11 Air and Water Flashcards
what colour is Hydrated Copper(II) sulfate crystals
Blue
What colour is anhydrous copper (II) sulfate crystals
white
What colour is hydrated cobalt(II) chloride
pink
What colour is anhydrous cobalt(II) chloride
blue
What are the two tests for water
Hydrated Copper(II) sulfate ⇌ anhydrous copper(II) sulfate + water
Hydrated cobalt(II) chloride ⇌ Anhydrous cobalt(II) chloride + water
Why is water treated
To make it potable (safe to drink)
Explain the stages of water treatment (2)
Filtration - used to filter out large floating materials (microorganisms remain)
Chlorination - Chlorine gas bubbled through water to kill microorganisms. (May make water acidic but it is further treated with alkali to make it neutural)
Composition of air (3)
78% nitrogen
21% oxygen
1% noble gases, water vapour,
carbon dioxide
Common pollutants in the air (3)
Carbon monoxide
Nitrogen oxides
Sulfur dioxide
Sources of the common pollutants (3)
Carbon monoxide - produced during the incomplete combustion of fossil fuels or other carbon sources
Nitrogen oxide - Car engine
Sulfur dioxide - combustion of fossil fuels with sulfur compounds inside
Adverse effects of consuming common pollutants (3)
Carbon monoxide - poisonous gas that combines with hemoglobin preventing them from carrying oxygen
Nitrogen oxides - Combines with water in the air to form acid rain
Sulfur dioxide - causes acid rain, which can damage building and living organisms
How can sulfur pollutants be reduced? (2)
Using low sulfur fuels (which had a lot of sulfur removed at oil refineries)
Using flue gas desulfurisation
What are catalytic converters and what do they do (2)
fitted in cars to ensure toxic nitrogen and carbon monoxides are not emitted
Harmful gases passed over a hot catalyst converting them into less harmful gases
How do catalytic converters look
honeycomb shape
What reactions occur in catalytic converters (3)
2CO + O2 → 2CO2
2NO + 2CO → N2 + 2CO2
2NO → N2 + O2
Define corrosion
when a reaction between a metal and oxygen leads to a layer of metal oxide being formed on the surface of the metal
What happens when iron corrodes (2)
very brittle coating known as rust forms
eventually the iron will weaken and fall apart
What are the conditions required for iron to corrode (2)
water
oxygen
Equation for iron corrosion
iron + water + oxygen —> hydrated iron(III) oxide
2Fe + 2H2O + O2 —> Fe2O3.H2O2
How to prevent rusting
Using barrier that stops water and oxygen from coming into with the iron
What is galvanisation
coating iron in a layer of zinc
Role of zinc in galvanisation (2)
acts as a barrier against air and water
if zinc is damaged, it will offer SACRIFICIAL PROTECTION
How does sacrificial protection work? (2)
more reactive metals corrode in preference to less reactive metals (above reactivity series), metal can be protected from corroding.
The more reactive metals give away electron to less reactive metal, turning the less reactive metal into an ion
Natural sources of CO2 (3)
volcanic eruptions
respiration by living organisms
naturally occuring fires
Artificial sources of CO2 (3)
Burning fossil fuels
Deliberate forest fires
Production of cement
Main sources of methane (3)
paddy fields, where rice is grown
digestive processes in farm animals
anaerobic decomposition of waste in landfills
What are greenhouse gases
gases in the earth’s atmosphere that trap heat
does CO2 and methane contribute to greenhouse gases?
yeah
What are the essential elements needed for healthy plant growth (3)
nitrogen
phosphorus
potassium
Define fertilisers
compounds that can be added to a plant to help them grow
What are NPK fertilisers
fertilisers that contain nitrogen, phosphorus and potassium
What is the haber process used to create
Ammonia (NH3)
Eqt for haber process
N2 + 3H2 ⇌ 2NH3
How are the raw resources needed for the haber process collected? (2)
Nitrogen is extracted from the air through fractional distillation
Hydrogen is produced by reacting methane/natural gas with steam
What are the raw resources needed for haber process (2)
nitrogen
hydrogen
What catalyst does the haber process use?
Iron (III) oxide catalyst to lower temperature
What is the pressure used in the haber process
200 atm, to achieve a high yield of ammonia
Why is the temperature used in haber process 450 degrees?
To make process more economical
What is the displacement reaction that produces ammonia?
ammonium salt + strong base → ammonia + salt + water
