1. Chapter 4: Heat Form 4 1 Physics Next > The study of matter

2. Objectives: ( what you will learn ) 1) understanding Heat as a form of Energy 2) understanding the Laws Physics: Chapter 4 2 < Back Next >

4. 4 Heat When 2 bodies are in thermal equilibrium , there is no net flow of heat between the two bodies. Specific heat capacity , c of a substance = amount of heat neede to raise temperature of 1 kg of the substance by 1 o C. It is measured in J kg -1 C -1 . < Back Next > Amount of heat of a body, Q = mc Ө where m = mass of object c = specific heat capacity Ө = change in temperature

5. 5 Specific latent heat of fusion is the heat needed to change 1 kg of a substance from solid state to liquid state without any change in temperature. It is also the amount of heat needed to change 1 kg of the substance from liquid state to vapour state without any change in temperature. Heat < Back Next > Latent heat absorbed or released during the change in states, Q = m l where m = mass of object l = specific latent heat

6. 6 Boyle’s Law The volume of a fixed mass of gas is inversely proportional to pressure provided temperature is constant. Charles’ Law The volume of a fixed mass of gas is directly proportional to its absolute temperature provided the pressure remains constant. The Laws P 1 V 1 = P 2 V 2 < Back Next > V 1 V 2 T 1 T 2 =

7. 7 Pressure Law The pressure of a fixed mass of gas is directly proportional to its absolute temperature provided the volume remains constant. General Gas Law Summarizes Boyle’s Law, Charles’ Law and Pressure Law. The Laws < Back Next > P 1 P 2 T 1 T 2 = P 1 V 1 P 2 V 2 T 1 T 2 =

8. 8 The temperature of –273 o C is the minimum temperature which can be achieved by the gas. This temperature is known as absolute zero . The Laws < Back Next > Relationship between Celcius and Kelvin . Ө o C = ( Ө + 273) K