160 likes | 295 Views
SI Base Units. SI Base Units. Prefixes to Memorize. Significant Digits Significant Figures. You will be asked to round to 3 significant figures But first you must know how to determine whether a number is considered significant. Rule 1. 1. All digits 1-9 are significant 789
E N D
You will be asked to round to 3 significant figures But first you must know how to determine whether a number is considered significant
Rule 1 • 1. All digits 1-9 are significant • 789 • 3 sig figs • 12587 • 5 sig figs • 1.234 • 4 sig figs
Rule 2 ~ BETWEEN • Any zero between two significant digits is automatically significant • 1003 • 4 sig figs • 10.03 • 4 sig figs • 1,000,007 • 7 sig figs
Rule 3 ~ FINAL ZERO • Any FINAL ZERO (after the decimal point) is significant. • 12.30 • 4 sig figs • 3.5768000 • 8 sig figs • 4.0 • 2 sig figs
Any zero is insignificant if it is not between two sig digits nor the final zero after a decimal point. Theses zeros are called placeholders. Rule 4 ~ placeholder • 400 • 1 sig fig • 10000 • 1 sig fig • 789,600 • 4 sig figs • 0.00059 • 2 sig figs • 0.000590 • 3 sig figs
Examples • 30040 grams • 4 sig figs • The last zero is not significant
0.663 kg • 3 sig figs • The zero only located the decimal point and is not significant
20.05 L • 4 sig figs
1500 mg • 4 sig figs • There is line over the final zero, so all digits are significant
0.0008 grams • 1 sig fig • The zeros are only place holders. They are not significant
The End • Let’s practice!