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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: addy925 on January 16, 2021, 11:24:03 PM

Title: concentration of standard solutions
Post by: addy925 on January 16, 2021, 11:24:03 PM

I made a set of standard solutions and was wondering if this is the correct way to calculate the concentration for one of them.

ex. Flask has 5 mL of SO3- (1e-04 g/mL) and 5 mL of SO4- (2e-04 g/mL) and is diluted to 50 mL.

To calculate the concentration of SO3-:
DF = V2/V1 = 50/5 = 10

DF = C1/C2
10 = (1e-04)/C2
C2 = 1e-05 g/mL

Same thing for SO4-.

If anyone could point me in the right direction, that'd be great. Thanks in advance!

Title: Re: concentration of standard solutions
Post by: AWK on January 17, 2021, 12:32:21 AM

You dilute 5 ml, not 1 ml.

Title: Re: concentration of standard solutions
Post by: addy925 on January 17, 2021, 01:50:06 AM

so would you change C1 to 5*(1e-04)?
Thanks!

Title: Re: concentration of standard solutions
Post by: mjc123 on January 17, 2021, 10:25:16 AM

I don't get AWK's point. The mass is 5e-4 g, but the concentration is (5e-4)/5 = 1e-4 g/ml. If the 5 ml is diluted to a final volume of 50 ml, it is diluted tenfold, so the concentration is 1e-5 g/ml.