1 for specific request mail
MCAT Chemistry Practice Questions and Correct
Answers | Latest Update
Suppose a nanotechnological innovation allows every single charged ion
to be precisely identified and removed from a small volume of water.
Which of the following describes Ka for the water at the end of the
process, assuming that the filtered water is given time to re-equilibrate?
A) 1
B) 0
Assignment Expert
C) 10^-14
Guru01 - Stuvia
D) 10^-7 Ans: C) 10^-14
The auto ionization of water occurs naturally due to attractive forces
between constituents of water molecules. Even if all ions are removed
from a sample of water (including hydronium ions), a short time later,
2026
the water will re-ionize until it approaches an equilibrium concentration
of ions. In equilibrium, Ka = Kw = 10^-14.
©
Suppose an acid HA has a dissociation constant Ka = 1 x 10^-1. It is
mixed into a buffered solution, and its equilibrium concentration is [HA]
= 0.1 M. If the concentration of its conjugate base is 10 M, what is the pH
of the solution?
A) 4
B) 3
C) 1
D) 8 Ans: B) 3
Recall the Henderson-Hasselbach equation, which is valid for the buffer
solution in the problem.
, 2 for specific request mail
Recall that pKa = -log(Ka). In this problem, pKa = 1.
Solving for the other term, you have log(10/0.1) = log(100) = 2.
pH = 1 + 2 = 3.
What is the pH of a solution with [H3O+] = 10^4 M?
A) -4
B) 10
C) -8
Assignment Expert
D) 4 Ans: A) -4
Guru01 - Stuvia
pH = -log[H3O+] = -log(10000) = -4
Which of the following would have the weakest conjugate acid?
A) a weak acid
2026
B) a strong acid
©
C) a strong base
D) a weak base Ans: C) a strong base
When a strong acid or base equilibrates in solution, equilibrium is driven
to the right, towards the products. This implies that, if the products were
put into a new solution, they would barely react because equilibrium
disfavors the spontaneous formation of strong acid or strong base
molecules in solution. Strong bases ionize almost irreversibly, so their
products are weak conjugate acids.
Suppose a large organic molecule X is classified as a Lewis acid, while
another large molecule Y is classified as a Bronsted-Lowry acid. Which of
the following most accurately describes a similarity in their behaviors in
solution?
MCAT Chemistry Practice Questions and Correct
Answers | Latest Update
Suppose a nanotechnological innovation allows every single charged ion
to be precisely identified and removed from a small volume of water.
Which of the following describes Ka for the water at the end of the
process, assuming that the filtered water is given time to re-equilibrate?
A) 1
B) 0
Assignment Expert
C) 10^-14
Guru01 - Stuvia
D) 10^-7 Ans: C) 10^-14
The auto ionization of water occurs naturally due to attractive forces
between constituents of water molecules. Even if all ions are removed
from a sample of water (including hydronium ions), a short time later,
2026
the water will re-ionize until it approaches an equilibrium concentration
of ions. In equilibrium, Ka = Kw = 10^-14.
©
Suppose an acid HA has a dissociation constant Ka = 1 x 10^-1. It is
mixed into a buffered solution, and its equilibrium concentration is [HA]
= 0.1 M. If the concentration of its conjugate base is 10 M, what is the pH
of the solution?
A) 4
B) 3
C) 1
D) 8 Ans: B) 3
Recall the Henderson-Hasselbach equation, which is valid for the buffer
solution in the problem.
, 2 for specific request mail
Recall that pKa = -log(Ka). In this problem, pKa = 1.
Solving for the other term, you have log(10/0.1) = log(100) = 2.
pH = 1 + 2 = 3.
What is the pH of a solution with [H3O+] = 10^4 M?
A) -4
B) 10
C) -8
Assignment Expert
D) 4 Ans: A) -4
Guru01 - Stuvia
pH = -log[H3O+] = -log(10000) = -4
Which of the following would have the weakest conjugate acid?
A) a weak acid
2026
B) a strong acid
©
C) a strong base
D) a weak base Ans: C) a strong base
When a strong acid or base equilibrates in solution, equilibrium is driven
to the right, towards the products. This implies that, if the products were
put into a new solution, they would barely react because equilibrium
disfavors the spontaneous formation of strong acid or strong base
molecules in solution. Strong bases ionize almost irreversibly, so their
products are weak conjugate acids.
Suppose a large organic molecule X is classified as a Lewis acid, while
another large molecule Y is classified as a Bronsted-Lowry acid. Which of
the following most accurately describes a similarity in their behaviors in
solution?
