# How many grams of NaOH are needed to prepare 800 mL Of 0.8 M solution (Mw NaOH = 40.00 g / mole) ?

##### 1 Answer

Aug 18, 2016

25.6 g

#### Explanation:

The molecular weight of NaOH is given as 40.00 g / mole. Hence, 1 mole would weigh 40.00 g.

A 0.8 M solution contains 0.8 moles per liter (molarity is moles per liter). Hence, in 1 liter there would be 0.8 x 40.0 g of NaOH, which is 32 g.

However, we have 800 ml, not 1 liter, and 800 ml is 0.8 liters.

So, we would have 32 x 0.8 g, which is: 25.6 g