Calculate the mass of solvent that would contain 3.0 mg of a drug if the concentration was 3.5%
3.5% what? w/w, w/v, v/v. I assume w/w from the wording of the problem.
3.5% w/w means 3.5g/100 g soln which is 3500 mg/100 g soln. You want 3.0 mg so you want
100 x 3.5/3500 = ? g soln.
To calculate the mass of the solvent, we can use the formula:
Mass of solvent = (Mass of drug) / (Concentration of drug)
Given:
Mass of drug = 3.0 mg
Concentration of drug = 3.5%
First, we need to convert the percentage to a decimal by dividing it by 100:
Concentration of drug = 3.5% / 100 = 0.035
Now we can substitute the values into the formula:
Mass of solvent = (3.0 mg) / (0.035)
Simplifying the equation, we get:
Mass of solvent = 85.71 mg
Therefore, the mass of the solvent that would contain 3.0 mg of the drug with a concentration of 3.5% is approximately 85.71 mg.
To calculate the mass of the solvent, we need to first determine the mass of the drug and then use the concentration to find the mass of the solvent.
Given:
Mass of the drug = 3.0 mg
Concentration = 3.5%
Step 1: Calculate the mass of the drug in grams.
Since the concentration is given as a percentage, we need to convert it to a decimal. Dividing it by 100 will give us the decimal form.
Concentration (decimal form) = 3.5% / 100 = 0.035
To find the mass of the drug in grams, we divide the given mass in milligrams by 1000.
Mass of the drug (in grams) = 3.0 mg / 1000 = 0.003 g
Step 2: Use the concentration to find the mass of the solvent.
The concentration is defined as the ratio of the mass of the drug to the mass of the entire solution (drug + solvent). We can rearrange this formula to solve for the mass of the solvent:
Concentration = Mass of drug / Mass of drug + Mass of solvent
Rearranging the equation, we can solve for the mass of the solvent:
Mass of solvent = Mass of drug / (Concentration - 1)
Substituting the given values into the formula:
Mass of solvent = 0.003 g / (0.035 - 1)
Mass of solvent = 0.003 g / (0.965)
Calculating the mass of the solvent:
Mass of solvent = 0.003 g / 0.965
Mass of solvent ≈ 0.00311 g
Therefore, the mass of the solvent that would contain 3.0 mg of the drug with a concentration of 3.5% is approximately 0.00311 grams.