If Z is a compressibility factor, van der Waals equation at low pressure can be written as:

The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is 1 : 4. The ratio of number of their molecule is:

For complete combustion of ethanol, C₂H₅OH(l) + 3O₂(g) $$\to$$ 2CO₂(g) + 3H₂O(l) the amount of heat produced as measured in bomb calorimeter, is 1364.47 kJ mol^–1 at 25^oC. Assuming ideality the Enthalpy of combustion, $$\Delta _CH$$, for the reaction will be : (R = 8.314 kJ mol^–1)

For the reaction SO₂ (g) + $${1 \over 2} O_2(g) \leftrightharpoons$$ SO₃(g).
if K_P = K_C(RT)^x where the symbols have usual meaning then the value of x is: (assuming ideality)