ROUNDED OR UNROUNDED

[ngabe]

Hi,

My understanding of sig figs is that you don't have to worry about it until your final answer.

So let's say my final answer to part a is 1.23456 and let's say we're req to round it to 3sf. So my answer is 1.23.

In the event when we need part a to do part b, do we use the unrounded value or the rounded value?

My teacher always tell me to use the unrounded value (value on the cal) and work from there so it's more accurate but now that I did that, I've been getting some different answers from vcaa. eg my answer is 1.20, their answer is 1.19 kinda thing.

So, to use unrounded or rounded values in subsequent parts/questions?

Thanks a lot!

[brightsky]

use the unrounded value. always better to be more exact. the chief examiner's pretty lazy sometimes. so if your answer differs by 0.01 I won't be too concerned. your answer is probably more correct. but in general, the chem exam is written so that even if students use the rounded value, they will still arrive at the same answer. (unlike in maths, where the choice of decimal places and sig figs is quite random, in chem it's quite specific. some questions only require you to express it to like 2 sig figs because of the potential discrepancy that can arise.)