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    This question was a part of paper 31 of Nov 2014

    The helium in the cylinder has a volume of 6.0 × 10^–3 m3 (0.0060 m3) and is at a pressure of2.75 × 10^6 Pa.(i) The pressure of helium in each balloon is 1.1 × 10^5 Pa. The volume of helium in an inflatedballoon is 3.0 × 10^–3 (0.0030 m3). The temperature of the helium does not change.Calculate the number of balloons that were inflated.

    Here is the ans in the marking scheme.
    p1V1 = p2V2
    (V2 =) 2.75 × 10^6 × 6 × 10^–3/ 1.1 × 10^5 = 0.15 m3
    (no. of balloons = (0.15 – 6 × 10–3) / 3 × 10–3 =) 48

    In the last part they subtract the cylinder volume from the total volume. How do you know there is still helium left in the cylinder? The question does not mention anything about this
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    In the first part you calculate how many balloons you CAN fill with the helium in the canister, you don't use all the helium.
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    (Original post by Username002)
    In the first part you calculate how many balloons you CAN fill with the helium in the canister, you don't use all the helium.
    Thank you for the reply. How do you know if they didnt use all of the helium inside the cannister? They could have right? Sorry, my knowledge on this topic is a little rusty.
 
 
 
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