Question

calculate the volume of oxygen at 15 degree Celsius and 745mmHg pressure. which could be obtained by heating 10g of potassium trioxochlorate(v)

Answer 1

2KClO3 ==> 2KCl + 3O2
mols KClO3 = 10/molar mass KClO3 = ?
Use the coefficients in the balanced equation to convert mols KClO3 to mols O2. That's mols O2 at STP = ?mols KClO3 x 3 mols O2/2 mol KClO3 = ? mols KClO3 x 3/2 = ?
The use PV = nRT to convert mols O2 at STP to mols O2 at the conditions of the problem.