# Question #c5a04

Feb 24, 2017

A (1.0M)

#### Explanation:

In order to know the molarity of the solution we need to know the number of moles of CH3OH and the volume of water it is dissolved in.

The question tells us that the number of moles of CH3OH is $0.10 m o l$.

It also tells us that the mass ($m$) of water it is dissolved in is $100.0 g$.
The density ($\rho$) of water is $1.0 g . c {m}^{-} 3$.

$\rho = \frac{m}{V}$ so $V = \frac{m}{\rho}$

Therefore $V = \frac{100.0}{1.0} = 100.0 c {m}^{3}$

Before we can calculate the molarity we have to convert the volume of water into ${\mathrm{dm}}^{3}$ because $1 M = 1 m o l . {\mathrm{dm}}^{-} 3$:

$100.0 c {m}^{3} = 0.1000 {\mathrm{dm}}^{3}$

Molarity is moles per unit volume, so $M o l a r i t y = \frac{0.10 m o l}{0.1000 {\mathrm{dm}}^{3}} = 1.0 M$