Stupid Significant Figures Question

[casbanjo]

I know you must use the same number of significant figures as the least accurate experimental data in your FINAL answer.

But do I also round of the results of calculations that are NOT the final calculation? Or do I use the maximum number of sig figs?

For example:

n(CH3OH) reacting = 0.934 ÷ 32.0
= 0.0292 mol  <------ this is actually 0.0291875
Energy released by methanol = CC × T
= 2.39 × 8.63
= 20.6 kJ
Energy from 1 mol CH3OH = 20.6 ÷ 0.0292 here i used 0.0291875 instead of 0.0292
= 706 kJ Which gave me 707 kJ instead of 706 kJ

Was VCAA correct in using the 0.0292 value for this?

[Bronzebottom64]

*Quote VCAA

SECTION B
Instructions for Section B
Answer all questions in the spaces provided. Write using black or blue pen.
To obtain full marks for your responses, you should:
• give simplified answers, with an appropriate number of significant figures, to all numerical questions;
unsimplified answers will not be given full marks.

From this one would assume to all answers not just the final answers.

And your title; All significant figures questions are stupid. 

[speedy]

2010 Exam 2 Assesors report:

[Yacoubb]

I know you must use the same number of significant figures as the least accurate experimental data in your FINAL answer.

But do I also round of the results of calculations that are NOT the final calculation? Or do I use the maximum number of sig figs?

For example:

n(CH3OH) reacting = 0.934 ÷ 32.0
= 0.0292 mol  <------ this is actually 0.0291875
Energy released by methanol = CC × T
= 2.39 × 8.63
= 20.6 kJ
Energy from 1 mol CH3OH = 20.6 ÷ 0.0292 here i used 0.0291875 instead of 0.0292
= 706 kJ Which gave me 707 kJ instead of 706 kJ

Was VCAA correct in using the 0.0292 value for this?

I've heard this from many assessors & it's really the most logical approach, to use unrounded figures in your calculations (i.e. never round off in the midst of calculations) and then provide your final answer to the correct number of significant figures.

[casbanjo]

I've heard this from many assessors & it's really the most logical approach, to use unrounded figures in your calculations (i.e. never round off in the midst of calculations) and then provide your final answer to the correct number of significant figures.

That's what I did, so is VCAA wrong in this case then?

[Valyria]

Since we are on the topic of sig figs;

If the stem of the question preceding the parts of the question contains information to 2 significant figures and part (a) contains additional information with 3 significant figures, does our answer have to be to 2 or 3 significant figures?