Rates of change (AS)

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In an AS course you only have to have a qualitative understanding of the factors which affect the rates of reaction. The main factors to consider are temperature, concentration (or pressure for gases) and the presence of catalysts.
 
When answering the question 'How fast?' chemists find it helpful to think in terms of the activation energy for reactions.

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Webguides

• Understanding activation energies

Recently Asked Questions

• What is the method for using an inverted burette or a gas syringe to measure gas produced in a thermal decomposition reaction? I have searched everywhere on the internet and in books but I can't find any detailed explanations. I am looking specifically at the thermal decomposition of hydrogen peroxide of different concentrations at room temperature using catalase.
• In the reaction between sodium thiosulphate and sulphuric acid according to the written equation, solid sulphur happens to be a product of the reaction. I have also noticed that at the end of the reaction there is a very pungent odour which I deduced to be sulphur. I also thought that sulphur was a yellow pigment but at the end of the reaction the solution is transluscent or somewhat opaque, but not yellow - it seemed to be more cloudy than yellow. What explanation is there to this?
• How does pressure affect the rate of reaction?

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updated: 21 August 2003