If the pH of a weak acid solution is 2.500 and the solution has a concentration of 0.100M, what is the Ka of the weak acid HA?
1 answer:
Answer:
The Kₐ of the weak acid is 1.033×10⁻⁴
Explanation:
The dissociation of a weak acid in aqueous solution is limited to about 5 to 10%
The acid dissociation reaction is given as follows;
HA (aq) + H₂O (l) → H₃O⁺(aq) + A⁻ (aq)
Given that the pH = 2.5, we have
pH = -log₁₀[H₃O⁺] = 2.5
∴ [H₃O⁺] = 10^(-2.5) = 0.0031623
Kₐ = [H₃O⁺][A⁻]/[HA] = (0.0031623^2)/(0.1 - 0.0031623) = 1.033×10⁻⁴
The acid dissociation constant, Kₐ for weak acid is very low as obtained
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Answer:
<em>Option C: 4.54 x </em><em> KJ/mol of nuclei</em>
<em>Note: </em>Here in this question option C is not correctly put. It is 4.54 x rather than 4.54 x
.
Explanation:
If mass defect is known, then nuclear binding energy can easily be calculated, here's how:
First step is to convert that mass defect into kg.
Mass defect = 5.0446 amu
Mass defect = 5.0466 x 1.6606 x
Because 1 amu = 1.6606 x Kg.
<em>Mass defect = 8.383 x </em><em> kg.</em>
Now, we need to find out it's energy equivalent by using following equation:
Using the equation E = mc²:
where c= 3.00 x m/s²
E = (8.383 x ) x (3.00 x
)²
E = 7.54 x J this energy is in Joules but nuclear binding energy is usually expressed in KJ/mol of nuclei. Let's convert it:
(7.54 x Joule/nucleus)x(1 kJ/1000 Joule)x(6.022 x
nuclei/mol) =
<em>4.54 x </em><em> kJ/mol of nuclei .</em>
E = <em>4.54 x </em><em> kJ/mol of nuclei .</em> So, this is the nuclear binding energy of that atom, which is option C.
<em>Note:</em> Here in this question option C is not correctly put. It is 4.54 x rather than 4.54 x