Question

What is the mass of 3.8 × 10^24 atoms of argon (Ar)?
0.0039 g
0.16 g
6.3 g
250 g

I came up with 6.3 but now I'm starting to doubt myself after looking at the lesson again.

Answer 1

@JFraser

Answer 2

is \(3.8*10^{24}\) atoms larger or smaller than the quantity of one mole?

Answer 3

larger

Answer 4

so should \(3.8*10^{24}\) atoms of argon weigh less than the mass of one mole of argon?

Answer 5

no but how do you know how much one mole of argon is?

Answer 6

i do, because i have a periodic table

Answer 7

39.948?

Answer 8

so if 1 mole of argon should weigh 40g (give or take), and you have more than 1 mole of argon atoms, what's the only option that makes sense?

Answer 9

divide 3.8*10^24/40

Answer 10

no

Answer 11

divide\[3.8*10^{24}atoms * \frac{1mol}{6.022*10^{23}\space atoms}\]

Answer 12

will get you how many MOLES that is

Answer 13

the 1 mol is 40 right?

Answer 14

1 mole of argon weighs 40g, but that's only for argon do the number of moles first

Answer 15

\[3.8*10^{24}/6.022*10^{23}\]

Answer 16

that will tell you how many moles there are, then you need to turn that into grams (using the molar mass)

Answer 17

so it would be 6.3 moles?

Answer 18

yes

Answer 19

\[6.3*40/6.022*10^{23}\]

Answer 20

no

Answer 21

just \[6.3 moles * \frac{40g}{1 \space mole}\]

Answer 22

what is the one mole then? or does it just stay as 1 mole?

Answer 23

the moles cancel from the moles on top, leaving only grams

Answer 24

i got 250

Answer 25

you should

Answer 26

thank you so much!

Answer 27

YW