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Factors affecting reaction rates

Submitted by manijhis88 on Sat, 02/16/2008 - 17:06

Sparklers contain powdered iron. Why do sparklers burn more rapidly that a piece of iron wire? (Select all that apply.)
    The larger surface area of the iron powder increases the rate of reaction.
    Larger particles react more rapidly than small particles.
    Converting the iron to a powder makes it an ionic compound which reacts more rapidly.
    Smaller particles have a lower energy of activation than larger particles.
    Converting the iron to a powder makes it a catalyst.


    The larger surface area of the iron powder increases the rate of reaction.  -  True - increasing surface area speeds up the rate of a reaction by increasing the likelihood of effective collisions between the reactant molecules.
    Larger particles react more rapidly than small particles.  - False - this would have the effect of decreasing effective collisions making the reaction slow down.
    Converting the iron to a powder makes it an ionic compound which reacts more rapidly.  - False - Converting to a powder is a physical change and does not change the chemical identity of the Fe).
    Smaller particles have a lower energy of activation than larger particles.  False - Activation energy is a function of Fe, not the size of the particles.
    Converting the iron to a powder makes it a catalyst.  - False - A catalyst is another substance added to the reaction which speeds up the reaction but is not used up in the reaction.