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aqa mark scheme query!

So i deduced the mr of a compound by dividing mass by no.of moles... the number of moles was in standard form and the mr i deduced was also in standard form (1.17 x 10-3) however looking at the mark scheme it says 117.7 so would i be penalised??

thanks

Reply 1

EierVonSatan

1.17 x 10^-3 would be penalised

1.177 x 10² wouldn't

Reply 2

hamish123

EierVonSatan

1.17 x 10^-3 would be penalised

1.177 x 10³ wouldn't

thanks!

now i have another query lol

question gives values of 1.00 x 10(5) Pa, 352 cm3 volume, 8.31 and 298 K to work out number of moles using ideal gas equation

yet in the answer it reads.... 1.00 x 10(5) x 352 x (10-6) where does this 10 to the power of minus 6 appear from!?

Reply 3

EierVonSatan

firstly see my edited post above - it was mean't to be to the power 2 not 3

it looks like they're dividing by 1000 to convert cm³ into dm³ and dividing by 1000 to convert Pa into kPa, so dividing by 100,000 or mulitplying by 10^-6

Reply 4

hamish123