Question 1: From personal experience, state whether these processes are endothermic or exothermic. Give a reason for each.
A. Exothermic, gives out heat
B. Endothermic, takes heat in to evaporate
C. Endothermic, takes in heat to melt
Question 2
Chemical explosions are very exothermic reactions. Describe the relative bond strengths in the reactants and products that would make for a good explosion.
Bond breaking that occurs in an reactant would be Endothermic, whereas bond formation that occurs in an reactants would be Exothermic.
To produce a good explosion, the bond strength of the products should be much stronger as compared to the reactants.
y are released.
Question 3:
How might you explain the difference between temperature and heat to a friend? Use some practical, everyday examples?
An object with no heat energy still has a temperature of 0K (Kelvin). Temperature is a measure of heat inside a medium.
Heat is measure of temperature transfer from warm to cold area.
An oven set at 200°C provides heat energy to food to raise its temperature to 200°C
– In a situation of a unfortunate event where a person burn his skins from a cup of hot water, the area of the skin where the hot water touches will experience burning sensation. This is due to the presence of heat / heat content. As heat is a form of energy, it flows from a point of higher temperature to a lower temperature
( If you put your hand into hot water, you will feel hot, this is due to the presence of heat)
*Cold water – lack of heat, feels cold.
Question 4:
A premium gasoline available at most stations has an octane rating of 98. What does that tell you about:
The knocking characteristics of this gasoline?
a) 98% is octane and 2% heptane
Whether the fuel contains oxygenates?
b) might contain premium gasoline and expensive due to addition of oxygenates which are costly. The octane rating is also relatively high so it is possible that it is enhanced.
Might not contains oxygenates usually for gasoline with octane ratings exceeding 100.
Group 7 Topic!
