Topic 3 - Acids

Question 0

What do indigestion remedies do?

Answer 0

They contain substances that neutralise excess stomach acid.

Question 1

Why does the stomach produce Hydrochloric acid?

Answer 1

• help digestion. Enzymes break down food work better

- kill bacteria. Food poisoning less likely.

Question 2

What are hazard symbols used on containers for?

Answer 2

They indicate the dangers associated with the contents and are used to inform people about safe working procedures with these substances in the laboratory.

Question 3

Give 3 ways acids are neutralised

Answer 3

Metal oxides
Metal hydroxides
Metal carbonates to give a salt

Question 4

What are bases usually?

Answer 4

Metal oxides or hydroxides

Question 5

Hydrochloric acid + sodium hydroxide —- ?

Answer 5

Sodium chloride + water

Question 6

What is the general equation for BASHO

Answer 6

Base + acid —- salt+water

Question 7

What is the general equation for CASHOCO

Answer 7

Carbonate + acid —- salt, water, carbon dioxide

Question 8

What is Hydrochloric acid +sodium carbonate

Answer 8

Sodium chloride + water + carbon dioxide

Question 9

What is electrolysis? Which current does it use?

Answer 9

The decomposition of a compound using electrical energy. The electricity used comes from a d.c. E.g. Battery

Question 10

What is an electrolyte? Electrode? What does the electrode contain?

Answer 10

Electrolyte - the liquid used to conduct the electricity
Electrode - what the electricity is applied to the electrolyte by
The electrolyte contains the compound which is broken down into its component parts.

Question 11

Describe the electrolysis of Hydrochloric acid

Answer 11

The electrolyte is a dilute solution of Hydrochloric acid.
Applying a d.c. Current causes the Hydrochloric acid to decompose into its two component parts : hydrogen gas and chlorine gas
The gases bubble through the solution and can be collected at the electrodes.

Question 12

What is the chemical test for chlorine?

Answer 12

Dip some damp litmus paper into the potential chlorine and although it may turn red at first since chlorine solution is acidic, if chlorine is present, it will bleach the litmus paper white.

Question 13

What is the chemical test for hydrogen?

Answer 13

Put a lighted splint into the potential hydrogen. If there is a squeaky pop, hydrogen is present.

Question 14

What is the chemical test for oxygen?

Answer 14

Light a splint then blow it out so it is glowing. Put it into the potential oxygen and if the splint relights, oxygen is present.

Question 15

U can chlorine be obtained from sea water?

Answer 15

Electrolysis

Question 16

Why is the manufacture of chlorine gas difficult?

Answer 16

Chlorine is toxic and this can lead to problems associated with its large scale manufacture.

Question 17

What are three uses of chlorine?

Answer 17

It is used to treat water supplies as it kills bacteria etc. so water is safe to clean.
Used to make bleach
Used to make the polymer poly(chloroethene) which is aka PVC

Question 18

What two products can water be decomposed by electrolysis to produce?

Answer 18

Hydrogen
Oxygen
(G)