CM8001

a. Exothermic. When charcoal is burnt, it feels warm and hence we can assume that heat is released.
b. Endothermic. When water evaporates from our skin, it feels cool because water absorbs heat from our skin to evaporate.
c.Endothermic. When ice melts, it changes to liquid form (water). In order for it to melt, it needs to take in heat from surroundings. Hence, the process is endothermic.

For a good explosion, the chemical explosion needs to release a lot of energy and hence, it is a highly exothermic reaction. The net bond strength is a very large negative number. Hence bond strengths of products must be much lower than bond strengths of reactants. Gases are able to produce high energy release due to fast variation in volume change.

Temperature: The number and type of energy.
Heat: Amount of energy measured in units.
E.g. Comparing a small cup of water with a big cup of water, both have the same temperature. However, the big cup of water has more energy due to a larger volume.

a. 98% isooctane and 2% n-heptane
b. Insufficient information is provided to deduce if the fuel contains oxygenates. Octane rating only gives info on quality of fuel.