Chemistry Test Physical Chemistry 2

Question 1

Which thermodynamic quantity remains constant in an adiabatic process?

Accepted Answer

Heat (q = 0)

Answer

An adiabatic process is defined by zero heat exchange between the system and surroundings (q = 0).

Question 2

The van't Hoff factor (i) for a strong electrolyte like NaCl dissolved in water is approximately:

Accepted Answer

2

Answer

NaCl fully dissociates into Na⁺ and Cl⁻, giving two particles per formula unit, so i ≈ 2.

Question 3

According to the Arrhenius equation, plotting ln(k) vs 1/T yields a slope of:

Accepted Answer

-Ea/R

Answer

The Arrhenius equation ln(k) = ln(A) − Ea/R · (1/T) shows the slope equals −Ea/R.

Question 4

What does a negative value of ΔG indicate about a chemical reaction?

Accepted Answer

The reaction is spontaneous

Answer

A negative Gibbs free energy change (ΔG < 0) indicates the reaction proceeds spontaneously under constant temperature and pressure.

Question 5

Which colligative property is used to determine the molar mass of a polymer dissolved in solution?

Accepted Answer

Osmotic pressure

Answer

Osmotic pressure is preferred for high-molar-mass polymers because it produces measurable pressure differences even at very low concentrations.

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