Question

amoxil is an antibiotic used to treat infections of the ear, nose, and throat. it is sold as a suspension in water.
your answer
part 1 of 2
what is the \\( \frac { \text { weight } } { \text { volume } } \\) percent composition in a suspension of amoxil that contains 45 \\( \frac { \mathrm { mg } } { \mathrm { ml } } \\) ? be sure your answer has the correct number of significant figures.
\\( \frac { \text { weight } } { \text { volume } } : \\) 4.5 %
part 2 of 2
if the typical pediatric dose is 31 \\( \frac { \mathrm { mg } } { \mathrm { kg } } \\) per day, what volume of drug is given for a 15. kg child? be sure your answer has the correct number of significant figures.
volume: 10 ml

Explanation:

Part 1 of 2: Calculate the weight/volume percent composition

Step1: Recall the formula for weight/volume percent

The formula for weight/volume percent (\(\text{w/v}\%\)) is \(\text{w/v}\%=\frac{\text{mass of solute (mg)}}{\text{volume of solution (mL)}}\times\frac{1}{10}\). Given the concentration is \(45\ \frac{mg}{mL}\).

$$ \text{w/v}\%=\frac{45\ mg}{1\ mL}\times\frac{1}{10}= 4.5\% $$

Part 2 of 2: Calculate the volume of the drug

Step1: Calculate the total mass of the drug needed

First, find the mass of the drug required for a \(15\ kg\) child. Using the dose \(31\ \frac{mg}{kg}\) per day.
The mass \(m\) of the drug is \(m = 31\ \frac{mg}{kg}\times15\ kg=465\ mg\)

Step2: Calculate the volume of the drug

Since the concentration is \(45\ \frac{mg}{mL}\), use the formula \(V=\frac{m}{C}\) (where \(V\) is volume, \(m\) is mass, and \(C\) is concentration)

$$ V=\frac{465\ mg}{45\ \frac{mg}{mL}}=\frac{465}{45}\ mL = 10.33\cdots\ mL\approx10\ mL\ (two - significant figures) $$

Answer:

Part 1 of 2: \(\frac{\text{weight}}{\text{volume}}:4.5\%\)
Part 2 of 2: Volume: \(10\ mL\)