Question

How many grams are there in 9.4 X 1025 molecules of hydrogen gas, H2?
How do I solve this I need step ppl!
@Frostbite anychance u can help me?

Answer 1

You wanna give it a try or totally clueless?

Answer 2

totally clueless

Answer 3

I don't even remember learning this :(

Answer 4

All we are going to use is good old
\[\Large m=M \times n\]And I'm going to introduce you to a new equation:
\[\Large N=N_{A} \times n\]
Where \(N\) is the amount of molecules and \(N_{A}\) is the Avogadro constant.
Think you can do it now? :)

Answer 5

moles=mass *n? whats n?
Avogadros number is 6.02*10^23 I believe

Answer 6

"moles=mass *n" not sure I follow. n is the amount of moles.

Answer 7

ooooo so
moles=mass*(6.02*10^23)

Answer 8

i am confused

Answer 9

Not mass.
Amount of particles = amount of moles * Avogadro's constant. :)

Answer 10

eh still not really clear

Answer 11

amount of particles? I thought I needed grams

Answer 12

I know, but we need to find \(n\) the amount of substance in mol first, and we do so by using the equation I wrote.

Answer 13

ooo
wait
so would it be
amount of particles=9.4*10^25

Answer 14

Exactly! :)

Answer 15

so how do I get grams from amount of particles?

Answer 16

uh can u show me this one, im lagging a bit

Answer 17

Sure :)
We start by finding the amount of substance:
\[\Large N=n \times N _{A} \to n=\frac{ N }{ N _{A} }\]
Now that we know the amount of substance we put in into the equation:
\[\Large n=\frac{ m }{ M } \to m=n \times M=\frac{ N }{ N _{A} }\times M\]
So:
\[\Large m=\frac{ 9.4 \times 10^{25} }{ 6.02214×10^{23} ~ \frac{ 1 }{ mol } } \times 2.01588 \frac{ g }{ mol }\]

Answer 18

312?

Answer 19

I haven't calculated it, but it should be correct what I have written.

Answer 20

I know but I had to round it :)

Answer 21

so im guessing it's probably right, right?

Answer 22

312 is what you got when you typed in what I had written and round it?

Answer 23

I get 314.68 g

Answer 24

156 * 2=312

Answer 25

o what about sig digits?

Answer 26

lol they only give us two. So if we should be good students we should only use two as well and say:
\[\large m=3.1 \times 10^{2} ~ \sf g\]

Answer 27

But does my calculations makes sense to you?

Answer 28

yes very much,
but I have trouble remembering the steps sometimes

Answer 29

ty so much!!!!!!!!!

Answer 30

You are more than welcome anytime.