CM8001

a) Exothermic. Energy is released from the process in the form of heat as the charcoal burns.

b)Endothermic. Energy is absorbed during the process when it changes from liquid to gaseous state.

c) Endothermic. Energy is absorbed during the process when it changes from solid to liquid state.

The bond strengths of reactants should be weaker than that of the products. To have a good exploson, the reaction should be very exothermic. The difference in relative bond strengths in reactants and products should be significantly large and there should be an higher number of bonds in the reactants. In addition, the products needs to be a gas for the volume to expand during an explosion.

Temperature is the measurement of the “hotness”/”coldness”. For example, heat from the fire increases the temperature of water during boiling.
Heat is what you can feel/sense. Heat is what makes water boils.

a)Octane number of 98 means a knocking characteristic of 98% and 2% heptane. This would be that knocking occurs less often.

b)No. The octane rating does not tell whether the fuel contains oxygenates. Further checks with the supplier needs to be done to ascertain the presence of oxygenates.