Search results
Chemistry: Significant Digits. 1. Significant numbers are always measurements and thus should always be accompanied by the measurement's unit. For simplicity, units are not included in the following examples. 2. Any numbers (that are measurements) other than zero are significant. (Many times the zeros are also significant as you will see below.)
The following rules apply to calculations with significant figures: Exact physical and mathematical constants and defined conversion factors (π, 1 inch = 2.54cm, 1kg = 1000g) and integer coefficients (like the 2 in “2πr”) have an infinite. number of significant figures.
Rules for deciding the number of significant figures in a measured quantity: All nonzero digits are significant: 1.234 g has 4 significant figures, 1.2 g has 2 significant figures. Zeroes between nonzero digits are significant: 1002 kg has 4 significant figures, 3.07 mL has 3 significant figures.
Any number used in a calculation should contain only figures that are considered reliable; otherwise, time and effort are wasted. Figures that are considered reliable are called significant figures. Chemical calculations involve numbers representing actual measurements.
How are significant figures handled in calculations? It depends on what type of calculation is being performed. If the calculation is an addition or a subtraction, the rule is as follows: limit the reported answer to the rightmost column that all numbers have significant figures in common.
7. Apply guidelines on reporting significant figures in graph interpretation. 8. Use significant figures as a quality control objective. 9. Aspire to improve the quality of scientific meaning and decision making by properly determining, reporting, and interpreting significant figures in measurements and their calculated values. 10.
BASIC RULES FOR SIGNIFICANT FIGURES. This is just a summary of the rules for significant figures. For deeper explanations, more examples, and extra practice with these rules, please see the “Significant figures review” from the course website.
