Question

What is the mass of a sample of water containing 3.55×1022 molecules of h2o?

Answer 1

6,02×10²³ -------------- 18g
3,55×10²² -------------- x
`x=(3,55*10^(22)*18g)/(6,02*10^(23))=10,61*10^(22-23)g=10,61*10^(-1)g=1,061g`

Answer 2

Answer: The mass of water sample is 1.062 g

Step-by-step explanation:

We are given:

Number of molecules of water =
`3.55* 10^(22)`

According to mole concept:

`6.022* 10^(23)` number of molecules are present in 1 mole of a compound

So,
`3.55* 10^(22)` number of molecules will be present in =
`(1)/(6.022* 10^(23))* 3.55* 10^(22)=0.059moles` of water.

To calculate the mass of a substance, we use the equation:

`\text{Number of moles}=\frac{Given mass}}{\text{Molar mass}}`

Molar mass of water = 18 g/mol

Moles of water = 0.059 moles

Putting values in above equation, we get:

`0.059mol=\frac{\text{Mass of water}}{18g/mol}\\\\\text{Mass of water}=1.062g`

Hence, the mass of water sample is 1.062 grams