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Showing posts with the label CALORIMETRY

What is SMOG?

Literally,  smoke + fog= smog. Smoke is the collection of unburnt fuel particles suspended in the air. Fog is the suspended water particles in the air. The combination of these suspended particles gives the smog.

Temperature doesn't change during phase change( melting, boiling etc..). Why?

The heat added to the solid is absorbed by the particles and it is utilised in overcoming the intermolecular force of attraction between the particles. So heat absorbed in solids is changed to potential energy without any change in kinetic energy of the molecules. As temperature in Kelvin scale is the measure of kinetic energy of particles, there is no change in temperature during melting.

CALORIMETER

It is a device to measure the heat lost or gained by one substance mixed with another at different temperature. It is based on the principle of mixtures or principle of calorimetry. Calorimeter is made of thin sheet of copper kept in a wooden jacket to with other insulating materials so that the process exchange heat by conduction is checked. Its surfaces are polished to check the process of radiation. Wooden or asbestos lid is used to minimise the loss of heat by convection. Thin sheet is used to lower the heat capacity.