred to or from the environment, leading to heat loss.

Question 6

Which type of calorimetry involves measuring oxygen consumption or carbon dioxide production to estimate energy change?

Accepted Answer

Indirect calorimetry

Question 7

A polystyrene cup calorimeter is used to determine the enthalpy change of a reaction. Which formula is used to calculate the enthalpy change?

Accepted Answer

$$\Delta H = -mc\Delta T$$

Question 8

Which of the following is a real-world application of calorimetry?

Accepted Answer

Determining the calorie content of foods in food laboratories.

Question 9

In a calorimetry experiment, why is a polystyrene cup often used as the calorimeter?

Accepted Answer

It acts as a good thermal insulator, minimizing heat exchange with the environment.

Question 10

A 500 mL soda at $$20^\circC $$has 100 g of ice at $$-20^\circC $$added to it. The specific heat of soda is $$4190 J/kg-K$$, and the specific heat of ice is $$2090 J/kg-K. $$The latent heat of fusion for ice is $$3.33 	imes 10^5$ J/kg. What is the total energy required to bring the ice to 0$$^\circ$$C and melt it completely?

Accepted Answer

$$0.100 	imes 2090 	imes 20 + 0.100 	imes 3.33 	imes 10^5$ = 37500 J$$

Question 11

Which of the following best describes differential scanning calorimetry (DSC)?

Accepted Answer

It measures the energy required to raise the temperature of a sample and a reference by the same amount.

Question 12

Which equation would you use to calculate the energy released by burning a known mass of propan-1-ol in a calorimeter?

Accepted Answer

$$\Delta H = -mc\Delta T$$

Question 13

Which of the following is NOT a typical application of calorimetry?

Accepted Answer

Measuring the electrical conductivity of metals.

Question 14

In an experiment, a 750 g aluminum pan is plunged into 10.0 L of water at $$20.0^\circC$$, and the water temperature rises to $$24.0^\circC. $$Which variable would you solve for to find the initial temperature of the pan?

Accepted Answer

The initial temperature of the aluminum pan.

Question 15

Which of the following is a key advantage of indirect calorimetry over direct calorimetry?

Accepted Answer

It is much cheaper and easier to carry out.

Question 16

A metal sphere weighing 450 g is heated to $$250^\circC $$and dropped into 330 cm$$^3 of $$mercury at $$24^\circC. $$The temperature stabilizes at $$95.0^\circC. $$Which property would you use to identify the metal?

Accepted Answer

The specific heat capacity of the metal.

Question 17

Which of the following is a disadvantage of indirect calorimetry?

Accepted Answer

It is not as accurate as direct calorimetry.

Question 18

Which of the following best explains why a calorimeter should be well-insulated?

Accepted Answer

To minimize heat exchange with the environment and improve accuracy.

Question 19

In a calorimetry experiment, why is it important to stir the mixture?

Accepted Answer

To ensure uniform temperature distribution throughout the solution.

Calorimetry: Principles, Types, and Applications

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