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Quantity of heat Q = mcθ absorbed or lost by a substance 4. What does specific heat 900 J of heat needs to be supplied to 1 kg of aluminium 900 J kgof aluminium to produce a 1 °C -1 1 °C mean? temperature increase. 5. What does specific heat 4 200 J of heat needs to be supplied to 1 of water 4 200 J kg-1°C-1 kg of water to produce a 1 °C temperature mean? increase. 6. The physical When two objects of equal mass are heated at meaning of equal rates, the object with the smaller specific specific heat heat capacity will have a faster temperature. capacity, c When two objects of equal mass are left to cool down, the temperature of the object with smaller heat capacity will drop faster. 7. A substance with a small value of specific heat capacity 1. heats up and cools at a faster rate. For example, metal like iron, steel, copper and aluminium is used as pots and pans because they can be quickly heated up when there is only small heat absorption. 2. sensitive to temperature changes A thermometer has low specific heat capacities so it enables heat to be easily absorbed and released even when small quantities of heat are
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Experiment to determine the specific latent heat of vaporization for water. Electric power supply = 2 kW. Time taken = 5 minutes. Initial reading of the electronic balance = 685 g Final reading of the electronic balance = 565 g Mass of water vaporized, m = ………… Energy supplied by the heater, Q = Pt = ……….. Specific latent heat of vaporization: 11. Applications of Specific Latent Heat • Drinks can be cooled by adding in several cubes of ice. When ice melts a large amount of heat is absorbed and this lowers the temperature of the drink. • The freshness of fish and meat can be maintained by placing them in contact with ice. With its larger latent heat, ice is able to absorb a large quantity of heat from the fish as it melts. Thus, food can be kept at a low temperature for an extended period of time. • Water has a large specific latent heat of vaporization. This property enables steam to be used for cooking by the method of steaming. When steam condenses on the food, the latent heat is released directly onto the food enables the food to be cooked at a faster rate. • Our bodies feel cool after sweating. This is because latent heat of vaporization is absorbed from the body when sweat evaporates. As a result, the body is cooled by the removal of
Experiment to determine the specific latent heat of vaporization for water. Electric power supply = 2 kW. Time taken = 5 minutes. Initial reading of the electronic balance = 685 g Final reading of the electronic balance = 565 g Mass of water vaporized, m = ………… Energy supplied by the heater, Q = Pt = ……….. Specific latent heat of vaporization: 11. Applications of Specific Latent Heat • Drinks can be cooled by adding in several cubes of ice. When ice melts a large amount of heat is absorbed and this lowers the temperature of the drink. • The freshness of fish and meat can be maintained by placing them in contact with ice. With its larger latent heat, ice is able to absorb a large quantity of heat from the fish as it melts. Thus, food can be kept at a low temperature for an extended period of time. • Water has a large specific latent heat of vaporization. This property enables steam to be used for cooking by the method of steaming. When steam condenses on the food, the latent heat is released directly onto the food enables the food to be cooked at a faster rate. • Our bodies feel cool after sweating. This is because latent heat of vaporization is absorbed from the body when sweat evaporates. As a result, the body is cooled by the removal of