A pharmacy technician is filling a prescription for a liquid medication at a concentration of 250 mg/5 ml. How many ml are needed to provide a dosage of 1 gram?

To determine the correct volume of liquid medication needed to provide a dosage of 1 gram, start by converting grams to milligrams, since the concentration is given in mg/ml.

1 gram is equivalent to 1000 milligrams. The concentration of the medication is 250 mg in 5 ml. To find out how many ml are required to provide 1000 mg, we can set up a proportion based on the concentration.

First, we find out how many mg are in 1 ml:

250 mg / 5 ml = 50 mg/ml

Now, to calculate how many ml are needed for 1000 mg:

1000 mg / (50 mg/ml) = 20 ml

Thus, the calculation shows that to deliver a total dosage of 1000 mg (or 1 gram) of the medication, 20 ml of the liquid is required. The reasoning is based on the direct relationship between concentration and volume, leading to a straightforward calculation.