CHE 106 Lecture Notes - Lecture 3: Metric System, Order Of Operations, Decimal Mark
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CHE 106 Full Course Notes
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Measurement: quantifying a physical quantity using a unit of measurement. Accuracy: how well a measured value agrees w the true or accepted value. Precision: how well measured values agree w each other when measured identically. Standard deviation: how individual measurements deviate from the average. Exact numbers: #s which are known with certainty. Inexact numbers: #s which are not known w certainty (measuring) All #s known w certainty are sig + one uncertain # Digital instruments: last digit is considered uncertain but still significant. Start by reading # from left to right & start counting sig figs at the first non zero # Zeros at the beginning of a # are not sig. 0. 6m (1 sig fig) 0. 00045s (2 sig fig) 6. 004n (4 sig fig) 7084 (4 sig fig) Zeroes at the end of a # are sig only if there"s a decimal point present. 65. 0 (3 sig fig) 6700 (2 sig fig) 517. 200 (7 sig fig)
