Problem Explanation:
The task requires you to explain the energy changes in two types of chemical reactions:
exothermic and
endothermic, and to draw the direction of arrows indicating the flow of energy in each case.
#### Key Concepts:
1.
Exothermic Reaction:
- Energy is released during the reaction.
- The products have lower energy than the reactants.
- Heat is given off to the surroundings, often causing a rise in temperature.
2.
Endothermic Reaction:
- Energy is absorbed during the reaction.
- The products have higher energy than the reactants.
- Heat is taken from the surroundings, often causing a drop in temperature.
---
Solution:
#### 1.
Exothermic Reaction
-
Image Description: The image shows a flame, which indicates heat being released.
-
Explanation: In an exothermic reaction, the reactants have more energy than the products. During the reaction, this excess energy is released as heat, light, or other forms of energy. The arrow should point
outward from the system to indicate that energy is being released to the surroundings.
-
Arrow Direction: Draw an arrow pointing outward (away from the flame) to represent the release of energy.
#### 2.
Endothermic Reaction
-
Image Description: The image shows ice cubes melting into water, which indicates absorption of heat.
-
Explanation: In an endothermic reaction, the reactants have less energy than the products. To proceed, the reaction absorbs energy from the surroundings. The arrow should point
inward toward the system to indicate that energy is being absorbed.
-
Arrow Direction: Draw an arrow pointing inward (toward the ice cubes) to represent the absorption of energy.
---
Final Answer:
- For the
Exothermic Reaction (flame):
- Draw an arrow
pointing outward from the flame to indicate energy release.
- For the
Endothermic Reaction (melting ice):
- Draw an arrow
pointing inward toward the ice cubes to indicate energy absorption.
Final Answer Boxed:
$$
\boxed{\text{Exothermic: Arrow pointing outward; Endothermic: Arrow pointing inward}}
$$
Parent Tip: Review the logic above to help your child master the concept of exothermic and endothermic reactions worksheet middle school.
