Quiz 14: WS10.3 Answers

Kowloon Tong School (Secondary Section)

F.2 Integrated Science Quiz 14: WS10.3

Words Translation (10 marks)

	Chinese term	English term
1	指示劑	Indicators
2	天然的	Natural
3	紅色石蕊	Red litmus
4	藍色石慈	Blue litmus
5	中性的	Neutral
6	程度	Degree
7	通用指示劑	Universal indicator
8	pH試紙	pH paper
9	pH值	pH value
10	pH標度	pH scale

Fill in the Blanks (10 marks)

1        An acid-alkali (1)indicator shows different colours in acids and alkalis. It can be used to distinguish acids from alkalis.

2        Some deeply coloured plants show different colours in acids and alkalis. They can be used to make (2)natural acid-alkali indicators.

3        There are two forms of (3)litmus which are red and blue in colours. Both of them are

available in solution and paper form. The blue one can be turned red by (4)acids.

4        Distilled water does not change the colours of the two forms of litmus paper. It is said to be

(5)neutral.

5        We can use (6)universal indicator to show the (7)degree of acidity an alkalinity of a substance. This indicator is available in solution and paper form. Its paper form is called (8)pH paper.

6        We usually measure acidity and alkalinity in terms of (9)pH value.

7        The scale for measuring acidity and alkalinity in terms of pH values is called (10)pH scale.

Challenging Questions (Bonus 3 marks)

Suggest a possible substance which has the following pH value:

(a)    pH 0:        hydrochloric acid

(b)   pH 7:        distilled water

(c)    pH 14:      sodium hydroxide