Question

There are four hydrogen atoms in a molecule of methane (CH4). How many hydrogen atoms are there in two moles of methane?
I know that the answer is 4.82 * 10^24 but I'm not completely sure how to get there

Answer 1

so in two moles of methane (\(CH_4\)) there are 8 moles of hydrogen atoms, correct?


Use: \(\sf moles=\dfrac{atoms}{N_A}\)

where \(N_A\) is avogadro's number

Answer 2

? mols=8/6.02x10^23=4.82x10^24

Answer 3

you dont know the amount of atoms though, that's the unknown.

8 \( \sf \large moles\) of hydrogen atoms

Answer 4

It says there are 4 atoms in a molecule

Answer 5

yeah, in 1 molecule.

later it says "in two moles of methane, how many hydrogen atoms?"

Answer 6

So the problem is 2 moles=? atoms/6.02x10^23

Answer 7

no. it's asking for the number of hydrogen atoms, not the number of molecules of methane.

Think about this. you have two moles of methane \(CH_4\), but each molecule has 4 atoms of H.

So there are 2 moles*4=8 moles of H atoms

Answer 8

Each molecule of methane has 4 hydrogen atoms not each mole has 4 atoms

Answer 9

lol did i say "each mole has 4 atoms"?

Answer 10

I think so.

Answer 11

I've really confused myself now. Obviously it isn't a good idea to go back and forth between stoichiometry and college applications

Answer 12

I didn't say that.

And no, you should probably focus on 1 thing at a time, specially if the concepts arent solid.

I think your confusion is with what a mole is.

A mole is just a number, like say a dozen - it's just a really large number.

1 dozen of eggs = 12 eggs
1 mole of eggs = 6.022*10^23 eggs

1 dozen methane molecules = 12 methane molecules

each molecule has 4 atoms of hydrogen

1 dozen methane molecules have 4 dozens of hydrogen atoms

it's the same with moles.

2 moles of methane have 8 moles of hydrogen (atoms)

Answer 13

Okay. How does it get to 4.82*10^24?
It gave us the correct answers but we have to come up with the calculations

Answer 14

right. so we have established that there are 4 moles of H, right?

now it's a plug and chug

\(\sf 8~moles~of~H=\dfrac{\#~atoms}{N_A}\rightarrow \#~atoms=8~moles*N_A=4.8176*10^{24}\)

Answer 15

i meant 4 moles per 1 mole of methane (thus 8 moles of H in total)

Answer 16

Wouldn't the number of atoms be 8?

Answer 17

why would it be?

Answer 18

Because there are 4 atoms in each molecule and doesn't one molecule= one mole which mean that there are 8 atoms in two moles

Answer 19

nope.

1 molecule is one molecule

1 mole of molecules = 6.022*10^23 molecules

Answer 20

Okay