GACE Chemistry 3

Question 1

Which quantum number describes the shape of an electron's orbital?

Accepted Answer

Angular momentum quantum number (l)

Answer

The angular momentum quantum number (l) defines orbital shape: l=0 is s, l=1 is p, l=2 is d.

Question 2

A buffer solution resists changes in pH when small amounts of acid or base are added. Which combination would create an effective buffer near pH 7?

Accepted Answer

H₂PO₄⁻ and HPO₄²⁻

Answer

A buffer requires a weak acid and its conjugate base; H₂PO₄⁻/HPO₄²⁻ is a conjugate pair with pKa near 7.2.

Question 3

During electrolysis of molten NaCl, what forms at the cathode?

Accepted Answer

Na metal

Answer

The cathode is the site of reduction; Na⁺ ions gain electrons to form Na metal.

Question 4

Which of the following correctly identifies a characteristic of transition metals?

Accepted Answer

They often exhibit multiple oxidation states

Answer

Transition metals can lose varying numbers of d electrons, allowing them to exist in multiple oxidation states.

Question 5

What does the rate law for a reaction reveal about the reaction mechanism?

Accepted Answer

Which step is the slowest (rate-determining) step

Answer

The rate law reflects the concentrations involved in the slowest elementary step, revealing the rate-determining step.

GACE - Georgia Assessments for the Certification of Educators Practice Test