Adds nutrients for plant growth (such as NO3 -, PO4 3-, K +)
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What does manure do to plants?
Adds organic matter for plant growth and soil improvement
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What does lime or chalk to do plants?
Alters the pH of the soil
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What do pesticides do and what important feature do they need to have?
Can increase crop yeilds. Need to be biodegradable so they don't accumulate in food chains
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What do you need to consider when looking into risks and benefits for a given chemical process?
Hazards associated with raw materials, reactants, products and by-products, explosions, acidic gases, flammable gases and toxic emissions
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What are the principles of green chemistry?
Minimum waste; reduce feedstock consumption; reduce energy consumption
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Describe a giant ionic lattice
Compounds of metal and non-metal ions with strong ionic bonds. High melting point, hard, brittle, conduct when molten/dissolved, often soluble in water, generally insoluble in non-polar solvents
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Describe a giant covalent network lattice
Elements and compounds of group 4 with strong covalent bonds. Very high melting point, very hard (if 3D), don't normally conduct (except graphite), insoluble
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Describe a giant metallic lattice
Positive metal ions surrounded by delocalised electrons. Strong metallic bonds. Generally high melting point, Hard but malleable, conduct when solid or liquid, insoluble but some react with water
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Describe a simple covalent molecule
Some non-metal elements and compounds with week intermolecular bonds and strong covalent intramolecular bonds to form small molecules. Low melting point, soft, don't conduct, usually insoluble in water, usually soluble in non-polar solvents
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Describe a covalent macromolecule
Polymers with weak intermolecular bonds and strong covalent intramolecular bonds. Moderate melting point (often decompose on heating). Many are soft but often flexible, don't normally conduct, usually insoluble in water, sometimes soluble in solvents
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What's the equilibrium law?
Kc = Concentrations of products / Concentrations of reactants
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What is the equilibrium constant?
K. When written in terms of concentrations, it's Kc.
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What affects the value of Kc?
Temperature only.
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What are the raw materials for the manufacture of ammonia (the Haber process)?
Air and natural gas. From which a feedstock of nitrogen and hydrogen (ration 1:3) is made
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What are the usual conditions for the Haber process?
iron catalyst, 450 degrees C. 200 atm. These are compromise values to produce reasonable yield at acceptable rate
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What's the equation and enthalpy change for the haber process?
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