Oxford Mastering Science 2A chapter 7 answer

Mastering Science Answers to Workbook 2A

Unit 7

Unit 7

Livin ving things and air

A Sectional Exercise 7.1 7.1 Gase Gases s in the the air air I

(1 m each)

True or fals falsee que quest stio ions ns (p.1 (p.1))

1

F

2

F

3

T

4

T

5

F

6

T (2 m each)

II Fill Fill in in the the blan blanks ks (p. (p.1) 1) 1

atmosphere

2

noble gas

3

glowing, oxygen

4

milky

5

carbon dioxide, higher (1 m each)

III Multiple-hoie questions (p.2) 1

D

2

B

3

C

4

D

5

D

6

B

I! "ue "uesti stions ons (p. (p.4) 4) 1

a b

as B is oxygen

(1 m)

beca!se it relights a glowing splint"

(1 m)

as # t!rns lime water milky" $t is carbon dioxide"

(1 m)

The gas remains is gas C which does not relight a glowing splint and does



not t!rn lime water milky"

(1 m)

as C is nitrogen"

(1 m)

#

(1 m)

© Oxford University Press 2011

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1

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2

Unit 7

$as in the air %itrogen &xygen Carbon dioxide /ater 0apo!r %oble gases &ther gases

%reathe# air * 1+* ("- m) '* ("- m) at!rated "3* ariable

&nbreathe# air * 21* ("- m) ".* ("- m) ariable "3* ariable

a

b

%eon" (&r other reasonable answers")



%reathe# air

&nbreathe# air

#

Test 'ith Test 'ith a burnin h#roenarbonate splint in#iator The indicator changes 4rom The b!rning splint b!rns red to yellow" (1 m) 4or a while and then goes o!t" (1 m) The indicator remains red" The b!rning splint b!rns 4or (1 m) a shorter time than it does in !nbreathed air" (1 m)

Breathe, dry cobalt chloride, bl!e, pink


(1 m)



2



(' m)


Unit 7

7.2 Air and burning I

(1 m each)

True or false questions (p.6)

1

T

2

T

3

F

4

F

5

F (2 m each)

II Fill in the blanks (p.6) 1

&xygen, temperat!re, oxygen

2

Carbon dioxide, water, chemical, heat, light

3

F!el, oxygen, high temperat!re, triangle

4

oxygen

5

oxygen




3




Unit 7

(1 m each)

III Multiple-hoie questions (p.*) 1

C

2

B

3

B

4

B

5

D

I! "uestions (p.+) 1

a

&xygen inside the 5ar is !sed !p when the pean!t b!rns"

(1 m)

b

The dry cobalt chloride paper changes 4rom bl!e to pink"

(1 m)

This shows that water is prod!ced when 4ood is b!rnt in air"

(1 m)

The indicator changes 4rom red to yellow"

(1 m)

Carbon dioxide is prod!ced when 4ood is b!rnt in air"

(1 m)

 #

4ood 6 oxygen


high temperat!re

carbon dioxide 6 water 6 heat energy 6 light energy

    →



4



(2 m)



Unit 7

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5

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6

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7

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8

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9

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1

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11 



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12

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13

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Unit 7

( © Oxford University Press 2011

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14

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Unit 7

(' m)

2

a

b

#7 Do not place the heater near 4lammable materials"

(1 m)

B7 Do not o0erload sockets"

(1 m)

C7 8eep 4lammable materials away 4rom sto0es"

(1 m)

D7 Do not lea0e yo!r cooking !nattended"

(1 m)


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15

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Unit 7

7.3 !o" hu#ans obtain energ$ I

(1 m each)

True or false questions (p.1,)

1

F

2

T

3

T (1 m each)

II Multiple-hoie questions (p.1,) 1

B

2

C

III "uestion (p.11) a

Foo#

Mass of foo# ()

!olue of 'ater use# (3)

ise in 'ater teperature (/0)

%!ts Bacon Bread :i;;a

"" "3 1"1

2 2 2 2

12 3 22

ise in 'ater teperature per ra of foo# (/0) . (1 m) ' (1 m) 1 (1 m) 2 (1 m)

b

Bacon"

(1 m)



Bread"

(1 m)

#

9se the same mass o4 4ood"

(1 m)

Then, we need not calc!late the rise in water temperat!re per gram o4 4ood" (1 m) e

There may be heat loss to the s!rro!ndings when the b!rning 4ood is being mo0ed to the boiling t!be" (&r other reasonable answers")

(1 m)

