CM8001

a) Exothermic – Burning releases energy in the form of heat.

b) Endothermic – Water absorbs heat energy before evaporation occurs.

c) Endothermic – Ice absorbs heat energy, this will cause the ice to melt into liquid due to the rise in temperature. This breaks the intermolecular forces of attraction, such as hydrogen bonding and van der waals, between water molecules.

The reactants will have lower bond strength, whereas the products will have higher bond strength, in order for an exothermic reaction to occur.

Heat is energy that flows from a hotter to a colder region, whereas temperature determines the direction of heat flow. Heat is due to the motion of molecules while temperature is a measure of the average speed of the motion.

a) It has similar knocking resistance as octane.

b) The higher the concentration of oxygenates in the fuel, the higher the octane ratings, which will allow the engine to run more smoothly.