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Heat

Heat. Combustion. of. Some Questions!. In chemical terms what are we talking about when we mean the heat of something?. What are we talking about when we mean the heat of combustion?. What is required for combustion to occur?. Heat of Combustion definition.

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Heat

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  1. Heat Combustion of

  2. Some Questions! In chemical terms what are we talking about when we mean the heat of something? What are we talking about when we mean the heat of combustion? What is required for combustion to occur?

  3. Heat of Combustion definition The heat of combustion of a substance is the heat change in kilojoules, when one mole of the substance is completely burned in excess oxygen.

  4. Turning up the Heat What does this tell us about petrol? Why are we trying to cut down the emissions from petrol?

  5. Gas Guzzlers When we burn octane (petrol) the equation is… C8H18 + 12½O2 → 8CO2 + 9H20 CO2 is harmful for environment and increases GHGs When we burn hydrogen the equation is… H2 + ½O2 → H20 Water is the main by-product which is harmless So why can’t we just use hydrogen powered cars?

  6. Gas Guzzlers contd…

  7. Measuring up…. Can we measure the heat of combustion the same way we measure the heat of reaction? Answer: Our polystyrene cup isn’t sufficient to measure HoC. How do we measure it then? Answer: A bomb calorimeter How does it work?

  8. Measuring up…(contd)

  9. Measuring up contd…

  10. Kilogram Calorific Values Recap: Specific Heat Capacity measures the energy required to change 1kg of substance by 1 degree KCVs measure the heat energy produced by 1kg of fuel! Is there any other substance that has a calorific value?

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