To calculate amount of the heat received or given by substance it is necessary to find its weight and also temperature change. According to the table of specific thermal capacities to find this size for this material, and then to calculate amount of heat by a formula. It is possible to define amount of heat which is marked out at fuel combustion, having learned its lot and specific heat of combustion. Same situation with melting and evaporation.
It is required to you
- For determination of amount of heat take a calorimeter, the thermometer, scales, tables of thermal properties of substances.
Instruction
1. Calculation of amount of heat given or received by a body. Measure body weight on scales in kilograms, then take temperature and heat it, having as much as possible limited contact in the external environment, having again taken temperature. For this purpose use the heat-insulated vessel (calorimeter). Almost it can be done so: take any body at the room temperature, it also will be its initial value. Then fill in hot water in a calorimeter and ship a body there. After a while (not at once, the body has to heat up), take water temperature, it will be equal to body temperature. Find this size for material of which the studied body is made in the table of specific heat. Then the amount of heat which it received will be equal to the work of specific heat on the body weight and change of its temperature (Q=c • m • (t2-t1)). The result will be received in joules. Temperature can be taken in degrees Celsius. If amount of heat turned out positive – the body heats up if negative – it is cooled.
2. Calculation of amount of heat at fuel combustion. Measure the fuel weight which burns down. If fuel liquid, measure its volume and increase by density taken in the special table. Then find the specific heat of combustion of this fuel in the help table and increase by its weight. The amount of heat allocated at fuel combustion will be result.
3. Calculation of amount of heat during the melting and steam formation. Measure the mass of the melting body, and specific heat of melting for this substance from the special table. You will multiply these values and receive the amount of heat absorbed by a body when melting. The same amount of heat is allocated with a body at crystallization. To measure the amount of heat absorbed at liquid evaporation find its lot and also specific heat of steam formation. The work of these sizes will give the amount of heat absorbed by this liquid at evaporation. At condensation just the same amount of heat which was absorbed at evaporation will be allocated.