CHEM 1421 Chapter : Chapter 1 Notes
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Can be observed without changing a substance into another substance. Ex: boiling point, density, mass, volume, etc: chemical properties . Can only be observed when a substance is changed into another substance. These are changes in matter that do not change the composition of a substance. Ex: changes of state (s, l, g), temperature, volume, etc: chemical changes. Ch4 (g) + 2 o2 (g) co2 (g) + 2 h2o (g) The process of science and discovery: the word science is derived from a latin verb meaning to know. science is a creative (esp. chemistry!) cycle of discovery and analysis. Precision how closely the measurements agree with one another. Accuracy how close the measurement is to the true value. All the digits of the measured quantity, including the uncertain one (last number) are called significant figures. Example: 3. 45 (3 sig figs), 4. 3789999 (8 sig figs) What is tricky is how we treat zeros in a measured quantity.
