Question

A student has a sample of isopropanol (C3H,OH) 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?
0.765
1.31
78.6
4.720

Answer 1

I think it goes like this.

mass = 78.6 g
molar mass = 60.1 g/mol
amount (in mols) = mass/mol
78.6 g / 60.1 g/mol = 1.30782 mol

^^rounded to 3 sig figs, final answer = 1.31mol

Answer 2

Answer:

$\boxed{\text{ 1.308 mol}}$

Explanation:

$\text{Moles} = \text{78.6 g } \times \dfrac{\text{1 mol}}{\text{60.1 g}} = \text{1.308 mol}\\\\\text{ The sample contains \boxed{\textbf{ 1.308 mol}} of isopropyl alcohol}$