Question

How many moles of water,

H
2
O
, contain
2.0×
10
22
molecules of water? (See the hints for assistance in interpreting scientific notation.)

Answer 1

1 mol of any substance=6.022 * 10²³ particles



Now, we calculate the number of moles of this sample:

1 mol----------------------------6.022 * 10²³ molecules
x-----------------------------------2.0 * 10²² molecules

x=(1 mol * 2.0 * 10²² molecules) / (6.022 *10 ²³ molecules)=0.033 moles=
=3.3 *10⁻² moles.

Answer: 3.3 * 10⁻² moles.