Question

Which of the following statements is true of weak acids dissolved in water:

      
They are completely ionized in water

       
They are totally unionized in water

       
They are partially ionized in water

       
The dissociation constant is a function of pH

QUESTION 13

Which of the following is a hydroxide ion?

      
H3O+

       
OH-

       
HOOH

       
CH3OH2+

QUESTION 14

The following molecule is an example of which class of compounds? CH3CH2CH2COOH

      
Hydrocarbon

       
Acid

       
Alcohol

       
Aldehyde

QUESTION 15

Which of the following would not form a suitable buffer?

      
Acetic acid/ acetate (pKa 4.76)

       
Carbonic acid/ bicarbonate (pKa 3.6)

       
Bicarbonate/ carbonate (pKa 10.3)

       
Hydrochloric acid/ chloride (pKa -6.3)

1 points   

QUESTION 16

How many grams of NaCl in 10 liter to make a 0.834 M solution (NaCl MW = 58.44 g / mol)?

487

QUESTION 17

The pH of a solution that is 0.25 molar in acetic acid and 0.1 molar in sodium acetate is 4.36. What is the pKa of acetic acid?

      
4.36

       
4.76

       
7.76

       
3.76

QUESTION 18

Malate dehydrogenase converts Malate to oxaloacetate in the citric acid cycle. If the ratio of products/reactants was 1/1,000,000 in this reaction in a cell, and the standard free energy change (ΔG°’) for the reaction is 29.7 kJ mole-1, what is the ΔG?

      
-5.6 kJ mole-1

       
5.6 kJ mole-1

       
-4.8 kJ mole-1

       
4.8 kJ mole-1

       
None of the above

QUESTION 19

What is the pH of a solution where the concentration of hydrogen ions is 2 x 10-5 molar?

      
5

       
2.5

       
4.7

       
9

QUESTION 20

Bromine is one of the few elements that exists as a liquid at room temperature. At what temperature (in K) would this reaction Br2 (l) à Br2 (g) be at equilibrium. Given that at room temperature (298 K), DH = 30.91 kJ/mol, DG = 3.13 kJ/mol and DS = 0.0932 mol.K

      
298 K

       
364 K

       
253 K

       
331 K

Answer 1