7.4 !o" green %lants obtain energ$ I

(1 m each)





16




1

F

2

T

3

F

4

F


Unit 7

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17




Unit 7

(2 m each)


destarching

2

prod!cers (1 m each)


D

2

C

3

#

4

B

5

C

6

D

I! "uestions (p.14) 1


(+ m)



18




2

Unit 7

a

The need 4or light in photosynthesis"

(1 m)

b

tarch"

(1 m)

1 2 3 4

teps Boil the lea4 in water"

urpose Destroy the o4 the cell membranes lea4 cells" (1 m)

oak the lea4 in hot alcohol" /ash the lea4 in hot water" #dd iodine sol!tion to the lea4"



=ea4 >

=ea4 ?

#




19




e

f

Unit 7

The part o4 the lea4 co0ered by the al!mini!m 4oil cannot carry o!t photosynthesis witho!t light"

(1 m)

The iodine sol!tion remains brown since no starch is prod!ced"

(1 m)

Both lea4 > and lea4 ? t!rn bl!e@black"

(1 m)

This is beca!se both lea0es ha0e carried o!t photosynthesis and prod!ced 3

starch be4ore the in0estigation"

(1 m)

a

C"

(1 m)

b

C ➝ B ➝ D ➝ #

(2 m)

7.5 Gaseous exchange in ani#als and %lants I

(1 m each)

True or false questions (p.1*)

1

T

2

F

3

F

4

F

5

T

6

F (2 m each)

II Fill in the blanks (p.1*) 1

2

respiration, Anergy

3

gaseo!s exchange, air sacs (1 m each)

III Multiple-hoie questions (p.1+) 1

D




2




2

#

3

C

4

B

5

C

6

B

*

#

Unit 7

I! "uestions (p.2,) 1

2

a

contracts, o!twards and !pwards, contracts, increase, lower

(- m)

b

$t protects the l!ngs"

(1 m)



i

There are many capillaries s!rro!nding the air sacsin the l!ngs"

(1 m)

ii

The air sacs in the l!ngs are 4illed with air"

(1 m)

a

#ir sac"

(1 m)

b

Carbon dioxide"

(1 m)



&xygen"

(1 m)

#

For carrying o!t respiration in body cells"

(1 m)

3

The part in balloon-bell ar o#el lass t!be ?@piece
The part it represents in huan bo# Trachea (1 m) Bronchi (1 m) Diaphragm (1 m)

a

(2 m) b © Oxford University Press 2011

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21

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Unit 7



odel #"

(1 m)

#

p!lled down, increases, lower, into

(' m)

4

0onentration of arbon #ioi#e 0olour of h#roenarbona te in#iator

E ".* (1 m) ?ellow

 ".*

G ".* (1 m)

:!rple (1 m)

a

b

i

T!be #"

(1 m)

ii

T!be B"

(1 m)

Tube

# B

0olour of h#roenarbonate in#iator t the beinnin fter t'o hours


#

i

e sho!ld add a t!be which is not wrapped and with no lea4"

(1 m)

This can make s!re that the colo!r change o4 the indicator in t!be # is ii

ca!sed by the lea4 which takes in carbon dioxide !nder light"

(1 m)

e sho!ld add a t!be which is wrapped b!t with no lea4"

(1 m)

This can make s!re that the colo!r change o4 the indicator in t!be B is © Oxford University Press 2011

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22

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Unit 7

ca!sed by the lea4 which gi0es o!t carbon dioxide in the dark" 5

a b

(1 m)

>7 photosynthesis

(1 m)

?7 respiration

(1 m)

=arge amo!nts o4 4ossil 4!els are b!rnt to meet the increasing energy needs"  =arge areas o4 4orest are cleared to obtain timber or land" (&r other



reasonable answers")

(1 m)

lobal warming"

(1 m)

7.6 Air %ollution and s#o&ing I

(1 m each)


1

T

2

F

3

F

4

T

5

F




23




Unit 7

(2 m each)


poll!tants, air

2

#ir :oll!tion $ndex, 4i0e, air H!ality monitoring

3

%icotine

4

:assi0e (1 m each)


B

2

#

3

C

4

D (- m)

I! Mathin (p.26) a iii

b i0, 0i

 ii, 0ii

# i, 0i

e 0

! "uestion (p.26)

l!ng cancer, greater, greater

(. m)

' (nit Exercise I

(1 m each)

True or false questions (p.2*)

1

F

2

F

3

F

4

F

5

T

6

F

*

F

+

T




24




Unit 7

(1 m each)

