IB Chemistry 5

Question 1

Which of the following best describes an exothermic reaction?

Accepted Answer

ΔH < 0 and energy is released to surroundings

Answer

In an exothermic reaction, ΔH is negative because the system releases energy to the surroundings, causing the temperature to rise.

Question 2

In titration, what is the equivalence point?

Accepted Answer

The point where moles of acid equal moles of base

Answer

The equivalence point is where the moles of titrant added exactly neutralize the moles of the analyte, not necessarily at pH 7.

Question 3

Which of the following is the correct definition of molarity?

Accepted Answer

Moles of solute per liter of solution

Answer

Molarity (M) is defined as the number of moles of solute divided by the volume of solution in liters.

Question 4

What does the Hess's Law state?

Accepted Answer

The total enthalpy change of a reaction is the same regardless of the route taken

Answer

Hess's Law states that the total enthalpy change of a reaction is independent of the pathway, depending only on initial and final states.

Question 5

Which of the following represents a homogeneous mixture?

Accepted Answer

Saltwater

Answer

Saltwater is a homogeneous mixture because the solute (salt) is uniformly distributed throughout the solvent (water) at the molecular level.

IB - International Baccalaureate Practice Test