Calorimetry & Phase Changes

The specific heat of asphalt is 920 J/kg °C. How much heat energy is required to raise the temperature of 113 kilograms of asphalt 14°C?

1.46 × 106 J

Solid concrete has a specific heat of 0.920 J/g·°C. If 985 J of energy are added to a 100 g sample of concrete, how much will the temperature of the concrete increase?

10.7°C

The energy released by a chemical reaction can be measured using a calorimeter. When barium hydroxide octahydrate crystals are reacted with dry ammonium chloride inside of a coffee cup calorimeter, the temperature of the 18.00 g of water in the calorimeter decreases from 30.0°C to 8.0°C. If the specific heat of liquid water is 4.19 J/g·°C, how much energy was absorbed by the reaction?

1660 J

Examine the phase diagram shown below. Freezing occurs when a liquid changes into a solid. At what point does freezing occur?

2

Mumford has a sample of water, which has a specific heat of 4,186 J/kg °C. He adds 750,000 J of heat to it, and its temperature increases by 3.6°C. How much water is in his sample?

50 kg

A student performs a chemical reaction inside of a calorimeter. The energy released by the reaction increases the temperature of 35.00 g of water by 4.6°C. If the specific heat of liquid water is equal to 4.19 J/g·°C, how much energy was released by the chemical reaction?

670 J

A 34.00 kg sample of mud has a specific heat of 2,512 J/kg °C. If sunlight striking the mud supplies it with 604,084 J of energy, by how much does the mud's temperature increase?

7.07°C

It takes 41,500 J of energy to increase the temperature of 10 kg of sand by 5.0°C. What is the specific heat of the sand?

830 J/kg °C

Liquid water at room temperature has a specific heat capacity of 4.1813 J/g·K. The amount of heat required to produce a given change in temperature can be calculated using the following formula: q = mCpΔT where q is the heat energy, Cp is the specific heat, and ΔT is the change in temperature. Using this formula, how much energy would it take to increase the temperature of 100.0 grams of water by 2.00 K?

836 J

The table below shows data recorded in a heating experiment. MaterialMass of Sample (kg)Heat Added (J)Temperature Change (°C)Gold0.508,300129Copper0.508,30043.1Aluminum0.508,30018.5 From the data, what is the specific heat of aluminum?

897 J/kg °C

In order to change from a solid to a liquid or a liquid to a gas, water must absorb a large amount of heat energy. Water can absorb a large amount of energy while producing only small changes in temperature because water has a

high specific heat.

Examine the phase diagram shown below. What phase(s) of water exist at point 2?

I and II only

The table below shows data recorded in a heating experiment. MaterialMass of Sample (kg)Heat Added (J)Temperature Change (°C)Gold0.508,300129Copper0.508,30043.1Aluminum0.508,30018.5 Which of the following statements is true?

It takes more heat to raise a mass of aluminum's temperature 1°C than it takes to raise an equal mass of copper 1°C.

Objects A and B have the same mass but are made of different substances, and they are kept in thermal contact with each other. Object B was initially at a higher temperature than object A. When the objects reached thermal equilibrium, the temperature of object A was observed to have risen by 8°C, and the temperature of object B was observed to have dropped by 2°C. Assuming that there was no loss of thermal energy to the surroundings, which of the following conclusions is most consistent with these observations?

Object B has a higher specific heat capacity than object A.

Two pieces of pure copper, object X and object Y, are kept in thermal contact with each other. Object X is at a higher temperature than object Y. The mass of object X is 5 kg, and the mass of object Y is 8 kg. Assuming that there is no loss of thermal energy to the surroundings, which of the following statements correctly describes the two objects as they approach thermal equilibrium?

The drop in temperature of object X will be greater than the rise in temperature of object Y.

Examine the phase diagram shown below. At what points can water exist in more than one phase?

Water exists in more than one phase at the plateaus (2 and 4).

The graph below shows the boiling (vaporization) points for different substances that are liquids at 50°C.A beaker of plain water is being heated. When a thermometer reads 100°C, the kinetic energy of the particles inside the beaker will _______.

not change

LiquidSpecific Heat Capacity(J/g·°C)Benzol1.75Olive Oil1.96Sea Water3.93Kerosene2.00 It takes 392 J of energy to raise the temperature of a 5.00 g sample of an unknown liquid from 20°C to 60°C. Based on the table of values shown above, what is the identity of the unknown liquid?

olive oil

During a phase change, the temperature of a substance remains constant. This is because, during a phase change, heat changes the _______ energy of the particles in a substance without changing their _______ energy.

potential; kinetic

LiquidSpecific Heat Capacity(J/g·°C)Benzol1.75Olive Oil1.96Sea Water3.93Kerosene2.00 It takes 786 J of energy to raise the temperature of a 10.00 g sample of an unknown liquid from 25°C to 45°C. Based on the table of values shown above, what is the identity of the unknown liquid?

sea water