Answer to Question #68537 in General Chemistry for Allison Marie Medina

Question

How do you count significant figures?

Answer 1

You should remember that in chemistry all numbers are based upon measurements. All measurements are different and we need use those numbers that are meaningful.
There are three rules on counting of amount of significant figures are in a number:
Any zeros between two significant digits are significant.
As a good example are 908, 19.5603, 1903.05, etc.
Non-zero digits are always significant.
A number like 5.898 would have four significant figures and 1.11 would have three.
A final zero or trailing zeros in the decimal portion only are significant.
So, zero after decimal portion is not significant like in case 0.002763000, last three zeroes are not significant, that is why this number have got 7 significant figures.