Question

a 750.-ml bottle of vodka contains $2.8 \times 10^{2}$ ml of ethanol. what is the $\frac{volume}{volume}$ percent concentration of ethanol? be sure your answer has the correct number of significant figures. $square$ % $(\frac{v}{v})$ ethanol

Explanation:

Step1: Define v/v% formula

$\text{volume/volume \%} = \frac{\text{volume of solute}}{\text{volume of solution}} \times 100\%$

Step2: Substitute given values

$\text{volume/volume \%} = \frac{2.8 \times 10^2\ \text{mL}}{750.\ \text{mL}} \times 100\%$

Step3: Calculate and round result

$\text{volume/volume \%} = 0.3733... \times 100\% = 37\%$

Answer:

37% (v/v) ethanol