Workbook Answers: Ch11

Sectional Exercise
Section 11.1
A. Concept checking p.61
1. False
2. True
3. True
4. False
5. True

B. Questions p.61
1. (a) sight; eyes
(b) hearing; ears
(c) heat; skin
(d) smell; nose
(e) taste; tongue
(f) touch; skin
2. (a) Eyes, tongue or nose
(b) Nose or skin
(c) Tongue
(d) Skin
(e) Ears
(f) Nose or tongue

Section 11.2
A. Concept checking p.62
1. False
2. True
3. False
4. False
5. False

B. Multiple choice p.63
1. C
2. A
3. D
4. D

C. Matching p.64
(a) i, iv
(b) ii, iii
(c) ii, iv
(d) i, iii

D. Questions p.65
1. (a) A : cornea B : iris
D : pupil E : lens
G : retina H : yellow spot
I : blind spot J : optic nerve
(b) (i) A, C , E and F
(ii) G
(iii) E
(c) It protects the eyeball and gives it shape.
2. (a) R
(b) Q
(c) P, R and S

Section 11.3

A. Concept checking p.67

1. True

2. False

3. False

4. False

5. True

B. Matching p.67

(a) Telescope; i, iv

(b) Binoculars; i

(c) Hand lens; ii

(d) Light microscope; iii

Section 11.4

A. Multiple choice p.68

1. B

2. D

3. A

4. A

5. D

B. Fill in the blanks p.70

(a) (i) near

(ii) thin

(iii) short

(iv) convex

(b) (i) certain colours

(ii) cones

(c) (i) cataracts

(ii) artificial lens

(d) (i) distant

(ii) thick

(iii) long

(iv) concave

Integrated Exercise

A. Multiple choice p.84

1. D

2. C

3. D

4. B

5. C

6. A

7. D

8. C

B. Fill in the blanks p.90

1. (a) sight

(b) light receptors

(c) retina

(d) optic nerve

(e) blind spot

C. Questions p.91

1. (a) Stimulus/stimuli: Temperature of water

Sense organ(s): Skin

Sense(s): Heat and cold

(b) Stimulus/stimuli: Chemicals / citric acid / lemon juice in the drink

Sense organ(s): Tongue

Sense(s): Taste

(c) Stimulus/stimuli: Chemicals / LPG / town gas in air

Sense organ(s): Nose

Sense(s): Smell

(d) Stimulus/stimuli: Light and sound / thunder and lightning

Sense organ(s): Eyes and ears

Sense(s): Sight and hearing

2. (a) P : lens; Q : cornea; R : iris; S : optic nerve

(b) (i) P , Q and T

(ii) This allows light to pass through.

(c) Retina. It contains light receptors that can detect light and send signals to the brain.

(d) (i) This point is called the blind spot.

(ii) No, we cannot see the object. The reason is that there are no light receptors on 

                        the blind spot, no signals are produced when the light from an object is focused on it.

Quick Review

A. Sensing the environment p.97

(a) stimuli

(b) receptors

(c) brain

(d) senses

(e) responses

B. Our senses p.97

(b) (i) sound receptors

(ii) cochlea

(c) (i) smell receptors

(ii) nose

(d) (i) taste receptors

(ii) taste bud

(e) skin

Workbook Answers: Ch10 Quick Review

Quick Review
A. The pH scale p.54
(a) hydrochloric acid
(b) orange juice
(c) distilled water
(d) glass cleaner
(e) sodium hydroxide
(f) acidity
(g) neutral
(h) alkalinity

B. Reactions of acids with various substances p.54
(a) (i) iron
(ii) zinc
(iii) magnesium
(iv) Hydrogen
(v) warm
(vi) heat

(b) (i) marble
(ii) limestone
(iii) Carbon dioxide

C. Causes and effects of acid rain p.56
(a) sulphur dioxide
(b) nitrogen oxides
(c) acids
(d) rivers
(e) lakes
(f) acidic
(g) corrode

Workbook Answers: Ch10 Integrated Exercise

Integrated Exercise
A. Concept checking p.45
1. True
2. False
3. True
8. False
9. True
10. False

B. Multiple choice p.45
1. C
2. B
3. B
4. C
5. A
7. A
8. D

C. Questions p.48
1. (a) Solution A: vinegar
Solution B: rainwater
Solution C: soap solution
Solution D: lime water
(b) Its pH value may be between 8.8 and 12.3.

