what is the relative mass of methane?

Question

how many moles of methane are there in 4g of pure methane?how many moles of oxygen are there in 7 dm3?

Answer 1

methane: CH4

Mr;
carbon 12
hydrogen 1

Mr of methane= 1*carbon+4*hydogen
=12+4
=16

therefore one mole of methane weighs 16 grams

4 g of methane= 4/16
=0.25 moles
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one mole of any gas occupies 24 dm3 at r.t.p

moles of oxygen in 7 dm3= 7/24
=0.292 moles