FORM3 PHY HEAT ENERGY AND GAS LAWS

1. Using an electric kettle, 200 g of water at 100 ‹C is converted into steam at 100 ‹C in 300 seconds.The specific latent heat of steam is 2250 J / g. What is the average electrical power used?

2.. The specific heat of liquid bromine is 0.226 J/g-K. How much heat (J) is required to raise the temperature of 10.0 mL of bromine from 25.00 °C to 27.30 °C? The density of liquid bromine: 3.12 g/cm³.

A) 5.20

B) 16.2

C) 300

D) 32.4

3. . A sample of iron absorbs 67.5 J of heat, upon which the temperature of the sample increases from 21.5 °C to 28.5 °C. If the specific heat of iron is 0.450 J/g-K, what is the mass (in grams) of the sample?

A) 4.3

B) 11

C) 21

D) 1100

4. The specific latent heat of vaporization of a substance is the quantity of energy required to

A. raise the temperature of a unit mass of a substance by one degree Celsius

B. convert a unit mass of liquid to vapour at constant temperature and pressure.

C. convert a unit mass of solid to vapour at constant temperature and pressure

D. convert a unit mass of liquid to vapour at a temperature of 100°C and a pressure of one atmosphere.

5. A sample of aluminum metal absorbs 9.86 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. 72

B. 1.5

C. 65

D. 8.1

6. The specific latent heat of fusion of a substance is defined as the amount of thermal energy required to change the phase of

A. the substance at constant temperature

B. unit mass of the substance to liquid at constant temperature.

C. unit mass of the substance at constant temperature.

D. the substance to gas at constant temperature.

7. The specific heat capacity of a metal block of mass m is determined by placing a heating coil in its centre, as shown in the diagram above.

The block is heated for time t and the maximum temperature change recorded is Äè. The ammeter and voltmeter readings during the heating are I and V respectively.Which one of the following is not a source of error in the experiment?

A. Some thermal energy is retained in the heater.

B. The thermometer records the temperature at one point in the block.

C. Some thermal energy is lost from the variable resistor in the circuit.

D. The block is heated at its centre, rather than throughout its whole volume.

8. The pressure of a fixed mass of gas in a cylinder is measured. The volume of the gas in the cylinder is then slowly decreased. The temperature of the gas does not change. Which graph could show the change of pressure of the gas during this process?

9. Some air is trapped inside a small balloon. The average kinetic energy of the air molecules in the balloon is increased.What remains the same?

A the density of the air in the balloon

B the mass of the air in the balloon

C the temperature of the air in the balloon

D the volume of the air in the balloon

10. An airtight container holds a fixed quantity of gas. Its pressure and volume are measured on four occasions when the temperature is 20 °C.The results are shown in the table. Which set of readings is incorrect?

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