Classify the following into physical changes and chemical changes.
1. Melting of ice 2. Heating magnesium in water 3. Silver bromide kept exposed to sunlight 4. Change happening to soda water on opening its bottle.

Melting of' ice is a physical change while burning of magnesium is a chemical change. Why?

a) Classify the following into intensive and extensive properties. i) Inernal energy ii) Density iii) Heat Capacity iv) Temperature b) Calculate the standard free energy change ( DeltaG^theta ) for the conversion of oxygen to ozone frac{3}{2}O_(3(g))rightarrowO_(3(g) at 298 K if the equilibrium constant for the conversion is 2.47xx10^(-29). (Given R = 8.314 JK^-1 mol^-1 )

When water is heated at its boiling point or melting point, its temperature does not change. What are the boiling and freezing points of water?

Sulphur has allotropic forms . Which of the following is not true? (1)Rhombic sulphur changes to monoclinic at 369 K and at this temperature both form exist. (2)Both alpha and beta forms containS8 molecules having crown structure heating to 600°C, becomes diamagnetic (3)Sulphur also exist as S6 chair form with S-S bond length 205.7 pm and angle 102.2

When water is heated at its boiling point or melting point, its temperature does not change. Why is there no change in temperature?

When water is heated at its boiling point or melting point, its temperature does not change. What is meant by boiling point and melting point?