2.4.3 Energy Changes in Reactions

• Endothermic reactions have a positive energy change.


  True
• Order the steps describing energy changes in exothermic reactions:

  1️⃣ Energy is released as heat

  2️⃣ Reactants have higher energy than products

  3️⃣ The energy change is negative
• In endothermic reactions, the products have higher energy than the reactants.

  True
• Activation energy is the minimum energy required for a reaction to occur
• What happens to the energy of the surroundings in an exothermic reaction?

  It increases
• The energy change in exothermic reactions is positive.

  False
• Exothermic reactions have a positive energy change.

  False
• What is the sign of the energy change in an exothermic reaction?

  Negative
• Match the feature with its description in exothermic reactions:

  Energy Change ↔️ Negative (ΔH < 0)

  Heat ↔️ Released to surroundings

  Reactants ↔️ Higher energy level

  Products ↔️ Lower energy level
• The energy change in endothermic reactions is ΔH > 0.


  True
• Enthalpy is the total energy change
• In endothermic reactions, increasing temperature provides more activation energy.
• Exothermic reactions release heat
• What is the sign of ΔH in an exothermic reaction?

  Negative
• What happens to the energy of reactants in an endothermic reaction?

  It decreases
• What is the sign of ΔH in an endothermic reaction?

  Positive
• Endothermic reactions absorb heat from the surroundings
• In endothermic reactions, the reactants have lower energy
• Order the steps of how energy changes in an exothermic reaction:

  1️⃣ Energy is released as heat

  2️⃣ Reactants have higher energy than products

  3️⃣ Energy change is negative
• In exothermic reactions, energy is released as heat
• Endothermic reactions absorb energy in the form of heat
• What is the minimum energy required for a reaction to occur called?

  Activation energy
• How does increasing temperature affect exothermic reactions?

  Increases reaction rate
• What is the key difference between exothermic and endothermic reactions in terms of sustainability?

  Exothermic are self-sustaining
• What happens to energy in an exothermic reaction?

  Energy is released
• Match the reaction type with its energy change:

  Exothermic ↔️ Negative

  Endothermic ↔️ Positive
• In exothermic reactions, heat is released
• Match the reaction type with its correct feature:

  Exothermic ↔️ Heat released

  Endothermic ↔️ Heat absorbed
• Enthalpy can be positive or negative, depending on the reaction type.


  True
• What does a negative energy change in a reaction indicate?

  Exothermic reaction
• What is released to the surroundings in an exothermic reaction?

  Heat
• Which type of reaction has products with higher energy than reactants?

  Endothermic
• The energy change in an exothermic reaction is denoted as ΔH < 0.


  True
• What is the energy change (ΔH) in endothermic reactions?

  Positive
• Where is heat absorbed from in endothermic reactions?

  Surroundings
• The sign of enthalpy is always positive.

  False
• Activation energy is the energy barrier that must be overcome for a reaction to start.


  True