Rules concerning significant figures (1 Viewer)

[~ ReNcH ~]

In the exam, they don't usually specify the number of significant figures required for calculations. However, what are the rules concerning the number of significant figures to be used? Would you be marked down in the HSC exam if you rounded to an "incorrect" number of significant figures, such as writing 1.22 (3 s.f.) when the scientifically correct answer was actually 1.2 (2 s.f.)?

 

[Sepulchres]

As far as i know and have been told, you dont round during your calulations, but do so at the end. There isnt a standard significant number but as long as you state the number of d.p or s.f, you should be fine.

 

[Dreamerish*~]

Usually 2 or 3 decimal points is okay, as long as you write (2 d.p) or (3 d.p), but as Sepulchres said, don't round off during calculations.

However, there is a rule for converting between H⁺ and pH. The number of decimal places in the value for pH should equal the number of significant figures in the value for H⁺.

 

[~ ReNcH ~]

Ok...coz I was reading through the 2004 Marking Guidelines and they made a statement at the beginning of the document about the fact that students should learn the rules concerning significant figures and how to use them properly. Whether that referred simply to the number of s.f. that should be used or to confusion over when 0s are and aren't to be included, I wasn't too sure.

 

[Dreamerish*~]

Ok...coz I was reading through the 2004 Marking Guidelines and they made a statement at the beginning of the document about the fact that students should learn the rules concerning significant figures and how to use them properly. Whether that referred simply to the number of s.f. that should be used or to confusion over when 0s are and aren't to be included, I wasn't too sure.

It's probably the latter.

 

[Jumbo Cactuar]

The number of significant figures should match the least number of significant figures in the data given.

 

[~ ReNcH ~]

The number of significant figures should match the least number of significant figures in the data given.

So if you had 150mL of water and 1g of salt, in finding the salt concentration you'd round it to 1 s.f.?