Question 9.10: Using Mass/Volume Percent to Calculate Mass of Solute A topi......
Using Mass/Volume Percent to Calculate Mass of Solute
A topical antibiotic is 1.0% (m/v) clindamycin. How many grams of clindamycin are in 60. mL of the 1.0% (m/v) clindamycin solution?
STEP 1 State the given and needed quantities.
STEP 2 Write a plan to calculate the mass.
STEP 3 Write equalities and conversion factors. The percent (m/v) indicates the grams of a solute in every 100. mL of a solution. The 1.0% (m/v) can be written as two conversion factors.
\begin{aligned} & 1.0\ g \text { of clindamycin }=100 .\text{ mL} \text { of solution } \\ & \frac{1.0\ g \text { clindamycin }}{100\text{ mL} \text { solution }} \text { and } \frac{100 .\text{ mL} \text { solution }}{1.0\ g \text { clindamycin }} \end{aligned}
STEP 4 Set up the problem to calculate the mass. The volume of the solution is converted to mass of solute using the conversion factor that cancels mL.
\begin{aligned} & \underset{\text{Two SFs}}{\mathrm { 60.\ \cancel{mL\ solution}}} \times \underset{\text{Exact}}{\overset{\text{Two SFs}}{\frac{1.0\ g \text { clindamycin }}{100 . \cancel{\text { mL-solution }}}}}=\underset{\text{Two SFs}}{0.60\ g \text { of clindamycin } } \end{aligned}
| ANALYZE THE
PROBLEM |
Given | Need | Connect |
| 60. mL of 1.0%(m/v)
clindamycin solution |
grams of
clindamycin |
% (m/v) factor |