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Help me understand

  1. Jul 27, 2005 #1
    Help me understand plz

    0.6 mole of O2, 0.8 mole of CO and 0.5 mole of CO2 are added to a 2-L container. The system is heated and 0.15 mole of CO2 is formed.

    Does that mean that on top of the initial 0.5 mole of CO2 an additional 0.15 mole of CO2 is formed or does that mean that in total (at equilibrium) 0.15 mole of CO2 has been formed?

    Anyone? thx :yuck:
  2. jcsd
  3. Jul 27, 2005 #2


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    I would imagine that it means that an additional .15 mol of [itex]CO_2[/tex] is formed because the equillibrium of that reaction favors formation of [itex]CO_2[/tex] heavily.
  4. Jul 27, 2005 #3
    This is the reaction O2 + 2CO --> CO2

    When you heat the container, the reaction shifts to the product side.
    You can think of heat energy as something that can be written as a reactant or product. So if the equation shifts to the rights when heat is added, the heat must be on the left. Le Chatlier's Principle says that when a stress is placed on a system the system will shift to relieve that stress. So by shifting to the right, it is relieving the stress whcih is on the left.

    So we have: HEAT + O2 + 2CO --> CO2

    We can learn from this that the reaction is probably endothermic (heat added), but we cannot be sure because by heating the container we introduce another stress, increased pressure.

    When Pressure is increased in a closed container at equilibrium the reaction will shift in whichever direction will relieve that pressure. Since fewer particles will result in less pressure, the reaction will shift toward the side which has the fewest moles of gas (in this case the products have 1 mole while the reactants have 3 moles).

    There are always multiple ways to approach problems in the sciences and math and these are two common ways one might approach this one. Hope this helps.
  5. Jul 27, 2005 #4


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    It means an additional 0.15 moles of CO2 were formed. Practically an english question. "is formed" should give it away i suppose.
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