S1-Acid and Bases

Question 1

What is the chemical formula of Sulfuric acid?

Answer 1

H2 SO4

Question 2

What is the chemical formula of Hydrochloric acid?

Answer 2

HCl

Question 3

What is the chemical formula of Nitric acid?

Answer 3

HNO3

Question 4

What are the 6 properties of acid?

Answer 4

• sour taste
• turn blue litmus paper red
• pH value less than 7
• corrosive
• conduct electricity
• react with metals, carbonates, bases/alkalis

Question 5

What is the word equation for reaction between acid and metal?

Answer 5

acid + metal -> salt + hydrogen

Question 6

How to test for hydrogen gas?

Answer 6

• lighted splint
• ‘pop’ sound
• lighted splint extinguishes

Question 7

Are salts neutral substances?

Answer 7

Yes

Question 8

What does carbonates contain?

Answer 8

metal or ammonium ions

Question 9

What is the word equation for acid + carbonate?

Answer 9

acid + carbonate -> salt + water + carbon dioxide

Question 10

How to test for carbon dioxide?

Answer 10

• limewater ( calcium hydroxide )

- turn chalky/cloudy/milky

Question 11

What is neutralisation reaction?

Answer 11

Acids react with base or alkali to form salt and water

acid + base/alkali -> salt + water

Question 12

Uses of sulfuric acid

Answer 12

• fertilisers
• detergents
• batteries (vehicles)

Question 13

Uses of hydrochloric acid

Answer 13

• removal of rust

- leather processing

Question 14

Uses of ethanoic acid

Answer 14

• vinegar (preserve)

- adhesives

Question 15

Uses of citric acid

Answer 15

• preservative

- flavouring

Question 16

Uses of nitric acid

Answer 16

• production of fertilisers
• explosives
• plastic
• medicinal drug

Question 17

What are bases?

Answer 17

They are compounds formed between metals and oxygen, so they are oxides of metals. They react with acids to produce salt and water only.

Question 18

What is an alkali?

Answer 18

Bases that are soluble in water (hydroxide)

Question 19

What are the 6 properties of alkalis?

Answer 19

• bitter taste
• slippery/ soapy
• turn red litmus paper blue
• corrosive
• conduct electricity
• neutralisation

Question 20

Use of calcium hydroxide / oxide

Answer 20

-neutralise acid in soil

Question 21

Use of aluminium hydroxide

Answer 21

• antacid (ingestion tablet)

- relieve pain in stomach

Question 22

Uses of magnesium hydroxide

Answer 22

• antacid

- toothpaste

Question 23

Uses of sodium hydroxide

Answer 23

• floor, oven cleaner

- soaps and detergents

Question 24

Use of ammonia

Answer 24

-window cleaning solution

Question 25

What is pH scale?

Answer 25

numbered between 0 to 14. pH is a measure of how acidic or alkaline a solution is in water.

Question 26

What are indicators?

Answer 26

They are chemical substances which change colours when they come into contact with acids or alkalis.

Question 27

what are the 4 indicators?

Answer 27

• litmus paper
• phenolphthalein
• methyl orange
• bromophenol blue

Question 28

pH colour when indicators change

9

Answer 28

litmus : 7.0
phenolphthalein : 9.7
methyl orange : 3.7
bromophenol blue : 4.0

Question 29

colour of indicator acid

Answer 29

litmus : red
phenolphthalein : colourless
methyl orange : red
bromophenol blue : yellow

Question 30

colour of indicator in alkalis

Answer 30

litmus : blue
phenolphthalein : pink
methyl orange : yellow
bromophenol blue : blue

Question 31

What is a universal indicator?

Answer 31

it is a mixture of several indicators which changes colours at different pH values.

Question 32

What is the function of universal indicator?

Answer 32

• whether solution is acid or alkali

- how strong / weak