2.2.2. Specific heat capacity
A subsection of Physics, 5054, through 2. Thermal physics
Listing 10 of 60 questions
Liquid air contains a mixture of oxygen and nitrogen. The boiling point of nitrogen is –196 °C and the boiling point of oxygen is –183 °C. A sample of liquid air in a beaker is allowed to warm up slowly. shows how the reading of a thermometer in the beaker varies with time t. -200 temperature / C t / min -190 -180 Describe the two changes of state that occur and state when they occur. The liquid air contains 200 g of liquid oxygen and 800 g of liquid nitrogen. The specific heat capacity of liquid oxygen is 1.7 J / (g °C) and the specific heat capacity of liquid nitrogen is 2.0 J / (g °C). Calculate the thermal energy needed to warm the liquid from –205 °C to −196 °C. State the formula that you use in your calculation. energy =
5054_s08_qp_2
THEORY
2008
Paper 2, Variant 0
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shows a laboratory thermometer. °C –10 State the range of the thermometer. State one change in the design of the thermometer to increase its range. Describe how the behaviour of a more sensitive thermometer is different from a less sensitive thermometer. State one change in the design of the thermometer to make it more sensitive. Describe how a clinical thermometer differs from a laboratory thermometer. A diagram may be included in your answer. In the space below, draw a labelled diagram of a thermocouple thermometer. State two reasons why a thermocouple thermometer is sometimes a better choice than a laboratory thermometer. shows a copper block of mass 1.8 kg with two holes in the top. An 80 W heater is placed in one hole and a thermometer in the other. heater copper block thermometer The heater is switched on for 5.0 minutes. Assume that no energy is lost from the block. Calculate the energy supplied to the block. energy supplied = The specific heat capacity of copper is 390 J / (kg °C). Calculate the rise in temperature of the block. temperature rise =
5054_s10_qp_21
THEORY
2010
Paper 2, Variant 1
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In an experiment to measure the specific heat capacity of water, an electric heater heats water in a glass beaker. The temperature of the water is measured at regular intervals of time. shows how the temperature varies with time t. temperature / °C t / s Use to determine the change in temperature between t = 0 and t = 100 s, change = t = 100 s and t = 200 s. change = State and explain why the values in are different. Describe and explain what happens to the water if the heating is continued. The experiment in is repeated using 72 g of water. The heater supplies 7400 J of thermal energy to the water and the temperature rise of the water is 23 °C. Calculate the specific heat capacity of water. specific heat capacity = A bullet of mass 72 g is fired from a gun at a speed of 450 m / s. Calculate the kinetic energy of the bullet. energy = The amount of internal energy gained by the water and the amount of kinetic energy gained by the bullet are approximately equal. Describe the change in the motion of the molecules of the water and of the molecules of the bullet that this addition of energy has caused. water: bullet: A thermocouple is used in the experiment in . In the space below, draw a labelled diagram of a thermocouple thermometer. Show clearly the part of the thermocouple that is placed in the water in this experiment.
5054_s11_qp_22
THEORY
2011
Paper 2, Variant 2
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Questions Discovered
60