The word equation for photosynthesis is: water + carbon dioxide → glucose + oxygen The word equation for respiration is: glucose + oxygen → carbon dioxide + water Use your scientific knowledge to explain which process is exothermic and which is endothermic.

The word equation for photosynthesis and respiration is given from this we can conclude photosynthesis is an endothermic process. This means it cannot occur without energy (from the Sun). The light required is absorbed by a green pigment called chlorophyll in the leaves. water + carbon dioxide → glucose + oxygen Respiration is a series of exothermic reactions that occur in the mitochondria of living cells to release energy from food molecules. glucose + oxygen → carbon dioxide + water

E M B I B E

Cambridge Lower Secondary Science Stage 9: Workbook>Chapter 8 - Energy Transfers in Chemistry>Exercise 2

Aiden Gill, Heidi Foxford and, Dorothy Warren Solutions for Chapter: Energy Transfers in Chemistry, Exercise 2: Exercise 2

Author:Aiden Gill, Heidi Foxford & Dorothy Warren

Aiden Gill Science Solutions for Exercise - Aiden Gill, Heidi Foxford and, Dorothy Warren Solutions for Chapter: Energy Transfers in Chemistry, Exercise 2: Exercise 2

Attempt the practice questions on Chapter 8: Energy Transfers in Chemistry, Exercise 2: Exercise 2 with hints and solutions to strengthen your understanding. Cambridge Lower Secondary Science Stage 9: Workbook solutions are prepared by Experienced Embibe Experts.

Questions from Aiden Gill, Heidi Foxford and, Dorothy Warren Solutions for Chapter: Energy Transfers in Chemistry, Exercise 2: Exercise 2 with Hints & Solutions

MEDIUM

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Workbook>Chapter 8 - Energy Transfers in Chemistry>Exercise 2>Q 1

Which of the following is an example of an endothermic process?

MEDIUM

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Workbook>Chapter 8 - Energy Transfers in Chemistry>Exercise 2>Q 2

Complete the sentences that follow by choosing words from this list.

(increase, decrease, endothermic, light, exothermic, combustion, heat, energy)

______ processes transfer energy to the surroundings - often as heat- and cause a temperature _____.

_____ processes transfer energy from the surroundings, often as _____.

HARD

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Workbook>Chapter 8 - Energy Transfers in Chemistry>Exercise 2>Q 3

Priya and Lily are investigating the energy changes that take place during dissolving.

They follow this method:

• Pour $10 {cm}^{3}$ of water into a boiling tube.

• Record the temperature of the water. Add $0.5 g$ of ammonium chloride and stir.

• Record the temperature when the ammonium chloride has dissolved.

Here are their results:
Start temperature in °C $20.0$
The final temperature in $° C$ $18.5$

Priya thinks that if they repeat the experiment using $9 {cm}^{3}$ water the temperature change will stay the same, but Lily thinks it will decrease further.

Explain why Lily is correct.

HARD

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Workbook>Chapter 8 - Energy Transfers in Chemistry>Exercise 2>Q 4

The word equation for photosynthesis is:

water + carbon dioxide $\to$ glucose + oxygen

The word equation for respiration is:

glucose + oxygen $\to$ carbon dioxide + water

Use your scientific knowledge to explain which process is exothermic and which is endothermic.