Question

What do you understand by 'significant figures'? What are the rules for determining the number of significant figures? Illustrate with suitable examples.

Answer 1

• In chemistry, Significant figures are the digits of value that carry meaning towards the resolution of the measurement. They are also called significant figures in chemistry.

There are certain rules which need to be followed to measure the significant figures of a calculated measurement.

• Listed below are the basics of the law:

1. All non-zero digits are significant
2. Zeroes between non-zero digits are significant.
3. A trailing zero or final zero in the decimal portion only are significant.

• Following are the significant figures rules that govern the determination of significant figures:

1. Those digits which are non-zero are significant. For example, in 6575 cm there are four significant figures and in 0.543 there are three significant figures.
2. If any zero precedes the non-zero digit then it is not significant. The preceding zero indicates the location of the decimal point, in 0.005 there is only one and the number 0.00232 has 3 figures.
3. If there is a zero between two non-zero digits then it is also a significant figure. For example; 4.5006 have five significant figures.
4. Zeroes at the end or on the right side of the number are also significant. For example; 0.500 has three significant figures.
5. Counting the number of objects for example 5 bananas 10 oranges have infinite figures as these are inexact numbers.

• $$\text{Significant Figures Examples}$$

1. 4308 – 4 significant figures
2. 40.05 – 4 significant figures
3. 470,000 – 2 significant figures
4. 4.00 – 3 significant figures
5. 0.00500 – 3 significant figures