can someone explain how to do these 2 chemistry problems?

Question

can someone please explain how to do these step by step?

1) hydrogen fuels are rated with respect to their hydrogen content. determine the percent hydrogen for the following fuels:
a) ethane, C2H6
b) methane, CH4
c) whale oil, C32H64O2

can someone please tell me how to do these? even just doing 1 or 2 of these would maybe teach me how to do it.

2) oxidizers are generally compounds that contain relatively large mass percentages of oxygen. hydrogen peroxide and sodium nitrate are good oxidizing agents. compare the mass percent of oxygen in each of these compounds

i also need help with this one.

thank you very much?

Answer 1

1..a...Ethane..C2H6 Mol.mass = 30.....H6 = 6
6 ÷ 30 = 0.20 = 20% Hydrogen (0.20 x 100).

b...Methane..CH4 Mol.mass = 16...H4 = 4
4 ÷ 16 = 0.25 = 25% Hydrogen (0.25 x 100)

c...Whale oil..C32H64O2..Mol.mass = 12x32 + 1x64 + 16x2
= 384 + 64 + 32 = 480..H=64.. = 64 ÷ 480 = 0.1333
= 13.33% Hydrogen (0.1333 x 100).

2..a..Hydrogen peroxide ..H2O2 Mol.mass = (1 x 2) + (16 x 2)
= 34...
= O = 32... 32 ÷ 34 = 0.9411
= 94.11% Oxygen (0.059 x 100)

b...Sodium nitrate..NaNO3..Mol.mass = 23 + 14 + (16x3)
= 85...O = 48..
= 48 ÷ 85 = 0.565 = 56.5% Oxygen (0.565 x 100)

Answer 2

The Mr of C2H6 is 30, of which H is 6.
So the percentage of H = 6/30 x 100.

The Mr of H2O2 is 34, of which O is 32.

So the percentage of O = 32/34 x 100.

Now you can do the others.

Answer 3

% by mass

mass hydrogen/mass ethane * 100

6/18 * 100 = 33%

b) 4/(12+4) * 100 = 25%

c) now try c), the answer you are looking for 13.3%