Question

A student has a sample of isopropanol (C3H7OH) that has a mass of 78.6 g. The molar mass of isopropanol is 60.1 g/mol. How many moles of isopropanol are contained in this sample?

Answer 1

The thing we are asked to calculate here is the amount of the substance in the given sample in units of moles. To obtain this value, the molar mass of the substance is needed. Molar mass has the units of grams per mole so it is a useful value for converting mass into moles.

78.6 g ( 1mol / 60.1g) = 1.31 mol isopropanol

Answer 2

Answer : The number of moles of isopropanol are 1.308 moles.

Solution : Given,

Mass of isopropanol = 78.6 g

Molar mass of isopropanol = 60.1 g/mole

Formula used :

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

Now put all the given values in this formula, we get the number of moles of isopropanol.

`\text{ Number of moles}=(78.6g)/(60.1g/mole)=1.308moles`

Therefore, 1.308 moles of isopropanol are contained in this sample.