1. From personal experience, state whether these processes are endothermic or exothermic. Give a reason for each.

A. A charcoal briquette burns

Exothermic – Heat released to the surroundings

b. Water evaporates from your skin.

Endothermic -The human skin loses heat and decreases in temperature

c. Ice melts

Endothermic – Heat is absorbed from the surroundings

 

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2. For a good explosion, the difference between the energy levels of bond formation and form breaking should be large. Bond strength of reactants should be weaker than bond strength of products.

 

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3. How might you explain the difference between temperature and heat to a friend? Use some practical, everyday examples.

Temperature is the parameter that determines the direction of heat flow.

When boiling water, the temperature is the measure of hotness or coldness. While heat is what we feel when we get in contact with the boiling water.

 

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4. A premium gasoline available at most stations has an octane rating of 98. What does that tell you about:

a. The knocking characteristics of this gasoline?

98% isooctane, 2% heptane

b. whether the fuel contains oxygenates?

It does not contain oxygenates. the fuel octane rating is 98, and a fuel that contains oxygenates would be above 100 for the rating.