Significant figures are an important aspect of doing calculations in both chemistry and physics. Significant figures allow a reader to know how precise certain calculations are and how much of a variation there may be in an answer.<\/p>\n
First, we need to be able to identify how many significant figures are in a number. The rules for identifying\u00a0 the number of significant figures are:<\/p>\n
1) <\/strong>All non-zero digits are significant (123 has 3 significant figures).<\/p>\n 2) <\/strong>All zeroes between non-zero digits are significant (10203 has 5 significant figures).<\/p>\n 3)<\/strong> Leading zeroes are not significant (0.00123 has 3 significant figures).<\/p>\n 4)<\/strong> Trailing zeroes <\/strong>in a number containing a decimal point are significant. (150.00 has 5 significant figures)<\/p>\n 5)<\/strong> Trailing zeroes in a number not containing a decimal point are not significant (150 has 2 significant figures).<\/p>\n Note:<\/strong> Rule 5 is controversial and some teachers or professors will report that trailing zeroes in a number without a decimal point are significant. It may be helpful to clarify with your teacher or professor regarding rule 5.<\/p>\n Note: <\/strong>Scientific notation has the same rules as above. (1.50 x 102<\/sup> has 3 significant figures)<\/p>\n When adding or subtracting numbers, the result must have a certain number of decimal places. The number of decimal places is determined by the original quantity with the least number of decimal places and thus determines the equation’s accuracy.<\/p>\n Example:<\/p>\n 1.23 + 4.5678 + 9.0 = 14.8<\/p>\n This is because 9.0 has the least number of decimal places, which is one, and thus our answer can only contain one decimal place.<\/p>\n When multiplying or dividing numbers, the result must have a certain number of significant figures. The number of significant figures is determined by the original quantity with the least number of significant figures.<\/p>\n Example:<\/p>\n 2.00 x 4.351 = 8.70<\/p>\n This is because 2.00 has the last number of significant figures, and thus our answer can only contain three significant figures.<\/p>\nAddition and Subtraction<\/strong><\/h5>\n
Multiplication and Division<\/strong><\/h5>\n