Question

What is the weight of oxygen in 10 mL of water? How many molecules of O₂ can we produce?

Answer 1

since density of water 1 so

10 ml of water we can consider as a 10 gr of water ( density = mass / volume formula)

moles of H2O = weight of H2O / molar mass of H2O = 10 g / 18 g/mol = 0.56 mol

lets look at the H2O

2H + 1O --> H2O

means one mole of H2O can have on emole of Oxygen

no of mole sof O = 0.56 mol

mass of oxygem = mol of O x molar mass of O = 0.56 mol x 16 g/mol = 8.89 gr

onemole of Oxygen can have avagadro no of molecules which is = 6.02 x 10²³ molecules

0.56 mol of O means 0.56/2 = 0.28 mole of O2

because O + O ---> O2

1 mole of O2 is having 6.02 x 10²³ molecules means

0.28 moles of O2 will have 0.28 x 6.02 x 10²³ molecules = 1.7 x 10²³ molecules