Energy Changes

Unit 5: Energy Changes

By the end of the lesson, students should be able to:

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1.  Understand the exothermic and endothermic process

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2. Discuss the process that involves exothermic and endothermic processes.

Burning / Combustion

• chemical reaction

• a substance (fuel) combines with oxygen

• heat energy is given out (released)

• often a fast reaction

Oxidation reaction

• any reaction where a substance combined with oxygen

• formed an oxide

• combustion

• rusting

Exothermic reactions

• heat energy is given out

• temperature increases

• reactions of metals with water

• reactions of metals with acid

Endothermic

Multiple Choice

Which one of them is not a fossil fuel?

• Coal

• Water

• Gas

• Oil

Multiple Select

When fuel burns, it gives us____ and ____ energy

Choose all that apply

• Electrical

• Heat

• Light

• Electromagnetic

Multiple Choice

In an exothermic reaction, heat is ...

• taken in

• given out

Multiple Choice

Which of the following process is exothermic?

• Candle wax melting

• A puddle evaporating

• Dry ice (solid carbon dioxide) subliming to form gaseous carbon dioxide

• Water freezing to form ice

Multiple Choice

In an endothermic reaction, heat is ,,,

• taken in

• given out

Multiple Choice

Have you ever eaten sherbet sweets candy? They fizz in your mouth and your tongue feels cold. Why do you think that is?

• It is an exothermic reaction

• It is an endothermic reaction

• It is made of ice

• It is dissolving your mouth

Multiple Select

A student mixed two chemicals to allow them to react. The temperature before the reaction was 25 ° C. The temperature after the reaction was 18° C. Which of the following is true?

• Temperature decreases

• It is an endothermic reaction

• It is an exothermic reaction

• Temperature increases

Multiple Choice

During an endothermic reaction in a beaker if we are part of the surroundings and touched the beaker, it would feel _______.

• Warm

• Cold

Multiple Choice

Is the combustion of gasoline endothermic or exothermic?

• Endothermic

• Exothermic

Multiple Choice

In an endothermic reaction the system is releasing energy.

• True

• False

Multiple Choice

When iron nails get rusty, heat is released. What process is this?

• Exothermic

• Endothermic

Multiple Choice

If a chemical reaction is EXOTHERMIC, the temperature would....

• Stay the same

• Increase

• Decrease

Multiple Choice

What type of reaction occurs in a hand warmer

• exothermic

• endothermic