OAT General Chemistry Principles 5

Question 1

Which of the following best describes the relationship between Kp and Kc for a gas-phase reaction?

Accepted Answer

Kp = Kc(RT)^Δn

Answer

The relationship is Kp = Kc(RT)^Δn, where Δn is the change in moles of gas (products minus reactants).

Question 2

What type of radioactive decay results in an increase in atomic number by 1?

Accepted Answer

Beta-minus decay

Answer

In beta-minus decay, a neutron is converted to a proton, emitting an electron, which increases the atomic number by 1.

Question 3

A 1 L solution contains 0.5 mol of HF (Ka = 7.2 × 10⁻⁴). Compared to 0.5 M HCl, the HF solution has:

Accepted Answer

A higher pH

Answer

HF is a weak acid that only partially dissociates, producing fewer H⁺ ions than strong acid HCl at the same concentration, resulting in a higher pH.

Question 4

Which of the following has the greatest electronegativity?

Accepted Answer

F

Answer

Fluorine has the highest electronegativity (3.98 on the Pauling scale) of all elements.

Question 5

The standard electrode potential (E°) of a cell reaction is +1.10 V. This reaction is:

Accepted Answer

Spontaneous, ΔG° < 0

Answer

A positive E°cell corresponds to a negative ΔG° (ΔG° = −nFE°), indicating a spontaneous reaction under standard conditions.

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