F2 IS QZ 02 anwers

Marks: =       /19 =    %

1st Term QZ 02 Submission date：_____________ Name：______________________ Class & no.：2 _________(     )

7.1AB

Word Translation (7 marks)

i    Write down the English terms of the following Chinese terms:

	Chinese term	English term
1	燃燒中的木條	Burning splint
2	帶星火的木條	Glowing splint
3	碳酸氫鹽指示劑	Hydrogencarbonate indicator
4	石灰水	Lime water
5	氯化鈷試紙	Cobalt chloride paper

Fill in the Blanks (8 marks)

1      Oxygen can be tested by burning splint which burns more brightly in oxygen.

Oxygen can also relight a glowing splint.

2      We can use lime water to test for carbon dioxide. Its colour changes from colourless to

milky. We can also use hydrogencarbonate indicator to test for it.

Its colour changes from red to yellow in carbon dioxide.

3      Water can turn dry cobalt chloride paper from blue to pink.

Multiple Choice (4 marks)

Circle the letter of the best answer for each question.

1.       Which of the following does NOT involve the use of a noble gas?                    B

A. Making balloons that can float in air

B. Making soft drinks

C. Making neon lights

D. Making light bulbs

2.       Which of the following shows the correct percentages of different gases in air?               

	Carbon dioxide	Nitrogen	Oxygen	Water vapour
A.	78 %	21 %	Variable	0.03 %
B.	0.03 %	78 %	21 %	Variable
C.	Variable	0.03 %	78 %	21 %
D.	21 %	Variable	0.03 %	78 %

 3.      Which of the following are correct descriptions about air?

(I)        Air is present in all empty spaces.

(II)      Air is basically a mixture of gases.

(III)     Air contains very tiny liquid droplets and solid particles.

A.   (I) and (II) only                                              B.    (I) and (III) only

C.   (II) and (III) only                                           D.    (I), (II) and (III)

  

4.    The diagram below shows a self-made humidity indicator. What are the colours of the cobalt chloride paper in different weather conditions?

		Weather conditions
		Dry	Wet
Colour	A. B. C. D.	pink pink blue blue	pink blue blue pink

Challenging Questions (Bonus 3 marks)

You are provided with 3 jars of gases without correct labels. They are oxygen, carbon dioxide and nitrogen. How can you identify nitrogen from the other gases?

We can test the gases with glowing splint first. If the glowing splint relights, the gas should be oxygen (1).

Next, we test the remaining gases with hydrogencarbonate indicator. If the indicator turns yellow, the gas should be carbon dioxide (1).

The remaining gas which does not relight oxygen and change the colour of the indicator should be nitrogen (1).