Question

how many moles of water H2O contain 2.0 x 10^22 molecules of water? express the quantity in moles to two significant figures

Answer 1

1 mol H₂O ----------- 6.02x10²³ molecules
? mol H₂O --------- 2.0x10²² molecules

Number of moles = Number of molecules / Avogadro's number

moles = 2.0x10²² * 1 / 6.02x10²³

= 2.0x10²² / 6.02x10²³

= 0.3322 moles

hope this helps!