1a) Heat is released when the charcoal burns hence the process is exothermic.
1b) Heat is taken in by the water molecule to change its state to a gaseous form, thus it is an endothermic process
1c) Heat is taken into the ice to melt into water.

Heat is released when bonds are formed and heat is absorbed when bonds are broken. For exothermic reactions, heat is released.Thus, the heat released by the overall reaction must be more than the heat needed to break the bonds for it to become an exothermic reaction.When the bond strength of the product is high, the stability of the products increases and so does the yield. A good explosion will require the very rapid release of heat energy in a very short time, coupled with an expansion of mass rapidly as well.

My friend, heat is the energy that flows from a hotter object to a colder object. It is the consequence of motion at the molecular level. Temperature is a measure of the average speed of the motion, a measurement of how much heat is there by an integer. Like a hot cup of coffee cooling down on the table, heat from the coffee is transferred to the surrounding. The temperature gradually averages with the coffee.

a) Octane rating of 98 means a knocking characteristic of 98% iso-octane and 2% heptane. The rating often measures the ability of the gasoline to burn smoothly without knocking.
b) The higher the octane rating the higher the possibility that it contains oxygenates, it does not provide a definite answer to whether oxygenates are present but a probability.