How many moles is 118 grams of Argon

Question

asked Aug 25, 2022 175k views

1 Answer

Boris Silantev · Answer 1 · 2022-08-29T20:20:52+0000

Answer:

$\boxed {\boxed {\sf About \ 2.96 \ moles \ of \ Argon}}$

Step-by-step explanation:

To convert from grams to moles we must use the molar mass, which is found on the Periodic Table.

Use the molar mass as a ratio.

$(39.9 \ g \ Ar)/(1 \ mol \ Ar)$

Multiply by the given number of grams: 118

$118 \ g \ Ar *(39.9 \ g \ Ar)/(1 \ mol \ Ar)$

Flip the fraction so the grams of argon will cancel each other out.

$118 \ g\ Ar * (1 \ mol \ Ar)/(39.9 \ g \ Ar)$

$118 * ( 1 \ mol \ Ar)/(39.9 \ g \ Ar)$

$\frac {118 \ mol \ Ar }{ 39.9 }$

$2.95739348 \ mol \ Ar$

The original measurement of grams had 3 significant figures, so our answer must have 3 sig figs.

For the number we calculated, that is the hundredth place. The 7 in the thousandth place tells us to round the 5 to a 6.

$2.96 \ mol \ Ar$

There are about 2.96 moles of Argon in 118 grams.