Question

What is the mass of three moles of ethane (c2h6)?

Answer 1

1 mole of C atoms weighs 12.01 g and 1 mol of H atoms weighs 1.0079 g. So, we know the molar mass of ethane also. Or, 30.07 g in 1 mole C2H6. So, we say the molar mass of ethane is 30.07 g/mol

Answer 2

mass =mol x relative molecular mass3mol x 30 =90g