# If 450 mL of 6.0 M KBr solution is diluted to 900 mL, what is the concentration of the KBr solution?

Dec 18, 2015

The concentration of the diluted KBr solution is 3 M.

#### Explanation:

Use the dilution equation ${M}_{1} {V}_{1} = {M}_{2} {V}_{2}$, where $M$ is molarity in mol/L, and $V$ is volume in liters.

Given/Known
${M}_{1} = \text{6.0 M"="6.0 mol/L}$
${V}_{1} = 450 \cancel{\text{mL"xx(1"L")/(1000cancel"mL")="0.45 L}}$
${V}_{2} = 900 \cancel{\text{mL"xx(1"L")/(1000cancel"mL")="0.9 L}}$

Unknown
${M}_{2}$

Solution
Rearrange the dilution equation to isolate ${M}_{2}$ and solve.
${M}_{1} {V}_{1} = {M}_{2} {V}_{2}$

${M}_{2} = \frac{{M}_{1} {V}_{1}}{{V}_{2}}$

M_2=(6.0"mol"/"L"xx0.45cancel"L")/((0.9cancel"L"))="3 mol/L"="3 M"