Sig Figs
5.23 cm Significant Digits (Sig Digs) 5.230 cm Significant Digits include: measured certain digits last estimated digit (uncertain) 5.23 cm do not overstate the precision 5.230 cm
Significant Digits 0.0003700400 m All nonzero digits are significant. Captive Zeroes between two significant digits are significant. Leading Zeroes at the beginning of a number are never significant. Trailing Zeroes are significant at the end of a number IF there is a decimal. 2. 3. 4. Captive 0’s Leading Exact numbers are infinitely significant. How many boy students in here? Plus girls? How many sig figs? Trailing How many sig digs? 200 (1) 200. (3)
+ & – x & ÷ Significant Digits 3.48 g + 2.2 g = 5.68 5.7 round answers to keep the fewest decimal places round answers to keep the fewest sig digs 3.48 g + 2.2 g = 5.68 5.7 x & ÷ 6.40 cm x 2.0 cm = 12.8 13
Quick Quiz! 1. How many sig digs are in each number? 250.0 mL 4.7 x 10–5 kg 34000000 mg 0.03400 m 4 2 2 4 2. Round the answer to the correct sig digs. (i) 34.5 m x 23.46 m (ii) 123 g ÷ 3 mL (iii) 23.888897 g + 11.2 g (iv) 3.00g – 2.0 g ÷ 4 cm3 809 m2 40 g/mL 35.1 g 0.3 g/cm3 1.0 g