# Snapquiz - Percentage Mass

This is the Snapquiz on Percentage Mass. Click here or use the embedded video if you haven't watched the lesson yet.

Question 1. A hydrogen atom has a relative atomic mass of 1 and an oxygen atom has a relative atomic mass of 16. What's the mass of all the oxygen atoms in an H2O molecule?

16.
2.
32.
1.

Question 2. A carbon atom has a relative atomic mass of 12 and a hydrogen atom has a relative atomic mass of 1. What's the percentage mass of all the carbon atoms in a CH4 molecule?

60%.
40%.
75%.
50%.

Question 3. What needs to be true about a chemical equation before we can calculate percentage mass?

It needs to be labelled.
It needs to be reversible.
It needs to be balanced.
It needs to be converted into a word equation.

Question 4. What is one twentieth as a percentage?

15%.
10%.
50%.
5%.

Question 5. Which number goes on the bottom of your fraction when you're calculating a percentage on a foundation level GCSE Science paper?

100%.
The small number.
The numerator.
The large number.