Answer:
85.6
Explanation:
(72 x 85) + (28 x 87)
-----------------------------
100
= 85.56
= 85.6 (3 s.f.)
Answer:
Ka3 for the triprotic acid is 7.69*10^-11
Explanation:
Step 1: Data given
Ka1 = 0.0053
Ka2 = 1.5 * 10^-7
pH at the second equivalence point = 8.469
Step 2: Calculate Ka3
pKa = -log (Ka2) = 6.824
The pH at the second equivalence point (8.469) will be the average of pKa2 and pKa3. So,
8.469 = (6.824 + pKa3) / 2
pKa3 = 10.114
Ka3 = 10^-10.114 = 7.69*10^-11
Ka3 for the triprotic acid is 7.69*10^-11
Answer:
The original concentration of ethanol was 18 % (v/v)
Explanation:
For the analysis of a sample, mostly dilutions are made of the original concentrated sample. The analysis results obtained from the diluted sample are then calculated for the concentrated samples.
According to the given data, the wine sample was diluted 75 times. This means that the initial concentration of ethanol was 75 times more than the final concentration i.e. 0.24 % (v/v). So mathematically:
original concentration (v/v)= final concentration (v/v) x times diluted
original concentration (v/v)= 0.24 % x 75
original concentration (v/v) = 18 %
