Question

How many atoms are in 2.54 moles of NaCl?

Look in comments.

Answer 1

This is how far I got:

2.54mol x 6.02 x 10^23 over 1 mol. The mols cancel out and I got 1.53 x 10^24 atoms of NaCl.

But I got that wrong and there's another step but idk what that one is. What do I do next?

Answer 2

You're on the right track, but thus far you've only found the number of NaCl units.

Now you need to multiply by the number of atoms in each NaCl unit, how many atoms are there in each NaCl?

Answer 3

Idk how to figure that out tho.

Answer 4

NaCl is made from Na and Cl

so in each unit, there are 2 atoms

Answer 5

2 atoms because there's one Na and one Cl, correct?

Answer 6

yesyes

Answer 7

Ok so what do I do next them?

Answer 8

Then*

Answer 9

so earlier (by multiplying the moles times Avogadro's number) you found the number of NaCl units (they can't be called molecules because they're ionic compounds).

Now to find the number of atoms you multiply the number of units by the number of atoms in a single unit.

So multiply by 2

Answer 10

Ohhhhhhhhhh ok! So my answer would be 3.06 x 10^24

Answer 11

yep!

Answer 12

Thank you so much.

Answer 13

No problem!

Answer 14

@aaronq do you think you'd be able to help me with another question?

Answer 15

sure, post it

Answer 16

How many liters are in 8.67 moles of Cl2 at STP?

I know I have to set it up just like when I do other conversions but what is the STP number? I don't remember.

Answer 17

Typically you would use the ideal gas law, \(\sf PV=nRT\), but since this is at STP, you can use the fact that 1 mole of any gas occupies 22.414 L

Answer 18

Ok, yeah that number looks familiar. So, one mol of STP=22.4 L STP.

Thank you :) I might have one more question after but I won't know that until I do this one lol. But thanks :)

Answer 19

No problem!

My notifications havent been working well, so I might take a while to see it

Answer 20

Ok so here's what I did,

8.67 mol Cl2 x 22.4 L STP over 1 mol Cl2. The mols cancel out and I got 194.20 L.

Did I do it right?

Answer 21

@aaronq

Answer 22

yep thats right