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ACID SYNTHESIS

01/18/2015

[
Topic
Acidic,
basic
and
amph
oteric
oxides

Syllabus Dot points
Identify oxides of non- metals which
act as acids and describe the
conditions under which they act as
acids

Summary
Acidic oxides are non metallic oxides
- React with water to form an acid
- React with bases to form salt
- E
...
co2, no2 , diphosphrous pentaoxide
Basic oxides are metallic oxides (ionic bonding)
- React with water to form alkali
- React with acids to form salts
- E
...
g
...


Acidic Oxide:
An acidic oxide is generally oxides of non-metals
...
Elements that have acidic oxides occur
towards the right and top of the periodic table
...
Most non-metals (other than the noble gases) form
acidic oxides
...


Basic oxides:
Basic oxides are oxides of metal
...

Elements on the left hand side of the periodic table tend to
form basic oxides, they tend to have low electronegativity
...
The
basicity of these oxides increases down each group
...

Amphoteric oxides:

ACID SYNTHESIS

01/18/2015

Some oxides like ………………………………………………… react with
acids to form salts but also react with alkalis
...

Amphoteric oxides does not lie in left or right of the periodic
table but lie somewhere in the transitional element section
...


Natural SO2 sources:
- Geothermal hot springs and volcanoes
- Natural decay of vegation on land, in wetlands and
oceans
Industrial SO2 Sources
- Burning of fossil fuels contained S such as coal and
oil
Eqn:
-

Extraction of metal from sulfide ore

Eqn:

-

Natural No2 sources
Lightning

Eqn

-

Action of microorganisms (bacteria) on nitrogenous
material in soil

Industrial sources of No2
Combustion in stationary sources (power stations)
and moving ones (car and trucks) The exhaust from
power stations and vehicles contain No and No2
...


S + O2  SO2 (burning of fuels)
2ZnS +O2 ZnO +So2 (extraction of metal from ore)
No2 equations:
O2+ N2  2NO (lightning)

Analyse information from secondary
sources to summarise the industrial
origins of sulphur dioxide and oxides
of nitrogen and evaluate reasons for
concern about their release into the
environment
...
At high
concentrations it causes extensive tissue damage
...
The increased
concentrations of sulphur and nitrogen oxides increases

ACID SYNTHESIS

Eviden Assess the evidence which indicates
ce for increase in atmospheric concentration
increa of oxides of sulphur and nitrogen
...


01/18/2015

formation of acid rain and photochemical smog – the latter a
form of air pollution
...
In some
cases, acid rain can cause leaching of aluminium from soils
into river and cause death of aquatic life and health
problems for people in affected areas
...

The release of oxides of nitrogen also lead to formation of
photochemical smog
...

Hence the increase in acid rain implies in an increase in
levels of these oxides in the atmosphere
...

2) Whereas atmospheric CO2 concentrations are about 360
ppm, the levels for SO2 and NOx are only about 0
...
Thus it is much more
difficult to detect
...

3) Technology to directly measure concentration of No2 and
So2 has only been available since mid-1970s hence
evidence before 1970s may be unreliable
...
This results in any atmospheric
measurements of their presence inaccurate and their
validity questionable
...


ACID SYNTHESIS

01/18/2015

Effects:
- Increasing lake acidity (chronic acidity, acid dissolve
aluminium affect availabily of nutrients in soil) so
lower ph levels and higher concentrations of
aluminium toxic to fish  leaching of toxic metals;
lower ph levels affects reproduction of aquatic
animals, kill eggs and fishes)
- Damage to vegetation and forests
(leaches essential metal nutrients , dying from
nutrient deficiency) (soil erosion)
- Erosion of status and buildings that contain calcium
carbonate ( react readily with sulphuric acid to cause
physical weathering of structures)
Calcul
ating
gas
volum
es

Calculate volume of gases given
masses of some substances in
reactions, and calculate masses of
substances given gaseous volumes, in
reactions involving gases at 0 degree
Celsius and 100 kPa or 25 degree
Celsius and 100 kPa
...
71
Room temperature -25 degree Celsius
N= V/24

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