Heat

Example 1:A fish releases a bubble of air of volume 1cm³ at the bottom of a lake. The depth of the lake is 10m. Find the volume of the bubble when it reaches the surface of the pond. (Assume that the atmospheric pressure is equal to 10m of water) Answer:V1 = 1cm³P1 = 20m waterV2 = … Read more

Charles’ Law Charles’ law states that for a fixed mass of gas, the volume of the gas is directly proportional to the absolute temperature of the gas provided the pressure of the gas is kept constant. Formula: Explanation When temperature increases, the average kinetic energy of the gas particles will increase. The air molecule move … Read more

Pressure Law Pressure law states that for a fixed mass of gas, the pressure of the gas is directly proportional to the absolute temperature of the gas provided the volume of the gas is kept constant. Formula: Explanation The kinetic energy of gas molecules increases with temperature. The air molecules collide with the wall of … Read more

Boyle’s law Boyle’s law states that the pressure of a gas with constant mass is inversely proportional to its volume provided the temperature of the gas is kept constant.Formula: Explanation  When the volume of gas decreases, the number of gas particles per unit volume increases. As a result, the frequency of collision between the air … Read more

The kinetic theory of gases explains the relationship between the pressure, temperature and volume of gases base on the following assumptions: The gas consists of very small particles, each of which has a mass. These particles are in constant, random motion. The rapidly moving particles constantly collide with each other and with the walls of … Read more

Rate of Evaporation Evaporation is the process of converting a substance (such as water) from its liquid state to its gaseous state at temperature lower than the boiling point of the liquid. There are several ways of making a liquid evaporate faster: Increase its temperature  Increase its surface area  Pass air through it or across … Read more

Measuring the Specific Latent Heat of Vaporization of Water Figure above shows the apparatus used. When the water in the can is boiling vigorously, the mass reading on the balance is noted and a stopwatch started. A few minutes later, the stopwatch is stopped and the mass reading is taken again. The difference in the … Read more

Measuring the Specific Latent Heat of Fusing of Ice Figure above shows the apparatus setup to determine the specific latent heat of fusion of ice. Some ice at 0 °C is heated by a small electric heater which is left switched on for several minutes.  Some of the ice melts to form water which runs … Read more

Specific Latent Heat The specific latent heat of a substance is the amount of heat requires to change the phase of 1 kg of substance at a constant temperature. Specific latent heat is measured in J/kg, if energy is measured in J and mass in kg.For example, specific latent heat of ice is 334000J/kg means … Read more