CM8001

A . Exothermic , Burning of coal results in releasing energy
B. Endothermic , Water molecules must absorb heat from the surrounding to evaporate , hence causes us to feel cool when water evaporates from our skin.
C. Endothermic , By absorbing heat from the atmosphere to melt. When ice melts at room temperature , it absorbs energy from the surroundings air but not at the Arctic where temperature is less than 0 degrees.

When relative bond strengths of the reactants are less than the relative bond strengths of the products , it would cause the net energy to be more than 0. Exothermic reactions releases heat whereby the bond difference must be tremendous and huge such that ab explosion would occur.
The greater the bond energy difference , the stronger the explosion where if the energy difference is negative , the explosion would be stronger.

In a cold bathroom , running hot water the bath temperature is at 42 degrees. Tthis causes the whole bathroom to be humid and steamed up. This is illustrated as heat.

However in a cold bathroom , where a beaker of water would just be boiled at 100 degrees would be denoted as temperature.

Heat is transfer of energy while Temperature is measuring how fast the particles in a substance are moving.
Hence by touching a hot cup of water , we would feel the heat on to our finger tips . However the temperature cannot be felt and changes.

a) 98% isooctane and 2% n- heptane. This gasoline has a high resistance to knocking. The higher the octane rating, the higher the resistance to knocking.

b) It does not tell us if the fuel contains oxygenates.