5. The ionic dissociation of water is given by the following reaction: The ΔH for the reaction is 58kJ/mol. The Kw for the reaction at 25°C is 10^-14. Is a pH of 7 acidic or basic at 30°C?
2H2O(l) H30+(aq) + OH-(aq)
What is the pH? I used the nerst equation but I'm not getting the right answer.
Test 2
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Re: Test 2
You have to use the Van't Hoff equation:
Plug in values:
Solve for :
Since for a neutral solution :
Therefore, a neutral pH is 6.95 at 30°C. Since 7 is greater than 6.95, a pH of 7 is basic at 30°C.
Plug in values:
Solve for :
Since for a neutral solution :
Therefore, a neutral pH is 6.95 at 30°C. Since 7 is greater than 6.95, a pH of 7 is basic at 30°C.
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Re: Test 2
The above work shows 2pH because they are showing that in a neutral solution, pH=7 and pOH=7, so because they have the same value, you can take the equation
pH + pOH = 14
and substitute pH for the pOH and get,
pH + pH = 14 or 2pH = 14
pH + pOH = 14
and substitute pH for the pOH and get,
pH + pH = 14 or 2pH = 14
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Re: Test 2
So can we assume we always assume that when the pH is 7 then it will be pH + pH = 14 in which we will divide by 2.
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