How many moles of hydrogen are there in #25.3# #g# of methane, #CH_4#?

3 Answers
Dec 17, 2017

The answer is that there are #6.32# mol of hydrogen in #25.3# #g# of #CH_4#.

Explanation:

First step is to find the molar mass of methane:

Carbon is 12, hydrogen is 1, so #CH_4# is #12+4xx1=16#

Find the number of moles of #CH_4# in #25.3# #g#:

#n=m/M=25.3/16=1.58# mole

In each mole of #CH_4# there are 4 moles of hydrogen, so our answer is #4xx1.58=6.32# mol

Dec 17, 2017

There are 6.31 moles of hydrogen in 25.3 g of methane

Explanation:

Dividing 25.3 g of methane by its molar mass of 16.04 g gives you how many moles of methane are in 25.3 g of methane, and multiplying that number by the number of hydrogens (in this case, 4) gives you about 6.309 moles of hydrogen in 25.3 g of methane.

Dec 17, 2017

#3.16 " moles " H_2#

Explanation:

First, clarify whether you mean moles of #H_2# (the molecule) or moles of #H# (the atom). The second will be twice as much as the first.

For this example I will calculate the moles of the molecule, #H_2# as if it were the product of a reaction. Every mole of methane contains 2 moles of #H_2# (#4H#). So we just need to calculate the moles of methane from the mass and multiply by two.

#25.3g xx (1"mole")/(16g CH_4) = 1.581 " moles " CH_4#

#1.581 xx 2 = 3.16 " moles " H_2#