How many grams of a drug substance should be added to 240 mL of water to make a 4% (w/w) solution.
To determine the number of grams of a drug substance needed to make a 4% (w/w) solution, you need to know the weight of the drug substance in the solution.
4% (w/w) means that 4 grams of the drug substance is present in 100 grams of the solution.
Let x be the weight of the drug substance in grams required to make the solution.
For a 4% (w/w) solution, you can set up the following equation:
x grams / 100 grams = 4 grams / 100 grams
Cross-multiplying, we get:
100 * x grams = 4 * 100 grams
100x = 400
Dividing both sides by 100, we get:
x = 4 grams
Therefore, 4 grams of the drug substance should be added to 240 mL of water to make a 4% (w/w) solution.