General Chemistry Principles Flashcards

Which of the following solutions has the lowest freezing point? (Assume complete dissociation for electrolytes.)

Answer: 1 m CaCl2

CaCl2 dissociates into 3 ions (1 Ca²⁺ + 2 Cl⁻), giving the highest van't Hoff factor and the greatest freezing point depression.

According to Le Chatelier's principle, increasing pressure on the equilibrium N2(g) + 3H2(g) ⇌ 2NH3(g) will:

Answer: Shift equilibrium to the right

Increasing pressure favors the side with fewer moles of gas; the product side has 2 moles versus 4 moles on the reactant side.

The electron configuration of Fe²⁺ is:

Answer: [Ar] 3d6

Iron (Fe) is [Ar] 3d6 4s2; losing 2 electrons first removes the 4s electrons, giving Fe²⁺ = [Ar] 3d6.

A reaction has ΔH = +50 kJ/mol and ΔS = +100 J/(mol·K). At what temperature does the reaction become spontaneous?

Answer: Above 500 K

Setting ΔG = ΔH − TΔS = 0, T = ΔH/ΔS = 50,000 J / 100 J/K = 500 K; spontaneous above 500 K.

Which type of isomers are non-superimposable mirror images of each other?

Answer: Enantiomers

Enantiomers are non-superimposable mirror images that differ only in the arrangement of groups around a chiral center.

In the reaction 2H2O2 → 2H2O + O2, hydrogen peroxide acts as:

Answer: Both oxidizing and reducing agent

H2O2 undergoes disproportionation: one molecule is oxidized (O: −1→0 in O2) and another is reduced (O: −1→−2 in H2O).

What is the pH of a 0.01 M HCl solution?

Answer: 2

HCl is a strong acid that fully dissociates; [H⁺] = 0.01 M = 10⁻² M, so pH = −log(10⁻²) = 2.