Energy and Rates of Reaction

The energy needed for substance to initiate reaction is called...

• Initiation energy

• Propagation energy

• Activation energy

• Enthalpy

Combustion is one of the most common exothermic reaction. What is the obligatory reactant in combustion reaction?

• CO₂

• H₂O

• O₂

• CH₄

From options below, which one is an exothermic reaction?

• Photosynthesis

• Melting ice cube

• Freezing water

• Rusting iron

When the value of ΔH is negative, which one(s) from below is/are true?

• The reaction is fast

• The reaction releases energy

• It is a combustion reaction

• The energy of product is lower than reactant

Powdered sugar dissolves more easily than rock sugar. Which factor affects this process?

• Surface area

• Concentration

• Temperature

• Catalyst

Iron dissolves faster in warmer acid than colder acid. This happens because...

• Warmer acid leads to endothermic reaction

• More molecules have enough energy to react

• Warm iron are brittle

• Solubility of iron in water increase

Which one(s) from below is/are true for catalyst?

• The amount of catalyst will not be reduced when reaction ends

• Catalyst makes reaction happens faster

• Catalyst increases the activation energy

• Catalyst contributed nothing to the reaction

When KCl salt is dissolved in water, the water becomes colder. By that information, we know that the solvation of KCl is...

• Endothermic reaction

• Endothermic process

• Exothermic reaction

• Exothermic process

Wind is an alternative energy source, and we can get the energy by using windmill. What is the type of energy change in windmill?

• Potential to Kinetic

• Mechanic to Chemical

• Kinetic to Electricity

• Heat to Magnetic

Take a look at this reaction. If the bond energy of N≡N, O=O, and N=O is 941 kJ/mol, 495 kJ/mol, and 607 kJ/mol respectively, what is the enthalpy change?

• +2043 kJ

• +222 kJ

• +829 kJ

• 0 kJ