PLEASE HELP! (8.01 MC)
1 answer:
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The concentration after dilution is 1.4%.
We are aware that concentration and volume are related to each other by the formula -
=
, where we have initial concentration and volume on Left Hand Side and final concentration and volume on Right Hand Side.
Keep the values to calculate final concentration.
= (53.5 × 5.4)/205.0
Performing multiplication on Right and Side
= 288.9/205.0
Performing division on Right Hand Side
= 1.4%
Hence, the final concentration is 1.4%.
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The complete question is -
A 53.5 mL sample of an 5.4 % (m/v) KBr solution is diluted with water so that the final volume is 205.0 mL.
Calculate the final concentration and express your answer to two significant figures and include the appropriate units.
Answer:
The pKa of the conjugate acid is 17.7
Explanation:
If hydrogen is removed from water, the equilibrium concentration of the conjugate acid according to the information given in the question becomes,
Kₐ = [OH⁻]/[H₂O]
Now, we determine the equivalent pKa
pKa = -log[ka]
pKa = -log[100]
pKa = -2
Removal of hydrogen from water is reversible as shown below;
H₂O ⇄ OH⁻ + H⁺
15.7 -2
This reaction is reversible, and the difference in pKa = pKa[H₂O] - pKa[H⁺];
pKa of the conjugate acid = 15.7 - (-2) = 17.7
The pKa of the conjugate acid is 17.7