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    Time in seconds: 10 20 30 40 50 60 70 80

    Volume of gas in cm3 (rock a): 19 32 43 50 56 59 60 60

    Volume of gas in cm3 (rock c): 25 40 50 55 60 60 60 60

    One of the rock samples was marble chips and the other was powdered chalk. Suggest which rock was powdered chalk. Explain your answer.

    Please help. Thanks for reading
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    How have you approached the question so far?
    You should see from the rates of reaction which was marble or powdered and then explain it.
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    (Original post by MezmorisedPotato)
    How have you approached the question so far?
    You should see from the rates of reaction which was marble or powdered and then explain it.
    I wrote: Rock C is powdered chalk as it reacts faster with hydrochloric acid because it has a bigger surface area
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    (Original post by EtienneWelch)
    I wrote: Rock C is powdered chalk as it reacts faster with hydrochloric acid because it has a bigger surface area
    yup.
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    (Original post by EtienneWelch)
    I wrote: Rock C is powdered chalk as it reacts faster with hydrochloric acid because it has a bigger surface area
    that seems right, maybe go into greater detail of why a larger surface area leads to a faster rate of reaction
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    (Original post by EtienneWelch)
    I wrote: Rock C is powdered chalk as it reacts faster with hydrochloric acid because it has a bigger surface area
    Yes, that is correct.
    If you want, you can do some calculations for rate by dividing the volume by time at each interval.
    Or do it graphically by drawing it, then drawing a tangent at different points, then working out its gradient.
    You can see it visually too as the maximum volume of 60cm3 is reached quicker on C than A. So mention that in your answer as well.
 
 
 
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