Chp 9.3 : Indicators

Question 1

pH of acids and the colours of acid

Answer 1

1-6
Red or orange

Question 2

pH of alkali and the colours of alkali?

Answer 2

8-14
Blue or purple

Question 3

What is an indicator?

Answer 3

Indicator is a substance that has different colours in acid and alkaline solution.

Question 4

How does most plants grow best in what condition?

Answer 4

They grow best in neutral or slightly alkaline conditions.

Question 5

How can too acidic be treated?

Answer 5

Alkaline such as quicklime (calcium oxide) or slaked lime (calcium hydroxide)

Question 6

What are oxides?

Answer 6

They are compounds and they form when oxygen reacts with metal.

Question 7

What can oxides classified as?

Answer 7

Basic, acidic , neutral or amphoteric

Question 8

Name 3 acidic oxides (non-metal)

Answer 8

1) Carbon dioxide (CO2)
2) Nitrogen dioxide (NO2)
3) Sulfur dioxide (SO2)

Question 9

Name 3 neutral oxides (non-metal)

Answer 9

1) Water (H2O)
2) Carbon monoxide (CO)
3)Nitrogen monoxide (NO)

Question 10

Name 5 basic oxides ( metal )

Answer 10

1) sodium oxide
2) Potassium oxide
3) Calcium oxide
4) magnesium oxide
5) Copper (II) oxide