1. Where is chemical energy stored within molecules?

a) In the nucleus of atoms
b) In the bonds between the atoms present in molecules
c) As thermal energy present in the reacting molecules
d) As the kinetic energy present in the reacting molecules

2. What energy change is associated with breaking covalent bonds?

a) An exothermic reaction- energy is released
b) An endothermic reaction- energy is absorbed

3. What energy changes is associated with the formation of covalent bonds?

a) Energy is released
b) Energy is absorbed
c) No energy change occurs
d) Energy is both absorbed and released at the same time

4. An exothermic reaction will release energy to the surroundings.

5. What is bond energy or bond enthalpy?

a) The type of bond present in a molecule
b) A measure of how covalent a bond is
c) The energy needed to break 1 mole of bonds
d) A measure of how ionic a bond is

6. gas is identified using the pop test.

7. What is the energy required to break covalent bonds in reacting molecules called?

a) Bond energy
b) Thermal or heat energy

8. What symbol is used to represent the enthalpy change that takes place during a chemical reaction?

a) E
b) H
c) ΔH
d) Σ

9. What is the formula for calculating enthalpy change (ΔH)?

a) ΔH = Σ(energy released by bond formation) - Σ(energy required for bond breaking)
b) ΔH = Σ(energy required for bond breaking) + Σ(energy released by bond formation)
c) ΔH = Σ(energy required for bond breaking)/ Σ(energy released by bond formation)
d) ΔH = Σ(energy released by bond formation)/ Σ(energy required for bond breaking)

10. The law of conservation of energy state that can be created or destroyed only changed from one form into another form of energy.