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ionic activity, a+-

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Reply 20
Original post by lucasleiva
may i know is my method of calculating the mean ionic activity is right or wrong?i multiply the activity coefficient with the molarity (0.0325M)


Yeah that's right. It's calculating the activity coefficient that is tricky.
Reply 21
Original post by alow
Yeah that's right. It's calculating the activity coefficient that is tricky.


i see, thank you. but i have another way of calculating the mean ionic activity, which is [(0.0325 x 4 )^4 (0.0325)]^(1/5) x mean activity coefficient.

and i get a different value, is this method correct?
Reply 22
Original post by lucasleiva
i see, thank you. but i have another way of calculating the mean ionic activity, which is [(0.0325 x 4 )^4 (0.0325)]^(1/5) x mean activity coefficient.

and i get a different value, is this method correct?


I can't tell what that thing is by looking at the numbers. What is the name of the model you used?
Reply 23
Original post by alow
I can't tell what that thing is by looking at the numbers. What is the name of the model you used?


sorry i couldnt tell. But im given this sets of formula by my teacher:Mean activity, a+- = (a+.a-)^(1/2) mean activity coefficient, y+- = (y+.y-)^(1/2)
Mean molality, m+- = (m+.m-)^(1/2) a+- = (y+-)(m+-)
Reply 24
Original post by lucasleiva
sorry i couldnt tell. But im given this sets of formula by my teacher:Mean activity, a+- = (a+.a-)^(1/2) mean activity coefficient, y+- = (y+.y-)^(1/2)
Mean molality, m+- = (m+.m-)^(1/2) a+- = (y+-)(m+-)


Use the Davies model to calculate the activity coefficients and activities for each ion, then use those formulae to calculate what the question asks for.
Reply 25
Original post by alow
Use the Davies model to calculate the activity coefficients and activities for each ion, then use those formulae to calculate what the question asks for.


those formulae can be used? since i dun have the molality

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