II Multiple-hoie questions (p.2*) 1

B

2

B

3

B

4

#

5

#

6

C

*

C

+

D

7

C

1,

B

11

D

III "uestions (p.31) 1

a

To absorb carbon dioxide in !nbreathed air"

(1 m)

This can make s!re any carbon dioxide tested is gi0en o!t by the mo!se

2

only"

(1 m)

b

$t changes 4rom red to yellow"

(1 m)



Breathed air 4rom the mo!se contains carbon dioxide"

(1 m)

#

$t t!rns milky"

(1 m)

e

The dry cobalt chloride paper changes 4rom bl!e to pink"

(1 m)

f

/ater"

(1 m)

a

The oxygen inside the 5ar is !sed !p when the candle b!rns"

(1 m)

b

The candle will b!rn 4or a longer period o4 time

(1 m)

beca!se more oxygen is a0ailable in a larger 5ar"

(1 m)

The candle will b!rn 4or a shorter period o4 time

(1 m)

beca!se a bigger wick cons!mes more oxygen d!ring b!rning"

(1 m)

igh temperat!re

(1 m)

and oxygen

(1 m)

b

/ater cond!cts electricity" /e may get an electric shock"

(1 m)

a

The need 4or carbon dioxide in photosynthesis"

(1 m)

b

To ens!re there is no starch in the lea0es be4ore the experiment"  To destarch

 3

4

a

the plant" 

#

(1 m)

To ens!re the carbon dioxide released by the soil micro@organisms d!ring their respiration

(1 m)

will not be !sed by the plant to carry o!t photosynthesis"

(1 m)

iii ➝ ii ➝ i ➝ i0

(1 m)


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25

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5

Unit 7

e

=ea4 #"

(1 m)

a

Tree ➝ gira44e ➝ lion

(1 m)

b

i

Cons!mer"

(1 m)

ii

:rod!cer"

(1 m)

iii Cons!mer" 

(1 m)

Chemical energy stored in the lea0es on the trees is trans4erred to the gira44es

(1 m)

and then to the lion thro!gh 4eeding"

(1 m)

6

Tube

# B C

0olour of the h#roenarbonate in#iator t the beinnin fter t'o hours
(1 m) (1 m) (1 m)

a

b

i

ii

9nder light, the rate o4 photosynthesis o4 the water plant is higher than that o4 respiration"

(1 m)

There is a net !ptake o4 carbon dioxide 4rom the sol!tion"

(1 m)

The pond snails carry o!t respiration and gi0e o!t carbon dioxide" (1 m)

iii $n the dark, the water plant stops taking in carbon dioxide 4or

photosynthesis"

(1 m)

Both the water plant and the snails carry o!t respiration and gi0e o!t carbon dioxide"

(1 m)

I! ea#in oprehension (p.36) a

$t re4lects the amo!nt o4 carbon dioxide prod!ced by h!man acti0ities"

b

This can red!ce the amo!nt o4 carbon dioxide released to the atmosphere, (1 m) th!s helping combat climate changes d!e to global warming"



i

(1 m)

witch o44 the appliances when not !sing them" (&r other reasonable answers")

ii

(1 m)

(1 m)

9se p!blic transport instead o4 dri0ing pri0ate cars" (&r other reasonable answers")

(1 m)

iii B!y things that are necessary only"  Bring o!r own shopping bags" © Oxford University Press 2011

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26

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Unit 7

(#ny oneI or other reasonable answers")




27



(1 m)


Unit 7

)

!igher *rder +hin&ing ,uestions (p.3*)

1

a

D"

(1 m)

b

BD"

(1 m)



The intercostal m!scles relax"

(1 m)

This allows the ribs to mo0e downwards and inwards"

(1 m)

#t the same time, the diaphragm relaxes and becomes dome@shaped"

(1 m)

There4ore, the 0ol!me o4 the chest ca0ity decreases"

(1 m) (1 m)

#

2

a b 

%icotine"

(1 m)

$t ca!ses addiction to cigarette smoking"

(1 m)

Tar"

(1 m)

$t ca!ses throat and l!ng cancers"

(1 m)

/hen the lining o4 the bronchiole is irritated by tar,

(1 m)

the lining becomes swollen"

(1 m)

$n addition, too m!ch m!c!s is prod!ced"

(1 m)

These narrow the air passage,

(1 m)

th!s red!cing the amo!nt o4 air reaching and lea0ing the air sacs"

(1 m)


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28

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Oxford Mastering Science 2A chapter 7 answer

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