Transcript
Collision Theory
Particles must collide with each other with enough energy to react Temperature, surface area, catalysts, concentrations of substances •
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How fast?
Rate = amount of reactant used (or products formed) / time Measure the amount of gas given off a reaction every 10 seconds, or weigh the reaction every 10 seconds •
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The Effect of a catalyst
It lessens the amount of energy needed, therefore making the reaction cheaper Catalysts are often efficient for only one reaction •
Chemistry Rates of Reaction Answers
The effect of concentration
The particles are closer together and therefore collide more often
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The effect of Temperature
The particles have more energy, therefore move faster, colliding more frequently and with more energy 10oc 10oc •
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Reversible Reactions
Making Ammonia – Haber process
When the reactants react to make products, which then react again to make reactants It reaches equilibrium By altering concentration on conditions
Nitrogen and Hydrogen Iron, 450oc, 200 atmospheres They are recycled and put through the process again 20% BUT It is quick and there are no waste products
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Chemistry A metal that is found pure, not in an ore, e.g. gold. Zinc, iron, copper, lead, tin Aluminium, magnesium, potassium Reduction is the removal of oxygen in a compound Iron (III) oxide, coke, 4% impurities (makes it hard and brittle, only used for cast iron but roduces steels •
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Chemistry
Chemistry
Saturated Hydrocarbons are hydrogen and carbon only and they contain as much hydrogen as possible on each molecule. Alkanes are saturated, Alkenes are unsaturated (they contain one or more double bond).(
Because the substances in it burn in different conditions. Fractional distillation Compounds containing only carbon and hydrogen. Molecular formula and structural formula
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CnH2n+n
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Chemistry They stop the suns heat escaping the earth atmosphere causing global warming. Global dimming is particulates of carbon and hydrocarbons reflecting the suns rays. We can reduce the amount of sulphur in the fuels or in the exhaust gasses after they are burnt. •
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Chemistry The oil is vaporised, and sent into a fractional distillation column. Here they’re they’re separated by gasses with different boiling points condensing at different levels, lowest boiling points (small (small carbon chains) at the top (gas) and highest at the bottom (for making roads – long carbon c hains). These are more difficult to burn. •
Chemistry Incomplete combustion takes place in places with little air supply (like engines). It can produce carbon particles and carbon monoxide. Also fuels that that contain sulphur can produce sulphur dioxide. Sulphur dioxide causes acid rain, Carbon particles cause global dimming and carbon dioxide causes global warming. •
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