Chapter 16 - Gas chemistry

Question 1

What is the composition of gases in the atmosphere ?

Answer 1

nitrogen - 78%
oxygen - 21%
0.03-0.04% - carbon dioxide
1% - argon
small amount of noble gases 
small amount of water vapour

Question 2

What are the physical properties of nitrogen ?

Answer 2

• colourless odourless gas
• neutral
• insoluble in water

Question 3

Why does nitrogen have a lack of reactivity ?

Answer 3

due to its strong triple covalent bond

Question 4

what are two uses of nitrogen ?

Answer 4

• used in food packaging to create an inert atmosphere to keep the food fresh
• liquid nitrogen is used to freeze foods to keep them fresh

Question 5

What is the test for ammonia ?

Answer 5

• hold a glass rod covered in HCL near the gas

- if ammonia present a white smoke is formed

Question 6

What is the use for ammonia in industry ?

Answer 6

its reacted with acids to make ammonium salts which are used as fertilisers

Question 7

What is the lab preparation and collection for hydrogen ?

Answer 7

React a metal and dilute HCL to produce hydrogen.

hydrogen can be collected over water as its insoluble
use a delivery tube and a beehive shelf

Question 8

What are the physical properties of hydrogen ?

Answer 8

• colourless odourless gas
• insoluble in water
• less dense than air
• neutral

Question 9

What are some uses for hydrogen ?

Answer 9

• used in weather balloons
• used in hardening oils
• potential clean fuel

Question 10

What is the lab preparation and collection for oxygen ?

Answer 10

hydrogen peroxide slowly decomposes to produce water and oxygen. Speed this process up by using manganese dioxide.

collect above water through a delivery tube into a beehive shelf

Question 11

what are the physical properties of oxygen ?

Answer 11

• neutral
• colourless, odourless
• slightly soluble in water

Question 12

What are some uses for oxygen ?

Answer 12

• used for patients with breathing difficulties

- welding

Question 13

What are the observations before and after magnesium reacts with oxygen ? And are the products acidic or basic ?

Answer 13

grey solid - white light - white solid

basic oxide

Question 14

What are the observations before and after copper reacts with oxygen ? And are the products acidic or basic ?

Answer 14

red-brown solid - blue-green flame - black layer on copper

basic oxide

Question 15

What are the observations before and after iron reacts with oxygen ? And are the products acidic or basic ?

Answer 15

grey solid - orange sparks - black solid

basic oxide

Question 16

What are the observations before and after sulfur reacts with oxygen ? And are the products acidic or basic ?

Answer 16

yellow solid - blue flame - colourless gas

acidic oxide

Question 17

What are the observations before and after carbonreacts with oxygen ? And are the products acidic or basic ?

Answer 17

black solid - orange sparks - colourless gas

acidic oxide

Question 18

What are the uses of carbon dioxide ?

Answer 18

• make fizzy drinks

- used in fire extinguishers

Question 19

What is the lab preparation and collection for carbon dioxide ?

Answer 19

react calcium carbonate and HCL produces CO2

Collect over water using a delivery tube and a beehive shelf, over water.

Question 20

What is produced when you react carbon dioxide and water ?

Answer 20

carbonic acid is formed

Question 21

What are the properties of CO2 ?

Answer 21

• colourless, odourless
• slightly soluble in water
• acidic
• denser than air