A doctor has ordered 225 mg of morphine. It is only available as a 0.40 g/mL solution. How many mL of solution are required?

Answer 1

Since the desired dose is given as mg (225 mg), let us convert the available solution into these units. 0.40 g/ml = 400 mg/ml.

Now, 225 mg x 1 ml/400 mg = 0.563 ml = 0.5 ml

Answer 2

I'n not a chemistry whiz, but here is my take on the problem.

225 mg = ..225g

If morphine is available only in .40g/mL, then divide.

..225g/(.40g/mL) = .225g*mL/.40g

the grams unit cancel out, so you are left with .5625 mL

Answer 3

You need to covert mg (milligrams) to g (grams). There are 1000 mg in a g. So 225 mg is .225 grams.

Now set up your ratio. .4g/1ml = .225g/x ml.

That's .4 grams over 1 milliliter equals .225 grams over x milliliters, x being the unknown.

Now you cross-multiply. .4x = .225

Divide both sides by .4.

x = .5625 ml