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# ionic activity, a+-

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1. (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.
2. (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?
3. (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?
4. (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+-)
5. (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.
6. (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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