5.1 Exothermic and endothermic reactions

• Endothermic reactions cause the temperature of the surroundings to increase.

  False
• Endothermic reactions cause the temperature of the surroundings to decrease
• During an endothermic reaction, energy is released to the surroundings.

  False
• Exothermic reactions always increase the temperature of their surroundings.


  True
• What form of energy is released in exothermic reactions?

  Heat
• Arrange the following processes in the order of energy transfer and temperature change in an exothermic reaction:

  1️⃣ Energy is released to the surroundings

  2️⃣ Temperature of surroundings increases
• Exothermic reactions cause the temperature of the surroundings to decrease.

  False
• The burning of fuels is an example of an exothermic reaction.


  True
• The melting of ice is an endothermic reaction.

  True
• Exothermic reactions increase the temperature of the surroundings.


  True
• What is an exothermic reaction?

  Releases energy in heat
• Match the type of reaction with its property:

  Exothermic ↔️ Energy is released

  Endothermic ↔️ Energy is absorbed
• Arrange the steps involved in a chemical reaction to show energy changes in exothermic and endothermic reactions:

  1️⃣ Reactants combine

  2️⃣ Energy is either absorbed or released

  3️⃣ Products are formed

  4️⃣ Temperature of surroundings changes
• In endothermic reactions, energy is absorbed from the surroundings
• During an exothermic reaction, energy is transferred from the reaction to the surroundings
• In endothermic reactions, energy is absorbed from the surroundings.
• Which reaction is an example of an exothermic reaction?

  Respiration
• What is the key difference between endothermic and exothermic reactions in terms of energy input?

  Endothermic requires energy input
• What is an example of an endothermic reaction?

  Photosynthesis
• Why is photosynthesis considered an endothermic reaction?

  It absorbs energy
• In exothermic reactions, energy is released in the form of heat
• Give an example of an exothermic reaction.

  Burning of fuels
• What happens to the surroundings during an endothermic reaction?

  Temperature decreases
• Which process is an example of an endothermic reaction?

  Melting of ice
• Why does the temperature decrease during an endothermic reaction?

  Energy is absorbed
• Endothermic reactions cause the temperature of the surroundings to increase.

  False
• In exothermic reactions, energy is released from the system to the surroundings.
• In endothermic reactions, the temperature of the surroundings decreases.
• In exothermic reactions, energy is released to the surroundings.
• In endothermic reactions, energy is absorbed from the surroundings.