What are significant figures in chemistry?

Chemistry : Significant figures Homework Help !!!!!!?

• I have a homework question in chemistry that says: Perform the following calculations and express the answers using the correct number of significant figures a) 0.8102 m x 3.44 m b) 94.20g -------------------- 3.167 22 mL c)32.89 g + 14.21 g d)34.09 L - 1.230 L

• Answer:

  Computations cannot improve the precision of the measurement. To add measures, they should all be rounded to the unit of the least precise measurement. The sum 8.6 cm + 0.14 cm + 2.75 cm is found by rounding each to tenths: 8.6 cm + 0.1 cm + 2.8 cm = 11.5 cm. Even by doing this, the absolute error might be as large as 0.05 + 0.005 + 0.005 or 0.06, and affect the result by as much as 0.1. In multiplying and dividing approximate numbers, the product or quotient is rounded to the number of significant digits in the number with the fewest significant digits. For example, 6.2 m × 8.75 m by computation is 54.25. The product needs to be rounded to 54 m2 so as to show two significant digits. a) 0.8102 m x 3.44 m b) 94.20g -------------------- 3.167 22 mL I don't understand this issue. c)32.89 g + 14.21 g, round each to tenths: 32.8 + 14.2 = 47 g d)34.09 L - 1.230 L, 1.230 = 1.23; round each to tenths: 34 - 1.2 = 32.8 L Bye from Italy, C6H6