calculation of ionisation percentage

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anto007
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calculation of ionisation percentage

Post by anto007 »

Hi, could you help me with this exercise, please?
"The pH of a 0.6 M solution of a weak acid is 4.0. What is the percentage of ionised acid?"
Thanks.
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ChenBeier
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Re: calculation of ionisation percentage

Post by ChenBeier »

Calculate the Concentration of H+ of the acid from pH.
This value divide through the Concentration of the whole acid x 100% gives percentage of dissociation.
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anto007
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Re: calculation of ionisation percentage

Post by anto007 »

I did so:
pH= -log_10([H+])= 10^-4
%=((10^-4)/(0,6))*100=0,016

but I do not get the expected result (0.02%)
Should I round up?
The mind is like a parachute, it only works if it opens. -A. Einstein
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ChenBeier
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Re: calculation of ionisation percentage

Post by ChenBeier »

0,0166 % is correct
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anto007
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Re: calculation of ionisation percentage

Post by anto007 »

thanks :)
The mind is like a parachute, it only works if it opens. -A. Einstein
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