8.5 Acid Deposition Flashcards Preview

Chemistry Chapter 8 - Acids and Bases > 8.5 Acid Deposition > Flashcards

Flashcards in 8.5 Acid Deposition Deck (12):
1

What is acid deposition?

Any process in which acidic substances leave the atmosphere to be deposited not he surface of the Earth.

2

Why is rain naturally acidic?

Due to dissolved carbon dioxide and has a pH of about 5.6

3

What is the process of carbon dioxide dissolving in water?

H2O (l) + CO2 (g) H2CO3 (aq) it dissolves to form carbon acid which then dissociates
H2CO3 (aq) H+ (aq) + HCO3- (aq)
Which then dissociates again
HCO3- (aq) H+ (aq) + CO3 2- (aq)

4

What is acid rain?

Rain with a pH lower than 5.6

5

What is acid deposition caused by?

When nitrogen oxides or suffer oxides dissolve in water to form nitric acid and sulphuric acids.

6

How is sulfur dioxide produced and what is the equation for the formation of sulphuric (III) acid?

By burning coal and other sulfur containing fuels, smelting of metal ores or volcanic activity.
S (s) + O2 (g) -----> SO2 (g)
The equation for the formation of acid:
SO2 (g) + H2O (l) ----> H2SO3 (aq)

7

How is sulfur trioxide produced and what is the equation for the formation of sulphuric (VI) acid?

Formed from S02 in the atmosphere.
2S02 (g) + O2 (g) 2SO3 (g)
The equation for the formation of the acid:
SO3 (g) + H20 (l) -----> H2SO4 (aq)

8

How is nitrogen oxide produced?

By internal combustion engines, coal, oil and gas fuelled power stations.
N2 (g) + O2 (g) -----> 2NO (g)
It can be converted to nitrogen dioxide.

9

How is nitrogen dioxide produced and what is the equation for the formation of nitric acid?

By oxidation of NO in the atmosphere.
2NO (g) + O2 (g) -----> 2NO2 (g)
The equation for the formation of nitric acid:
2NO2 (g) + H2O (l) -----> HNO2 (aq) + HNO3 (aq)

10

What are some effects of acid deposition?

Damages and kills trees and plants
Kills fish in lakes
Damages limestone buildings

11

How can sulfur be removed pre combustion?

The sulfur is removed from the fuel before it is burnt - used for producing petrol/diesel for vehicles this can be done by heating the duller containing fuel with hydrogen in the presence of a catalyst inverting sulfur to H2S.

12

How can sulfur be removed post combustion?

In a power station the sulfur oxides are removed after the fuel has been burnt. This can be done by the exhaust gases being passed through a base such as calcium oxide or calcium carbonated eg
CaCO3 (s) SO2 (g) ------> CaSO3 (s) + CO2 (g)