PCAT Chemistry 5

Question 1

Which of the following statements about catalysts is correct?

Accepted Answer

A catalyst lowers the activation energy without being consumed

Answer

A catalyst provides an alternative reaction pathway with a lower activation energy and is regenerated at the end, so it is not consumed.

Question 2

According to Le Chatelier's Principle, if the temperature of an exothermic reaction at equilibrium is increased, the equilibrium will shift:

Accepted Answer

Toward the reactants

Answer

For an exothermic reaction, heat can be considered a product; adding heat (raising temperature) shifts the equilibrium toward the reactants to absorb the excess heat.

Question 3

The electron configuration of Fe2+ (iron II ion, atomic number 26) is:

Accepted Answer

[Ar] 3d6

Answer

Fe has [Ar] 3d6 4s2; when Fe2+ forms, the two 4s electrons are removed first, giving [Ar] 3d6.

Question 4

Which of the following is true about a reaction with a large positive equilibrium constant (K >> 1)?

Accepted Answer

The reaction strongly favors products at equilibrium

Answer

A large K value (K >> 1) indicates that at equilibrium the concentration of products greatly exceeds the concentration of reactants.

Question 5

What is the oxidation state of manganese (Mn) in KMnO4?

Accepted Answer

+7

Answer

In KMnO4, K is +1 and each O is -2 (total -8); to balance, Mn must be +7: (+1) + Mn + (-8) = 0.

PCAT - Pharmacy College Admission Test Practice Test

PCAT - Pharmacy College Admission Test Practice Test

PCAT Chemistry 5