CM8001

(a) Exothermic because it gives off heat to the environment
(b) Endothermic because water absorb heat from the skin to get evaporated
(c) Endothermic because ice absorbs heat to melt into liquid state

The bond strength in the product is significantly greater than that of the reactant. This is because for exothermic reaction to occur, ΔH=|Energy of reactants|-|Energy of products|<0
It is also known that energy is released when bonds are formed in the product and energy is needed to break the bond in the reactant side.

Heat is a consequence of motion at the molecular level while temperature is a measure of average of that motion.
Set up an experiment with a cup of hot and cold water respectively. Place one hand on the hot cup from until no heat can be felt. Then, place the other hand on the cold cup to feel the ‘coldness’. This feeling of coldness is due to the flow of heat from the ‘hot’hand to the cold cup.

(a) Knocking characteristic of 98% isoctane and 2% heptane
(b) Fuel does contain oxygenates as oxygenates increases the octane rating of the premium gasoline.