CM8001

a) Exothermic, Heat energy is released from the charcoal to cook food thus when standing near charcoal people will feel hot.
b) Endothermic, Water absorbs heat from the skin as it evaporates and thus giving a cool feeling.
c) Endothermic, heat energy is absorbed to break the intermolecular forces as rigid ice becomes slippery liquid.

Since chemical explosions are highly exothermic, Reactants should have a low bond strength and products should have high bond strength. This would lead to negative H and thus an exothermic reaction.

Heat is the amount of energy in a system –> SI units Joules
Temperature is the measure of average molecular movements in a system –> SI unit Kelvin.

Everyday examples,
For temperature, just show your friend the thermometer.
For heat ask him/her to touch a stove.

98 Octane number tells us that it has a knocking characteristic of 98% isooctane and 2% heptane.

It can be assumed that octane number below 100 has no oxygenates as oxygenates are additives used to increase the overall rating of the gasoline.