Q. 2.63 - An Introduction to General, Organic, and Biological Chemistry

Question

Using conversion factors, solve each of the following clinical problems:

a. You have used $250 \mathrm{L}$ of distilled water for a dialysis patient. How many gallons of water is that? 

b. A patient needs $0.024 \mathrm{g}$ of a sulfa drug. There are $8-\mathrm{mg}$ tablets in stock. How many tablets should be given?

c. The daily dose of ampicillin for the treatment of an ear infection is $115 \mathrm{mg}/\mathrm{kg}$ of body weight. What is the daily dose for a $34-\mathrm{lb}$ child?

d. You need $4.0 \mathrm{oz}$ of a steroid ointment. How many grams of ointment does the pharmacist need to prepare?

Step-by-Step Solution

Answer

(a) The $66 \mathrm{gal}$ of water in there.

(b) The $3$ tablets are there in stock

(c) The $1800 \mathrm{mg}$ is the daily dose for child

(d) The $110 \mathrm{g}$ of ointment does the pharmacist need to prepare

Part (a) Step 1: Given information

We need to find out the gallons of water

Part (a) Step 2: Explanation

We know that 

The

Therefore, gallons in $250 \mathrm{L}$ are,

$\frac{0.26 \mathrm{gal}}{1 \cancel{\mathrm{L}}}\times 250 \cancel{\mathrm{L}}=66 \mathrm{gal}$

Part (b) Step 1: Given information

We need to find the no. of tablets that should be given 

Part (b) Step 2: Explanation

We know that

The $1 \mathrm{mg}=1000 \mathrm{g}$

Therefore, no. of tablets are,

$\frac{1000 \cancel{\mathrm{mg}}}{1 \cancel{\mathrm{g}}}\times \frac{0.240 \cancel{\mathrm{g}}}{8 \cancel{\mathrm{mg}}}=3 \mathrm{tablets}$

Part (c) Step 1: Given information

We need to find the daily dose for a child

Part (c) Step 2: Explanation

We know that

The $1 \mathrm{kg}=2.20 \mathrm{lb}$

And as given $115 \mathrm{mg}=1 \mathrm{kg}$

Therefore, a daily dose for a child is

$\frac{1 \cancel{\mathrm{kg}}}{2.20 \cancel{\mathrm{lb}}}\times \frac{115 \mathrm{mg}}{1 \cancel{\mathrm{kg}}}\times 34 \cancel{\cancel{\mathrm{lb}}}=1800 \mathrm{mg}$

Part (d) Step 1: Given information

We need to find out the grams of ointment does the pharmacist need to prepare

Part (d) Step 2: Explanation

We know that

The $1 \mathrm{g} =0.035 \mathrm{oz}$

Therefore, grams of ointment does the pharmacist need to prepare are,

$\frac{1 \mathrm{g}}{0.035 \cancel{\mathrm{oz}}}\times 4 \cancel{\mathrm{oz}}=110 \mathrm{g}$