Question

Ketamine, Sometimes used as an adjuvant to general Anesthesia, it’s available as a 10.0% (w/v) solution. Calculate the volume of the solution that contains 30. mg of ketamine. Be sure your answer has a unit symbol and is running to the CORRECT NUMBER OF SiGNIFICANT DIGITS.

Answer 1

1) List known values

Ketamine solution: 10.0% (w/v) solution

Mass of Ketamine: 30mg

2) List unknown values

The volume of solution.

3) Set the equation

$mass\text{ percent=}\frac{\text{grams of solute}}{\text{milliliters of solution}}\cdot100$

4) Convert mg to g.

$\text{gramsofsolute}=30mg\cdot\frac{1g}{1000mg}=0.03g\text{ of ketamine}$

5) Plug in known quantities and solve for volume.

$10.0=\frac{0.03g\text{ of ketamine}}{\text{volume of solution (mL)}}\cdot100$

Rearrange algebraically

$\text{Volume of solution (mL)=}\frac{0.03g\text{ of ketamine}}{10}\cdot100=\text{ 0.}3mL$

The volume that contains 30 mg of ketamine is 0.3mL

.