Solution:
At the equivalence point, moles NaOH = moles benzoic acid
HA + NaOH ==> NaA + H2O where HA is benzoic acid
At the equivalence point, all the benzoic acid ==> sodium benzoate
A^- + H2O ==> HA + OH- (again, A^- is the benzoate anion and HA is the weak acid benzoic acid)
Kb for benzoate = 1x10^-14/4.5x10^-4 = 2.22x10^-11
Kb = 2.22x10^-11 = [HA][OH-][A^-] = (x)(x)/0.150
x^2 = 3.33x10^-12
x = 1.8x10^-6 = [OH-]
pOH = -log [OH-] = 5.74
pH = 14 - pOH = 8.26
Quarts of pure antifreeze must be added to 5 quarts of a 20 antifreeze solution to obtain a 50 antifreeze solution is 3.
Antifreeze solution is a solute that lowers the freezing point of the liquid in a solution.
For calculating the amount of quarts of pure antifreeze solution added can be given by:
5×20/100 + x × 100% = (x+5) × 50/100
Where, x is the amount of antifreeze required for addition and pure antifreeze is 100% of the antifreeze taken.
1 + x = (x+5) 0.5
1 + x = 0.5x + 2.5
0.5x = 1.5
x = 3
So, 3 quarts of pure antifreeze must be added to 5 quarts of a 20 antifreeze solution to obtain a 50 antifreeze solution.
Learn more about Antifreeze solution here, brainly.com/question/14619701
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Answer:
Thus the correct order would be a, b,d and then c
Explanation:
Rank of rock-forming minerals from most abundant to least abundant
1. Silicates
2. Carbonates
3. Oxides
4. Sulfates
Thus the correct order would be a, b,d and then c
C) chemical change, because burning gives new substances, but does not change nuclei of elements
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