SOLUTION: What is the % w/v of 8g of dextrose in 50ml?

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Question 1108137: What is the % w/v of 8g of dextrose in 50ml?
Found 3 solutions by Collinwilfixyouuprealnice, KMST, ikleyn:
Answer by Collinwilfixyouuprealnice(44) About Me  (Show Source):
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
If you work in a life sciences lab, you find concentrations listed as %w/v sometimes.
For %w/v, we use grams an milliliters as if they were the same unit.

If the total volume of the solution is 50mL,
then the % w/v is 8%2F50=16%2F100=highlight%28%2216%25%22%29 .
That is where a math problem ends.

That solution will NOT weigh 58 g, so its %w/w would NOT be
8g%2F%2258+g%22=approximately+0.138 which would be 13.8%2F100=%2213.8%25+w%2Fw%22 .
That solution will be more dense than water, but not by much.
Its density at common room temperatures will be 1.06 g/mL. (I look that up when I need to).
So, your 16% w/v solution would weigh %2850mL%29%28%221.06+g+%2F+mL%22%29=about+52.8g ,
with a w/w ratio of 8%2F52.8=about0.152 .
That approximate ratio is 15.2%2F100=%2215.2%25%22 , and that is the %w/w.

A DIFFERENT PROBLEM:
However, if you mix 8g dextrose and 50mL of water, for a final weight of about 6g%2B50g=8g ,
that is a different math problem.
If you are a pharmaceutical formulator or a chemical engineer that is your problem.
The final volume will be more than 50mL, but not quite 58mL.
The concentration as %w/w would be 8g%2F%2258+g%22=approximately+0.138 ,
which is 13.8%w/w.
A table of densities, or "specific gravities" would tell you that its density would be about %221.06+g+%2F+mL%22 too.
That means its volume would be
58g%2F%221.06+g+%2F+mL%22=about54.7mL .
That would make its (solute weight)/(total volume) ratio
about 8%2F54.7=about+0.146
and its %w/v concentration 14.6%2F100=%2214.6%25%22 .

Answer by ikleyn(52867) About Me  (Show Source):