dosage calculations help

[Rhianonin]

I am trying to practice for a dosage calculations workshop to enter the nursing program. its online and there is not a lot of guidance. I was wondering if someone can help with this question.

the nurse wants to give 2g of magnesium sulfate and has available a medication labeled 50% magnesium sulfate in 20 mL.

How many mL will the nurse administer?

I am confused when I try to make it into a dimensional analysis problem. Am I missing something terribly obvious? I set it up as this

2g magnesium sulfate|20mL

---

1 | .5 magnesium sulfate

Can someone help me out? Thank you!

[Rhianonin]

sorry for the formatting. I couldn't figure out how to write the problem out with the vertical lines in the proper places.

[miss__RN]

always set up the question: desire / have

start with with you have available, which in this case is 2 g of Mg

then, put the units of what they are looking for on top (the last part of the question)

the units should always cross out which helps when setting up the problem.

2g ( 20 ml

-------

.5 g )

hope this helps!

[Rhianonin]

So the 50% magnesium sulfate means .5g? because in the problem the unit g was never specified it was only written as "available medication labeled 50% magnesium sulfate in 20 mL" is the g assumed?

[chare]

So the 50% magnesium sulfate means .5g? because in the problem the unit g was never specified it was only written as "available medication labeled 50% magnesium sulfate in 20 mL" is the g assumed?

No, the 50% does not equal 0.5 g. The 50% denotes a percent strength solution. In a percent strength solution the % designates the number of grams of substance diluted to a total volume of 100 mL. If you have a 50% solution of magnesium sulfate, how many grams are in 100 mL of solution? Once you calculate this value, you should have all of the information you need to solve this.

If you haven't yet done so, you might consider reviewing the attachments on the first two posts in this thread; particularly the second post.

Best wishes.

ETA: https://allnurses.com/pre-nursing-student/master-your-drug-1148937.html