[Year 2] CI

• Raw materials: cheaper, but must be widely available to ensure good sustainable supply. • Energy: required in manufacturing and transport, high TP increases costs. Purification of products also needs to be considered. • Waste: from by-products, due to gov regulations costs. Co-products can be sold off (although at a lower price). • High atom economic and percentage yields.

Pressure: • Pros: beneficial to gas reactions, as high pressure speeds up the rate of reaction. • Cons: pumps, thicker pipes and vessels, and additional safety equipment are needed (which are expensive to run). Catalysts: • Pros: allows reactions to run quickly at lower temps, saving money. Can be reused. • Cons: expensive, homogeneous catalyst must be separated after the reaction (additional step increases costs). Temperature: • Pros: Higher temps = faster rate of reaction, more product per unit time. • Cons: More fuel needed, therefore more expensive.

• Dynamic equlimbrium is met. • This is where the rate (Con/Time) of forward reaction = rate of backwards. • At this point the concentrations remain constant. • ONLY occurs in a closed system.

• Only valid for one temperature. • Changing the temperature will change the equilibrium concentrations, and hence Kc will change too. • If temp change causes equilibrium to shift right, Kc INCREASES. • If temp change causes equilibrium to shift left, Kc DECREASES. • This can be explained using the Kc expression of a reaction.

No effect

No effect. • catalyst speed upi the rate of forward AND reverse reaction. • so speed up the rate at which equilibrium is established.

Temp: 400ᵒC ∵ although it shifted the equilibrium to the left (as the forward reaction is exo), this is so the rate of reaction isn’t so small that it takes too long. 200atm ∵ although a high pressure would favour the forward reaction (due to moles), high pressures are expensive and can be dangerous. For these reasons both of these are compromised.

Adv: • Parmaceutcals help prevent and cure disease. • Fertilisers ensure food is produced in the most efficient way possible • Plastics are widely used today. • Dyes and cleaning procus have helped improve living environment and lifestyle. Dis: - Some chemicals can be harmful to the environment. (gases = air pollution) (liquid/solid = land pollution). - Some chemicals are flamalble and explosive (must be stored and handled correctly. - Some chemicals can be harmful to our health (via inhalation or contact).

Kc = [C]²[D] / [A]²[B]

Colourimetry: • Coloured solutions absorbs particular wavelengths of light. • This can be used to determine the absorption of the wavelength of light of the reaction at equilibrium. • A calibration curve of known concentrations can be plotted. • Our test sample is compared to these. pH: • Useful if reactant and products have different pH values. • pH can be measured at equilibrium. • pH equation can then be used to calculate the concentration.

Initial moles Change in moles Equilibrium moles Equilibrium moles/vol = Equilibrium concentration Kc = [products] / [reactants]

1s¹ 2s² 2p³

Nitrogen is diatomic with triple covalent bonds which is required a lot of energy to break.

The Haber Process: - the reaction between N₂ and H₂. N₂ + 3H₂ ⇌ 2NH₃

• It shares 3 of its valence electrons with hydrogen and a lone pair of electron remains. • As a result it can form H-bonds with water, and so is very soluble. • It can also form dative covalent bonds using its lone pair of electrons (although these are not as strong as standard covalent bonds). • As a result of its lone pair, is also acts as a base to form ammonium ions (this N-H bonds is dative).

• N₂O (Nitrogen(I) oxide/ Dinitrogen oxide): colourless gas with sweet smell. • NO (Nitrogen(II) oxide/ Nitrogen monoxide): colourless gas. • NO₂ (Nitrogen(IV) oxide/B Nitrogen dioxide): Brown gas with sharp, pungent smell.

Litmus paper. • Add sodium hyrodxide • Heat, if ammonium is present amonia gas will be produced. • Use damp red litmus, this will turn blue as ammonia dissolves in the water.

Using sodium hydroxide and aluminium/ dervarda’s alloy. • add sodium hydroxide and aliminium foil/Devarda’s alloy to the solution you want to test. • Heat. • If nitrate(V) ions are present they are reduced by aluminium to ammonia gas. • Use damp red litmus, this will turn blue as ammonia dissolves in the water.

N₂ + 3H₂ → 2NH₃

NH₃ + H⁺ → NH₄⁺

NH₄⁺ + O₂ → NO₂⁻ + 4H⁺ + 2e⁻

NO₂⁻ + H₂O → NO₃⁻ + 2H⁺ + 2e⁻

2NO₃⁻ + 12H⁺ + 10e⁻ → N₂ + 6H₂O

N₂ + O₂ → 2NO N₂ + 2O₂ → 2NO₂ 2N₂ + O₂ → 2N₂O