Endothermic & Exothermic

Which of the following is an exothermic reaction?

• Boiling

• Melting

• Diffusion

• Combustion of methane in air

Which process is endothermic?

• the formation of a hydrogen-chlorine bond

• the formation of rust

• the formation of water from ice

• the formation of water from oxygen and hydrogen

Which process is exothermic?

• burning petrol in a car engine

• cracking of oil fractions

• fractional distillation of oil

• melting bitumen for roads

Which of the following is an endothermic reaction?

• Combustion of fuel

• Photosynthesis

• Respiration

• Freezing

Which of the following is an endothermic process?

• the addition of water to anhydrous copper (II) sulfate

• the combustion of ethanol in air

• the formation of a carbohydrate and oxygen from carbon dioxide and water

• the oxidation of carbon to carbon dioxide

Which statement is correct for all exothermic reaction?

• A catalyst is needed for the reaction to take place.

• Light is absorbed during the reaction.

• The products of the reaction have less energy than the reactants.

• They are reactions which require heat to start.

Energy is absorbed during some chemical changes. The energy absorbed is used

• to break the bonds between the atoms.

• to form the bonds between the atoms.

• to expand the size of the substance.

• to vaporise the substance.

In which process is energy released?

• electrolysis of water to form hydrogen oxygen

• forming a hydrogen molecule from two hydrogen atoms

• fractional distillation of crude oil

• photosynthesis

Which statement concerning energy change is false?

• Electrical energy is absorbed during electrolysis.

• Electrical energy is produced by the reaction in a battery.

• Light battery is absorbed during photosynthesis.

• Heat energy is absorbed when sodium reacts with energy.

In a energy profile diagram, the difference between the energy of the products energy of the reactions is equal to the

• activation energy.

• energy associated with bond breaking.

• energy associated with formation.

• enthalphy change of the reaction.