2. (a) Indicators P and T
(b) Indicators Q and R are blue in ammonia.
(c) Indicator Q is yellow in both acids. Indicator S is colourless in both acids.
(d) Indicator P is yellow in ethanoic acid and in sodium hydroxide.
(e) Indicator P is red in a solution with a pH value equal to or less than 2. Indicator T is yellow
                in a solution with a pH value in between 2 and 8. If a solution looks red after adding
                indicator P and yellow after adding indicator T, it means that the solution has a pH value
                of about 2.

3. (a) Red
(b) Concentrated hydrochloric acid gives off an acidic vapour. The acidic vapour dissolves in
                the water in the moist blue litmus paper and turns the litmus paper red.

4. (a) Colourless gas bubbles are given out.
(b) (i) The lime water turns milky.
(ii) The gas released in the reaction is carbon dioxide.
(c) Marble / calcium carbonate / other carbonates

Workbook Answers 10.5

Section 10.5

A. Concept checking     p.34

False

True

True

True

B. Multiple choice          p.34

B

D

D

C

C. Questions                   p.35

1.    (a)     Rainwater that has a pH value lower than 5.6.

       (b)     Sulphur dioxide and nitrogen oxides

       (c)     Calcium carbonate

       (d)     Calcium carbonate in limestone reacts with acid rain. Calcium carbonate dissolves and gives off carbon dioxide in the process.

       (e)     •      Making the water in lakes and rivers so acidic that fish and plants cannot survive.

                 •      Making soil too acidic and thus affecting plant growth.

                 (or other reasonable answers)

2.    A small amount of vinegar was left in the bottle. The water she used to water her plants was therefore acidic. As a result, the soil became too acidic for plant growth and the plants died.

Workbook Answers 10.4

Section 10.4

A. Concept checking      p.31

False

True

True

True

B. Multiple choice           p.31

D

A

C

C

B

C. Matching                    p.32

(a)    ii

(b)    i

(c)    iv

(d)   iii

D. Question                     p.33

(a)    The gas is not hydrogen.

(b)    (i)

    

                (or other reasonable answers)

        (ii)    The gas is carbon dioxide.

(c)    Calcium carbonate

Workbook Answers Ch 10.1 - 10.3

Sectional Exercise
Sections 10.1 & 10.2
A. Concept checking p.25
1. True
2. False
3. False
4. True
5. False
6. True

B. Multiple choice p.25
1. B
2. D
3. B
4. C
5. B
6. A
7. A

C. Fill in the blanks p.27
1. sour
2. opposite
3. (a) bitter
(b) soapy / slippery
4. (a) sodium hydroxide
(b) potassium hydroxide
(c) protective gloves / gloves
5. (a) slow running water / the tap
(b) 10

Section 10.3

A. Multiple choice p.27

1. B

2. D

3. C

4. A

5. A

B. Fill in the blanks p.28

1. (a) blue

(b) red

(c) red

(d) blue

(e) Neutral

2. (a) degree

(b) acidic

(c) neutral

(d) alkaline

C. Questions p.29

1. (a) ii

(b) iv, vii

(c) v, vi

(d) iii

(e) i, viii

2. (a) Its pH value may be 2.5 – 5.

(b) Carbon dioxide is boiled off. There is no / less carbonic acid. The amount of acid in the drink decreases, so the drink becomes less acidic and its pH value increases.

3. (a) Use a piece of pH paper / a pH meter / universal indicator solution to measure its pH value.

(b) Silk Liquid Soap

(c) ABC Liquid Soap

(d) Silk Liquid Soap has a pH value of 5.5, which is the same as the pH value of healthy skin. It is better for our skin. Soap solution has a pH value of 10, which is significantly higher than the pH value of our skin and may irritate / harm our skin.

Integrated Exercise

A. Concept checking p.45

1. True

2. False

3. True

B. Multiple choice p.45

1. C

2. B

3. B

4. C

C. Questions p.48

1. (a) Solution A: vinegar

Solution B: rainwater

Solution C: soap solution

Solution D: lime water

(b) Its pH value may be between 8.8 and 12.3.

2. (a) Indicators P and T

(b) Indicators Q and R are blue in ammonia.

(c) Indicator Q is yellow in both acids. Indicator S is colourless in both acids.

(d) Indicator P is yellow in ethanoic acid and in sodium hydroxide.

