Molecule and ideal gas law

1. A cylinder contains a mixture of hydrogen and chlorine molecules. Compare without doing any calculations:

a) the relative mass of the molecules
b) the temperature of each gas
c) the average kinetic energy of the molecules
d) the average speed of the molecules

2. Find the number of atoms in
a) 52.5g of calcium metal
b) 1.5 mol of carbon
c) 1.5 mol of carbon dioxide

3. Find the volume of a gas at -30oC and 0.75 atm if it occupies a volume of 255L at 40.0oC and 1.25 atm.