Calculating Energy Changes and Bond Energies in Chemical Reactions

The video tutorial explains the concepts of bond energies, focusing on the energy changes during bond breaking and making. It distinguishes between endothermic and exothermic processes, providing examples of reactions such as hydrogen chloride formation and ammonia decomposition. The tutorial also covers how to calculate the overall energy change in a reaction and interpret reaction profiles.

What happens to the system's energy when a bond is broken?

• The system becomes unstable.

• The system loses energy.

• The system gains energy.

• The system remains unchanged.

How is bond energy typically measured?

• In watts per second

• In calories per mole

• In joules per atom

• In kilojoules per mole

In the reaction between hydrogen and chlorine, what is the overall energy change?

• 679 kilojoules per mole, positive

• 185 kilojoules per mole, negative

• 679 kilojoules per mole, negative

• 185 kilojoules per mole, positive

What does a negative overall energy change indicate about a reaction?

• The reaction is endothermic.

• The reaction is non-spontaneous.

• The reaction is exothermic.

• The reaction is at equilibrium.

What is the energy required to break all bonds in the hydrogen and chlorine reaction?

• 864 kilojoules per mole

• 432 kilojoules per mole

• 243 kilojoules per mole

• 679 kilojoules per mole

What type of bonds are present in a nitrogen molecule?

• Quadruple bonds

• Single bonds

• Triple bonds

• Double bonds

What is the overall energy change for the decomposition of ammonia?

• 2346 kilojoules per mole, positive

• 93 kilojoules per mole, negative

• 2346 kilojoules per mole, negative

• 93 kilojoules per mole, positive