CHEM105 Lecture Notes - Lecture 13: Significant Figures, Leading Zero, Decimal Mark
Document Summary
Quantitative (measurement with a number and a scale) Accuracy, agreement of a particular value with the true value. Precision how close all the measurement numbers are to each other. Degree of agreement among several measurements of the same quantity. The more precise the scientists, the more accurate the measurement. A digit that must be estimated is called uncertain. Record the certain digits and the first uncertain digit (the estimated number) Significant figures tell us the uncertainty in a measurement. Include all certain digits + the first uncertain digit. Meniscus (bottom of liquid curve) of the liquid occurs at the bottom at about 20. 15ml. Uncertain digit: 20. 1(5) (last digit is always uncertain. ) How do you count sig figures: a number that is not zero is always significant, there are three classes of zeros, leading zeroes are zeros that precede all the non-zero digits. 0. 048 has 2 significant figures: captive zeroes are zeroes between nonzero digits.
