Which of the following statements correctly describes an exothermic reaction?

In an endothermic reaction, which of the following occurs?

• Bond making releases more energy than bond breaking.

• Bond breaking absorbs more energy than bond making releases.

• Bond making absorbs more energy than bond breaking releases.

• Bond breaking releases more energy than bond making absorbs.

What is the unit of molar enthalpy change?

• kJ

Which of the following is a characteristic of an energy profile diagram for an exothermic reaction?

• The products are at a higher energy level than the reactants.

• The reactants are at a higher energy level than the products.

• The energy level of the reactants and products is the same.

• The activation energy is zero.

Which of the following is true for the incomplete combustion of a hydrocarbon?

• It produces only carbon dioxide and water.

• It produces carbon monoxide, carbon, and water.

• It requires more oxygen than complete combustion.

• It is an endothermic process.

What is the enthalpy change for a reaction if the energy required to break bonds is 500 kJ and the energy released in making bonds is 800 kJ?

• It is the energy change per mole of substance.

• It is the energy change per gram of mixture.

• It is the total energy change for the reaction.

• It is the energy change per litre of solution.

In an energy profile diagram, what does the peak of the curve represent?

• The energy of the reactants.

• The energy of the products.

• The activation energy.

• The enthalpy change of the reaction.

Which of the following is a correct statement about bond making and bond breaking in chemical reactions?

• Bond making is an endothermic process.

• Bond breaking is an exothermic process.

• Bond making is an exothermic process.

• Bond breaking is an endothermic process.