ivy1994 Posted March 17, 2012 Report Share Posted March 17, 2012 Hi!So I'm just doing a lab write up at the moment and I'm up to an absolute uncertainty calculation...Absolute uncertainty calculation(3.13/100) x 24.406745 = 0.76393...Am I supposed to round this to 1 and then also round my reading of 24.406745 to 3 sf? So it would be.... 24.4 ± 1 kJmol-1 ??Thanks in advance!! Reply Link to post Share on other sites More sharing options...
timtamboy63 Posted March 17, 2012 Report Share Posted March 17, 2012 Why round it to one? Make sure it has the same number of d.p as your answer. Eg 35.15 +- 0.23 or 35.1 +- 0.2 (I'm just using random numbers here) Reply Link to post Share on other sites More sharing options...
dessskris Posted March 17, 2012 Report Share Posted March 17, 2012 in chemistry, no of decimal place of unc follows no of decimal place of data. no of sig fig of (processed) data follows the least no of sig fig of any data in the working.for example:mass=concentration*volumemass=0.10*0.200mass=0.020 g (2sf because conc has 2sf and vol has 3sf)%unc of mass=%unc of conc + %unc of vol%unc of mass=0% + 0.005/0.200 *100%%unc of mass=2.5%unc of mass=2.5%*0.020unc of mass=0.0005gunc of mass=0.001gmass=(0.020+/-0.001) g Reply Link to post Share on other sites More sharing options...
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