How many grams of hydrogen are there in 16 grams of methane gas?

Answer 1

First you need atomic masses. Then you need to add them up to find the molecular mass of methane (CH4).

Carbon = 12.0 grams

Hydrogen = 1.0×4 = 4.0 grams

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Methane = 16.0 grams

Now that you know the total mass, you can figure out how much of the compound is actually hydrogen (by percent). So you take the mass of hydrogen and divide it by the total mass of methane.

4.0 ÷ 16.0 = .25 = 25% of methane is hydrogen

Now we take the 16 grams and figure out how much of that 16 grams is hydrogen. We know that 25% of it is hydrogen, so take one-fourth of 16 to get 4. But sometimes the numbers aren't as easy and you have to multiply them out.

25% of 16 = .25 × 16 = 4 grams hydrogen