OAT General Chemistry Principles 2

Question 1

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Angular momentum quantum number (l)

Answer

The angular momentum quantum number (l) determines the shape of the orbital (s, p, d, f).

Question 2

A buffer solution resists pH change best when the pH equals the:

Accepted Answer

pKa of the weak acid

Answer

A buffer is most effective when pH = pKa, where the concentrations of weak acid and conjugate base are equal (Henderson-Hasselbalch equation).

Question 3

What is the hybridization of the central carbon in CO2?

Accepted Answer

sp

Answer

Carbon in CO2 forms two double bonds with no lone pairs, resulting in sp hybridization and linear geometry.

Question 4

During a reaction, ΔG = 0. This indicates the reaction is:

Accepted Answer

At equilibrium

Answer

When ΔG = 0, the system is at chemical equilibrium and the forward and reverse rates are equal.

Question 5

Which of the following exhibits the highest boiling point due to intermolecular forces?

Accepted Answer

NH3

Answer

NH3 has the highest boiling point because it can form hydrogen bonds, which are stronger than the London dispersion forces present in the others.

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