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Chem1 2015 June aqa AS-chemistry, past paper quesiton help

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(edited 5 years ago)
Original post by OrbitalMelon
Hiya! Can anybody explain to me why on question 7)b) (Ideal Gas equation question) the 4.4 is multiplied by 2/3 in the mark scheme? Other than that I did all the conversions and re-arranging etc correct except I used the 4.4 value straight off which then gave an incorrect mass.


http://filestore.aqa.org.uk/subjects/AQA-CHEM1-QP-JUN15.PDF
and markscheme:
http://filestore.aqa.org.uk/subjects/AQA-CHEM1-W-MS-JUN15.PDF


In the equation you can see that the mole ratio of nitrogen to sodium azide is 3:2, so if you have the moles of nitrogen you must multiply by 2/3 to get the moles of sodium azide.

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