4 - Non Metals

Question 1

What is oxygen, nitrogen and carbon dioxide used for?

Answer 1

Oxygen used in hospitals
Nitrogen in packets (crisps, fruit) and making ammonia
-Carbon dioxide is used in fizzy drinks and fire extinguishers

Question 2

What are the uses of helium, neon and argon?

Answer 2

Helium- cools the cells in body scanners
Neon - glows red in low pressure tubes
Argon - lightbulbs stop hot metals reacting with oxygen in the air

Question 3

Describe the process of splitting water by electrolysis

Answer 3

• electrolysis can split water into elements, hydrogen and oxygen.
• Water is a covalent compound and so it’s a poor conductor of electricity
• however it contains a few free h+ and OH - ions. This conductivity of water can be improved by adding an acid which releases more ions so that more current flows during electrolysis which creates more hydrogen and oxygen

Question 4

Chemical equations for electrodes during the electrolysis of water? (Redox)

Answer 4

Negative:
2H+ + 2e = H2 (reduction)

Positive:
4OH- = 2H2O + O2 + 4e- (oxidation)

Question 5

What is the overall equation for the electrolysis of water?

Answer 5

2H2O = 2H2 + O2

Question 6

Why does twice as much hydrogen form as oxygen?

Answer 6

Because there are two hydrogen atoms and only one oxygen atom for each water molecule

Question 7

How do hydrogen fuel cells work?

Answer 7

There are electrochemical energy conversion devices that work by combining hydrogen with oxygen from the air to form water, producing electrical energy in the process.
-hydrogen can replenished

Question 8

3 advantages of hydrogen fuel cells

Answer 8

• no pollution produced
• renewable source of energy
• produces lots of energy

Question 9

3 disadvantages of hydrogen fuel cells

Answer 9

• availability of hydrogen is limited
• difficult to store the hydrogen
• card are expensive

Question 10

3 advantages of fluoride

Answer 10

• reduces tooth decay
• no evidence of any health risks to human health
• very safe

Question 11

2 disadvantages of fluoride

Answer 11

• causes problems if too much is consumed (discoloured teeth)
• too much fluoride could be a risk factor for types of bone cancer

Question 12

Fluorine appearance, properties, uses..

Answer 12

Pale yellow- brown gas
Very reactive: toxic
Reduces tooth decay

Question 13

Chlorine appearance, properties, uses..

Answer 13

Pale yellow-green gas
Poisonous/toxic
Kills bacteria

Question 14

Bromine appearance, properties, uses

Answer 14

• red brown gas/liquid
• poisonous/toxic
• kills bacteria

Question 15

Iodine appearance, properties, uses

Answer 15

Metallic grey solid/ purple gas
Poisonous/toxic
Kills bacteria

Question 16

Where are chlorine and iodine found?

Answer 16

In seawater

Question 17

How is chlorine produced?

Answer 17

By the electrolysis of BRINE. An electric current is passed through the brine. Chlorine gas is produced at the anode and hydrogen gas at the cathode

Question 18

How do we test for chlorine?

Answer 18

Damp blue litmus paper is bleached

Question 19

What is iodine solution used for?

Answer 19

An antiseptic to clean wounds

Question 20

Why are some people opposed to fluoridation of drinking water but noone opposes chlorination?

Answer 20

• excess fluoride discolours teeth and causes fluorosis
• may cause brittle bones, IBS, and maybe even bone cancer
• chlorination makes water safe to drink

Question 21

What is the test for hydrogen?

Answer 21

A lighted splint makes a popping sound in a test tube of hydrogen

Question 22

What is the test for oxygen?

Answer 22

A glowing splint relights in a test tube of oxygen

Question 23

What is the test for carbon dioxide?

Answer 23

Bubbling carbon dioxide in limewater turns the limewater cloudy white

Question 24

What is the test for ammonia?

Answer 24

-damp red litmus paper turns blue

Question 25

What is the test for chlorine?

Answer 25

-turns damp blue litmus paper red, and then bleaches it red

Question 26

What gases are in the air?

Answer 26

• oxygen
• nitrogen
• carbon dioxide
• (water)
• argon
• neon
• krypton
• xenon