CM8001

a. Exothermic – heat is released.
b. Endothermic – heat is absorbed and the skin cools down.
c. Endothermic – Drink is cooled.

Bond strengths of reactants are weaker than bond strengths of product. The bond strengths of reactants are weaker as bonds can break easily, thus absorbing less energy, while the bond strength of the products are stronger so a lot more energy is released during bond forming. Thus the reaction is highly exothermic.

Heat is a consequence of motion at the molecular level.
Temperature is the measure of an average speed of the motion.
Heat: Placing a cup of hot tea on the table and the hot tea becomes colder (transfer of heat to surroundings)
Temperature: When you cook food, the temperature increases.

a) Octane rating is a measure of a fuel’s ability to resist knocking. The higher the octane rating, the higher its resistance to knocking. An octane rating of 98 means a knocking characteristic of 98% isooctane and 2% heptane.

b) Yes. A high octane rating means that it is likely to contain oxygenates.