A certain mass of glucose (C6H12O6) contains 100 g of carbon. How much hydrogen does it contain?

16.7 g H

Explanation:

1 mol C6H12O12 contains 6 mol C atoms and 12 mol H atoms, that means 2 times more moles of H than C.

100 g C*1 mol C/12 g C=8.333 mol C

So, there are 8.333*2 = 16.67 mol H

16.67mol H*1g H/1mol H = 16.67≈16.7 g H