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Significant figures in chemistry calculations (1 Viewer)

cuppy

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how many significant figures are we expected to use in calculations?

and do we only have to have the final answer in significant figures or do all of our progressive calculations have to be in significant figures too?

because while doing some of the tutorial problems i noticed that i only got the exact answer given in the solutions if i held off using significant figures til the final answer. if i rounded them earlier (e.g. finding the number of moles of X then using this to find the concentration of an unknown solution) the answer i got was a bit off.

so what i did was round all intermediate calculations to about 4 decimal places then used them to obtain the final answer which i then expressed in significant figures (and this turned out to be the 'right' answer provided in the booklet)

so would this matter much in an exam? - like how flexible are they when it comes to having the precise answer?
 

jemsta

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i think they are fairly strict when it comes to rounding off the correct number of s.f
but if i remember correctly, it would be wise to round off to the correct significant figures once you get the correct answer
 

withoutaface

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cuppy said:
how many significant figures are we expected to use in calculations?

and do we only have to have the final answer in significant figures or do all of our progressive calculations have to be in significant figures too?

because while doing some of the tutorial problems i noticed that i only got the exact answer given in the solutions if i held off using significant figures til the final answer. if i rounded them earlier (e.g. finding the number of moles of X then using this to find the concentration of an unknown solution) the answer i got was a bit off.

so what i did was round all intermediate calculations to about 4 decimal places then used them to obtain the final answer which i then expressed in significant figures (and this turned out to be the 'right' answer provided in the booklet)

so would this matter much in an exam? - like how flexible are they when it comes to having the precise answer?
Be safe, use 8 s.f. then round off at the end.
 

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