Comprehension Level 2 (Low)

1.       Label the missing components in the following energy diagram showing an exothermic reaction. (3 Marks)

a

b

c

d

Ea

Reactants

Products

Answer explanation

2.    Fill in the missing components of the equation: (a)   and determine whether the reaction is endothermic or exothermic (3 Marks)

• CO2 + 2H2O, Exothermic
• C2H6 + O2, Endothermic
• CH4 + O2, Exothermic
• C3H8 + O2, Endothermic

Answer explanation

On top, label each graph as exothermic or endothermic reaction. On bottom, label as an example steel wool or NH₄Cl + H2O + heat ---> NH₄+ + Cl-.

a

b

c

d

Steel Wool Combustion

Exothermic Reaction

NH₄Cl + H2O + heat ---> NH₄+ + Cl-

Endothermic Reaction

1.       Label the correct direct route, indirect routes for the provided reaction cycle diagram (3 Marks)

a

b

c

Indirect Route 1

Direct Route

Indirect Route 2

What does Hess’s Law state? 

• The total enthalpy change of reaction depends on the path taken 

• Only exothermic reactions obey Hess’s Law 

• None of the above

• The total enthalpy change is independent of the path taken 

Hess’s Law is based on the principle of ________

An exothermic reaction has a _______ enthalpy change

The unit used for measuring enthalpy change is ________

When a reaction releases energy, the products have ________ energy than the reactants

A calorimeter is a device used to measure ________