Wednesday, June 1, 2011

PROGRAM KECEMERLANGAN SAINS YAYASAN SELANGOR 2011 : CADANGAN JAWAPAN SOALAN KERTAS 2

CADANGAN JAWAPAN SOALAN 7 DAN SOALAN 8 – YAYASAN SELANGOR

Seperti yang Cikgu janjikan, bersam ini cikgu serta cadangan jawapan kepada latihan yang telah Cikgu berikan semasa sesi program kita di Yayasan Selangor tempohari.. Selamat Menjawab dan selamat menyemak jawapan..

1

a

i

L: 455 gram

N: 435 gram



ii

The weight of potometer in condition M is less than condition N



iii

The weight of potometer is getting lesser because water is loss by transpiration


b


Manipulated variables: Condition of the apparatus

Responding variables: Weight of potometer at the end of experiment// Final weight of potometer


c

i

The higher the speed of fan, the lower the final weight of the potometer



ii

Less than 425 (accept any number below 425)

2

a

i

L – 36

N – 88



ii

The color of distillate in fraction 2 is lighter than the distillate in fraction 3

Distillate in fraction 2 is light yellow but in fraction 3 is yellow



iii

The higher the reading of the temperature, the darker the color of the distillate

As the boiling point increases, the color of the fraction become darker


b


Manipulated variable : temperature

Responding variable : distillate colour


c

i

As the boiling point gets higher, more soot is produced because the fraction becomes less combustible

As the boiling point gets higher, more soot is produced because more carbon

As the boiling point gets higher, more soot is produced because less oxygen

Soot produce increase because the boiling point increase



ii

Darker than yellow

brown

1

a

i

The clothes in Condition A dry faster than in Condition B



ii

Time taken for the clothes to dry in condition A is faster because the presence of sunlight/ surrounding temperature



iii

The higher the temperature, the faster the cloth dry// As the temperature high, the cloth dry faster.


b


With heat sources – 10

Without heat sources - 25


c




d


Drop of water on cobalt chloride paper with heat source dry faster compare to without heat source// Vice versa


e


The higher the temperature of surrounding the higher the rate of evaporation




Manipulated V Present of heat source// lamp

Responding V Time taken for the (cobalt

chloride) paper to dry

Constant V Size of cobalt chloride paper// Number of drop of water/ Volume of water drops

2

a


The air pressure in the tyre increase because the temperature increase


b


40 c – 107

60 c –114

80 c – 121

100 c –128


c

i

ii

Manipulated : Temperature

Responding : Air pressure






e

i

93 c (+-)



ii

The higher the temperature the higher the air pressure

When the temperature increase the air pressure increase

3

a

i

Bus B



ii

The passengers in bus B will feel more warm during hot day because the bus is black in color and will absorb more heat






b

i

Black and dull – 75 c

White and shiny – 45 c



ii

Bar chart



iii

Manipulated : color of object

Responding : final temperature

Constant : initial temperature



iv

The darker the color of an object, more heat will absorb



v

The absorption of heat is the final thermometer reading

4

a

i

The size of sugar cube is smaller because the temperature is higer



ii

The higher temperature of water, the smaller the size of sugar cube/

vise versa.

Semakin tinggi suhu air, semakin kecil saiz gula kiub / sebaliknya


b

i

48sec



ii

Manipulated variable : temperature of water / suhu air

Responding variable : time taken to fine sugar dissolve /masa yang diambil untuk gula halus larut


c


The higher temperature of water, the shorter time taken for sugar dissolves. Vice versa.

Semakin tinggi suhu air, semakin singkat masa diambil untuk gula melarut. sebaliknya


d


(37+1sec)


e


The rate of dissolving is the time taken for sugar to dissolve (at different temperature).

Kadar keterlarutan ialah masa yang diambil untuk gula melarut pada suhu yang berbeza.

5

a

i

Set A



Ii

To lower the melting point of the ice cubes



Iii

Mixture of solid and liquid


b

i

0ºC




Manipulated : time

Responding : temperature




Pure water freezes at 0ºC




Pure water: T // distillation

Impure water: S, U, V // filtration, boiling, chlorination

*accept either letters or names

8

a


Q wilted because there is no water

P looked fresh because there is water



i

5.4



iii

The light intensity is the greatest factor that affect the reading of the position of the air bubble



iv

Light/moving air



v

Air movement increase the reading of the position of the air bubble



vi

7.2




The higher the speed of the moving fan, the higher the position of air bubble



vii

The rate of transpiration is the position of the air bubble

8

a

i

The grasshopper in J died but the grasshopper in K is still alive



ii

The grasshopper in J died because there is no air

The grasshopper in K still alive because there is air/oxygen


b

i

11



ii

More than 11


c


The bigger the size of container, the longer the time taken for the candle to extinguish


d


the time taken for the candle to extinguish


e


Less than 5s

0 not accepted


f


Combustion is the the time taken for the candle to extinguish

8

a

i

Work done in situation L is less than work done in situation M



ii

The heavier the bag, the more time taken to lift the bag



iii

Bag in situation L is lighter than in M because the time taken to lift it is shorter


b

i

250



iii

The reading of the spring balance is directly proportional to the mass of the weight

The higher the mass of the weight, the higher the reading of spring balance



iv

Responding : reading of spring balance

Manipulated: mass of the weight


c

i

Work done is time taken to lift the bag



ii

Work done : S, U

No work done : T, W

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