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You are ordered to administer 20 mg of Medication A. The vial shows a concentrationof 0.5%. How many mL will you need to administer in order to deliver the correctdose?

User Edvige
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1 Answer

21 votes
21 votes

The concentration of the vial is 0.5 %. We will suppose that it is % w/v. The concentrarion % w/v is defined as:

% w/v = mass of solute in g/volume of solution in mL * 100

We have to find the mL that we have to administer to deliver 20 mg. Let's convert those mg into g. We know that there are 1000 mg in 1 g.

1000 mg = 1 g

mass of solute in g = 20 mg * 1 g/(1000 mg)

mass of solute in g = 0.020 g

Now that we know the concentration of the solution and the mass in grams of the medication, we can find the volume in mL.

% w/v = mass of solute in g/volume of solution in mL * 100

0.5 = 0.020 / volume of solution in mL * 100

volume of solution in mL = 0.5/(100 * 0.020)

volume of solution in mL = 0.25 mL

Answer: we need to administer 0.25 ml

User LukasMac
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