IB Chemistry Energetics Quiz

Relative rates of reaction depend on

I. Temperature

II. Concentration / pressure of reactants and products

III. Presence of catalyst

• I and II

• I and III

• II and III

• I,II and III

When the concentration of products is greater than the concentration of reactants:

I. Reaction goes almost to completion

II. Kc < 1

III. Reaction hardly proceeds

IV. Kc > 1

• I and II

• I and III

• III and IV

• I and IV

What is it called when reactants and products are present in one phase?

• Heterogeneous equilibrium

• Gaseous equilibrium

• Homogenous equilibrium

• Dynamic equilibrium

In combustion, what happens to the position of equilibrium when the temperature increases?

• Equilibrium position moves to the left as products are favoured.

• Equilibrium position moves to the right as products are favoured.

• Equilibrium position moves to the left reactants are favoured.

• Equilibrium position moves to the right as reactants are favoured.

There are 4 moles of gaseous reactants and 3 moles of gaseous products. What happens to the position of equilibrium and Kc when the pressure increases?

• Equilibrium position moves towards the products and Kc increases.

• Equilibrium position moves towards the reactants and Kc does not change.

• Equilibrium position moves towards the products and Kc does not change.

• Equilibrium position moves towards the reactants and Kc does not increases.

Solutions of two chemicals are mixed. A reaction occurs and the temperature change is measured. Which statement is correct?

• If the reaction is endothermic, the temperature decreases and energy is taken in.

• If the reaction is endothermic, the temperature increases and energy is given out.

• If the reaction is exothermic, the temperature decreases and energy is given out.

• If the reaction is exothermic, the temperature increases and energy is taken in.

Which is an endothermic process?

• burning hydrogen

• distilling petroleum

• reacting potassium with water

• using petrol in a motor car engine

Below are some standard enthalpy changes including the standard enthalpy of combustion of nitroglycerine, C3H5N3O9

½ N2(g) + O2(g) -> NO2(g) DH = +34 kJ mol–1

C(s) + O2(g) -->CO2(g) DH= –394 kJ mol–1

H2(g) + ½O2(g)-->H2O(g) DH= –242 kJ mol–1

C3H5N3O9(l) + O2(g) -->3CO2(g) + H2O(g) + 3NO2(g) DH = –1540 kJ mol–1

Use the standard enthalpy changes given above to calculate the standard enthalpy of formation of nitroglycerine.

• +8kJmol–1

• +9kJmol–1

• +7kJmol–1

• +3kJmol–1

• -2160 kJ mol–1

• – 1561 kJ mol–1

• -3210 kJ mol–1

• +2103 kJ mol–1

Define the term standard enthalpy of formation, ∆Hf⁰

• The enthalpy change when 1 mol of a compound is completely burnt in oxygen under standard conditions, all reactants and products being in their standard states

• The enthalpy change when 1 mol of a compound is completely burnt under standard conditions, all reactants and products being in their standard states

• The enthalpy change of reaction when 1 mol of a compound is completely burnt under standard conditions, all reactants and products being in their standard states

• The enthalpy change of combustion when 1 mol of a compound is completely burnt under standard conditions, all reactants and products being in their standard states