General Knowledge Flashcards

Question

What are limitations of the LCA?

Answer 1

Limitations of LCA, involves more steps then just those 4. difficult to assess harm So complex, so easily manipulated to deliberately support a compnay

Answer 2

Low levels of dissolves substances PH of between 6.5-8.5 No microorganisms swimming within

Answer 3

1) Pass fresh water through a wire mesh to filter out any big things like sticks or rocks 2) Pass fresh water through a bed of sand and gravel to filter out smaller bits 3) Sterilise it to kill any microbes, which is done by bubbling chlorine gas, ozone, or UV light

Answer 4

Distillation and Reverse Osmosis are very expensive , produces brine - Simple Distillation, larger quantity with a different apparatus and collect pure distilled water - Reverse Osmosis, salty water passed through a membrane, which traps all ions and larger molecules, only allowing water molecules through, ending up with pure distilled water

Answer 5

Domestic – Household Waste, Shower, Sink's, Toilets to sewers Agricultural – Nutrient runoff and animal waste Industrial – Factories that make and use chemicals

Answer 6

1) Screening Sewage is passed through a mesh or screen to remove large objects like sticks, plastic, or bottles. 2) Sedimentation The sewage sits in a settlement tank where: Heavier solids sink to form sludge Lighter liquid (effluent) remains on top 3) Separation Sludge and effluent are pumped into separate tanks 4) Biological Treatment Effluent is treated under aerobic conditions (air pumped in) → aerobic bacteria break down organic matter Sludge is treated under anaerobic conditions (sealed tank) → anaerobic bacteria break it down 5) End Products Treated effluent is safe to release into rivers or lakes Sludge produces: Methane gas → used for energy Remaining solids → used as fertiliser

Answer 7

1) Reactant Input Hydrogen and nitrogen gases are fed into the reaction vessel (nitrogen from air, hydrogen from natural gas). 2) Reaction Conditions Inside the vessel: Temperature: ~450 °C Pressure: ~200 atm Catalyst: Iron These conditions favour a reasonable yield and rate. Reversible reaction: So the mixture contains both ammonia and unreacted hydrogen/nitrogen. 3) Condensation of Ammonia The gas mixture is passed through a condenser. Ammonia, with a low boiling point, liquefies on cooling. 4) Recycling Unreacted Gases Unreacted nitrogen and hydrogen remain gaseous due to a lower BP and are recycled back into the reaction vessel to improve efficiency.

Answer 8

We use 450 degrees as the reaction is exothermic, so we need a low temperature to favour the forward reaction, to achieve a higher % yield, however to achieve a high rate of reaction, we need a high temperature for particles to gain plenty of kinetic energy in order to react 450 degrees is chosen as a compromise, for a lower yield yet a higher rate of reaction Generating heat is also very expensive

Answer 9

We use 200 atm, as to achieve a high yield, there are fewer molecules of products then reactants, so a high pressure shifts equilibrium to the right We also want a high pressure to achieve a high rate of reaction, as a high rate of reaction means particles collide more frequently Practical limitations of cost and safety is what limits us to 200 atm

Answer 10

Nitrogen is important to make amino acids, proteins, which are essential for growth Main source of nitrogen in fertilisers is ammonia, gathered from the Haber Process Ammonia + Oxygen and Water = Nitric Acid Ammonia + Acids = Ammonium Salts

Answer 11

Phosphate can be mined from the ground as phosphate rock However, because phosphate salts in the rock are insoluble, plant's cannot use them as nutrients Instead, we have to react the phosphate rocks with acids to make soluble salts Phosphate Rock + Nitric Acid = Phosphoric Acid + Calcium Nitrate Phosphate Rock + Sulfuric Acid = Calcium Sulphate + Calcium Phosphate = Single Superphosphate Phosphate Rock + Phosphoric Acid = Calcium Phosphate = Triple Superphosphate

Answer 12

Potassium chloride and potassium sulphate can both be mined from the ground and used directly in fertilisers

Answer 13

- Grow plants in copper rich soil and waste - Extract plants, burnt them and extract copper from the ash as the plant absorbs copper into their roots to form copper compounds - Extract copper with either electrolysis or a displacement reaction - Great for extracting low grade ores - Much longer and slower - Requires lot's of lands

Answer 14

- Take bacteria and grow it on the metal ore - They produce a leachate solution that contains loads of metal ions - Separate using electrolysis or displacement reaction - Great for extracting low grade ores - Much less environmental damage - Require much less energy and cost - Much longer and slower - Produces some toxic pollutants

General Knowledge Flashcards

(38 cards)