hello, I am new to this. I am studying for my PTCB and have come accross a question that has really got me stumped for some reason. I wondering if anyone could shed some light for me. What is the answer and or steps to determine the answer.Any help would be greatly apreciated. Thank you. :?:
How many milliliters of active ingredient are contained in a pint of 15% v/v solution?
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Pharmacy Calculations
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Dear convert-me.com forum visitors,
Our forum has been available for many years. In September 2014 we decided to switch it to read-only mode. Month after month we saw less posts with questions and answers from real people and more spam posts. We were spending more and more resources cleaning the spam until there were less them 1 legitimate message per 100 spam posts. Then we decided it's time to stop.
All the posts in the forum will be available and searchable. We understand there are a lot of useful information and we aren't going to remove anything. As for the new questions, you can always ask them on convert-me.com FaceBook page
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Re: Pharmacy Calculations
by Guest » Mon Jan 09, 2012 6:42 am
2012.1.8
Lab experiments and types of research often require preparation of chemical solutions in their procedure. We look at preparation of these chemical solutions by weight (w/v) and by volume (v/v).
Using percentage by volume (v/v) When the solute is a liquid, it is sometimes convenient to express the solution concentration as a volume percent.
The formula for volume percent (v/v) is: [Volume of solute (ml) / Volume of solution (ml)] x 100
ex. Make 1000ml of a 5% by volume solution of ethylene glycol in water.
First, express the percent of solute as a decimal: 5% = 0.05
Multiply this decimal by the total volume: 0.05 x 1000ml = 50ml (ethylene glycol needed).
Subtract the volume of solute (ethylene glycol) from the total solution volume:
1000ml (total solution volume) - 50ml (ethylene glycol volume) = 950ml (water needed)
Dissolve 50ml ethylene glycol in a little less than 950ml of water. Now bring final volume of solution up to 1000ml with the addition of more water. (This eliminates any error because the final volume of the solution may not equal the calculated sum of the individual components).
So, 50ml ethylene glycol / 1000ml solution x100 = 5% (v/v) ethylene glycol solution.
Lab experiments and types of research often require preparation of chemical solutions in their procedure. We look at preparation of these chemical solutions by weight (w/v) and by volume (v/v).
Using percentage by volume (v/v) When the solute is a liquid, it is sometimes convenient to express the solution concentration as a volume percent.
The formula for volume percent (v/v) is: [Volume of solute (ml) / Volume of solution (ml)] x 100
ex. Make 1000ml of a 5% by volume solution of ethylene glycol in water.
First, express the percent of solute as a decimal: 5% = 0.05
Multiply this decimal by the total volume: 0.05 x 1000ml = 50ml (ethylene glycol needed).
Subtract the volume of solute (ethylene glycol) from the total solution volume:
1000ml (total solution volume) - 50ml (ethylene glycol volume) = 950ml (water needed)
Dissolve 50ml ethylene glycol in a little less than 950ml of water. Now bring final volume of solution up to 1000ml with the addition of more water. (This eliminates any error because the final volume of the solution may not equal the calculated sum of the individual components).
So, 50ml ethylene glycol / 1000ml solution x100 = 5% (v/v) ethylene glycol solution.
- Guest
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