C11 Ammonia

Question 1

Ammonia

Answer 1

Alkaline gas made in the Haber process from nitrogen and hydrogen. NH3

Question 2

Ammonium Salts

Answer 2

Ammonium nitrate, sulfate or chloride. Made by neutralizing ammonia with a particular acid. Very soluble and useful as a chemical fertilizer

Question 3

Fertilizer

Answer 3

Compounds that contain vital elements required for healthy growth of plants. These mainly include the elements NPK (nitrogen, phosphorous, potassium)

Question 4

Litmus paper

Answer 4

Used as a test for the alkaline nature of ammonia gas. Damp red litmus paper turns blue

Question 5

Leaching

Answer 5

High solubility of chemical fertilizers in water means that they may be washed from the land into local streams and rivers, causing eutrophication.

Question 6

How to reduce leaching

Answer 6

using less fertilizer and by not using before heavy rain

Question 7

Eutrophication

Answer 7

Large amounts of fertilizer in streams and rivers causes excess growth of plants. When this dies and decays, the bacteria responsible for this uses up oxygen in the water and results in decreased dissolved oxygen content. Means marine life that requires high oxygen content cannot survive

Question 8

Nitrogen fixation

Answer 8

The process by which nitrogen from the air can get into a soluble form that plants can take up in their roots. Due to the unreactive nature of nitrogen this can be achieved by nitrogen fixing bacteria and in the high temperatures created by storms. Nitrogen fixation can also be achieved in the Haber process.

Question 9

Catalysts

Answer 9

Speed up rate of chemical reaction but are not used up in the process. Many transition metals make effective catalysts

Question 10

Reversible reactions

Answer 10

reaction where the starting materials react to become products, but at the same time the products may decompose to become the starting materials. The rate of the forward and reverse reactions are equal and opposite. Often means that yield of product is low. Conditions such as temperature and pressure can be altered to give higher yields

Question 11

Haber process definition

Answer 11

A reversible reaction where nitrogen and hydrogen react to give ammonia. Process is favored by high pressures and low temperatures with an iron catalyst

Question 12

Uses of ammonia

Answer 12

production of nitric acid, fertilizer, pharmaceuticals, cleaning products and explosives

Question 13

The Haber process

Answer 13

1) 3H2 + N2 (reversible) 2NH3
Hydrogen + nitrogen ammonia
2) gases compressed and delivered to reactor (iron catalyst used). cooled down, ammonia liquefied.

Question 14

Where is the hydrogen needed in the haber process obtained

Answer 14

from the reaction of methane and steam- produces CO and H2

Question 15

Where is the nitrogen needed in the haber process obtained

Answer 15

Hydrogen produced from methane and gas reacts with oxygen in the air, producing water, and leaving nitrogen behind (air is 78% nitrogen)

Question 16

Conditions for haber process

Answer 16

1) High pressure- 200 atm
2) low temp- favors the forward exothermic reaction, but not that low; would take long to reach equilibrium
3) Iron catalyst- increases rate of equilibrium reached

Question 17

Le Chatelier’s principle

Answer 17

a reaction in high pressure favors the side with less moles (in the case of the haber process, the forward reaction- producing ammonia)

Question 18

Why can’t plants obtain nitrogen from the air

Answer 18

Nitrogen triple bond very strong, so it has to be fixed into soils and dissolved in water and absorbed by roots

Question 19

The production of nitric acid from ammonia

Answer 19

1) 4NH3 + 5O2 -> 4NO+6H2O (with a platinum catalyst)
ammonia+ oxygen-> nitrogen monoxide +water
2) 2NO + O2 -> 2NO2
Nitrogen monoxide+ oxygen -> nitrogen dioxide
3) nitrogen dioxide and oxygen dissolve in water to form nitric acid

Question 20

Composition of air

Answer 20

78% nitrogen
21% oxygen
1% other

Question 21

Are ammonium salts soluble or insoluble in water?

Answer 21

It depends if there are mobile ions, such as K+, Na+,NH4+

Question 22

Smell of ammonia gas

Answer 22

Pungent/ bad smell

Question 23

Nitrogen fixing bacteria

Answer 23

they take nitrogen out of the air, and when they decompose/ decay, the nitrogen can be absorbed by plants