(e) Indicator P is red in a solution with a pH value equal to or less than 2. Indicator T is yellow in a solution with a pH value in between 2 and 8. If a solution looks red after adding indicator P and yellow after adding indicator T, it means that the solution has a pH value of about 2.

Ch 9 Workbook Answers

Workbook Answers Chapter 8

Section 8.1 (P.51)

A. Concept checking

1.          False

2.          True

3.          False

4.          True

5.          True

B. Multiple choice

1.     (a)    electrical conductors

(b)    electrical insulators

2.     (a)    closed

        (b)    open

C. Question

1.     (a)    electrical insulator

(b)    electrical conductor

(c)    electrical insulator

(d)   electrical conductor

(e)    electrical insulator

(f)    electrical insulator

(g)    electrical insulator

(h)    electrical conductor

(i)     electrical conductor

2.

3.     (a)    (i)     will not

                (ii)    do not form

        (b)    (i)     will

                (ii)    form a closed circuit

        (c)    (i)     will

                (ii)    the bulb, the dry cells and the wires form a closed circuit

        (d)   (i)     will not

                (ii)    electrical energy in the circuit

4.     No. The wheels of the tram are connected with the power supply through the rails, and the circuit is complete. (or other reasonable answers)

Section 8.2 & 8.3 (P.54)

A. Multiple choice

1.     (a)    ampere

        (b)    volt

2.     free electrons

3.     1.5

4.     (a)    ammeter

        (b)    voltmeter

5.     larger

B. Question

1.     (a)    dry cell

(b)    wire

(c)    free electrons

Section 8.5
A. Multiple choice p.60-61
1. D
2. C
3. B
4. C

B. Question p.61-62
1.
(a) dry cell
(b) battery
(c) bulb
(d) ammeter
(e) voltmeter
(f) resistor
(g) rheostat
(h) switch

Integrated Exercise
A. Concept checking p.79
1. False
2. True
3. False
4. False
5. True
6. True

B. Multiple choice p.80-83

1. B

2. D

3. B

4. C

5. B

6. D

7. D

8. C

9. B

Quick Review
1. Electric current, voltage and resistance p.90
(a) open
(b) closed
(c) voltage
(d) larger
(e) resistance
(f) smaller
(g) current
(h) brighter

2. Ammeter, rheostat and fuse p.90
(a) rheostat
(b) resistance
(g) (electric) current
(h) black
(i) positive

Workbook Answers Ch7 Integrated Exercise

Integrated Exercise
A. Concept checking p.30
1. True
2. True
3. False
4. True
5. True
6. False
7. True
8. False

B. Multiple choice p.30-34
1. C
2. C
3. D
4. D
5. D
6. A
7. C
8. D
9. C
10. B

C. Matching p.35
1. (a) ii, iii, v, vii
(b) i, iv, vi, viii

2. (a) iii, iv
(b) ii, v
(c) i, vi


D. Questions p.36-41

1. (a) (i) oxygen
(ii) Put a glowing splint into the test tube. If it relights, it shows that the gas is oxygen.
(iii) It is used to provide carbon dioxide for the water plant to carry out photosynthesis.

(b) (i) The rate of bubbling increase.
(ii) The rate of photosynthesis increases when the light intensity increases.

2. (a) (i) It remains colourless. It shows that no carbon dioxide is present in the air entering the bell jar.
(ii) It changes from red to yellow. It shows that the mouse releases carbon dioxide.

(b) Sodium hydroxide solution absorbs carbon dioxide from the incoming air. This ensures that the colour change of the indicator in flask C is due to carbon dioxide released from the mouse.

(c) (i) Place the set-up in the dark. (or other reasonable answers)
(ii) Without light, the plant cannot undergo photosynthesis. This ensures that the experimental result is due to respiration of the plant only. (or other reasonable answer)

3. (a) (i) Respiration: food + oxygen ==> carbon dioxide + water energy
(ii) light energy
Photosynthesis: carbon dioxide +water ==========> food +oxygen
chlorophyll
(b) (i) The rate of net oxygen absorption will be negative.
(ii) The rate of net oxygen absorption will be positive.

(c) (i) From 0600 to 1800
(ii) From 1800 to 2400 and 0000 to 0600

E 4. (a) (i) B to C, D to E
(ii) N to P, R to T

(b) The chest volume decreases while the gas pressure inside the chest increases.

(c) (i) The intercostal muscles relax, causing the ribs move downwards and inwards. Hence, the volume inside the chest decreases.
(ii) The diagram moves upwards, thus the volume inside the chest decreases.