# How many grams of potassium carbonate are needed to make 200 mL of a 2.5 M solution?

Mar 12, 2016

We need approx. $70$ $g$ of potassium carbonate.

#### Explanation:

$\text{Concentration}$ $=$ $\text{Moles of solute"/"Volume of solution (L)}$

Thus, $\text{Moles of solute}$ $=$

$\text{Concentration "xx" Volume of solution}$

$2.50 \cdot m o l \cdot {L}^{-} 1 \times 0.200 \cdot L$ $=$ $0.500 \cdot m o l$

$0.500 \cdot \cancel{m o l} \times 138.21 \cdot g \cdot \cancel{m o {l}^{-} 1} \text{ potassium carbonate}$ $=$ ??g" potassium carbonate"