Endothermic processes and reactions

Endothermic processes and reactions

by Otgonkhuu Ragchaasuren

​Endothermic reactions: Heat is absorbed

​1) Photosynthesis: Plants absorb heat energy from sunlight to convert carbon dioxide and water into glucose and oxygen.

​Endothermic reactions: Heat is absorbed

2) Cooking an egg: Heat energy is absorbed from the pan to cook the egg.

Open Ended

What is other examples of endothermic reactions?

• ​During endothermic reactions, heat is taken in from the surroundings. E.g. thermal decomposition.

• On the other hand, exothermic reactions produce heat.  E.g. burning fuels and burning candles.

​EXOTHERMIC AND ENDOTHERMIC REACTIONS

​Entering = Endothermic = taking in heat

Exiting = Exothermic = giving out heat

​Read and answer questions on CB page 74-75

​Quiz time

Multiple Choice

In an endothermic reaction, heat is ...

• taken in

• given out

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

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

• Exothermic
• Endothermic

Multiple Choice

Which letter shows the activation energy

• A

• B

• C

Multiple Choice

In a reaction the energy required to break bonds is less than the energy released when bonds are made. What type of reaction is this?

• Exothermic

• Endothermic

Multiple Choice

Is this showing an endothermic or an exothermic reaction?

• Endothermic

• Exothermic

Multiple Choice

In an exothermic reaction, heat is ...

• taken in or absorbed
• given out or released

Multiple Choice

In an endothermic reaction, heat is ...

• taken in or absorbed
• given out or released 

Multiple Choice

Is photosynthesis an exothermic or endothermic reaction?

• Endothermic
• Exothermic
• Neither

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 Choice

After you mix two substances together, a new substance forms.  This is an example of:
 

•  Physical Change
•  Chemical Change

Multiple Choice

What term is given to a reaction which transfers heat energy to the surroundings?

• Endothermic

• Reversible

• Exothermic

• Exotermic

Multiple Choice

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? 

• The temperature changed 
• It is an endothermic reaction
• It is an exothermic reaction 
• Two of the answers are correct