CHEM 6A Lecture Notes - Lecture 1: Scientific Notation, Chemical Formula, Scientific Method

• School: UCSD
• Department: Chemistry and Biochemistry
• Course: CHEM 6A
• Professor: Thomas Bussey

Document Summary

Chemistry is the study of matter and how it changes: known as the central science, relates to biology, physics, geology, etc. Three levels of observation: macroscopic, microscopic, sub-microscopic, chemists think on the latter two levels. Symbolic representation: chemical formula (h2o, electron dot figure (h:o:h, bond-line figure (h-o-h, ball-and-stick model (indicates atomic orientation, space-filling model (fills space to show electron fields, atomic orientation, electron-density model (same as above, but shows nuclei) Scientific method: there is no single scientific method. The law of conservation of mass: mass remains constant during a chemical reaction. Observation and measurement: qualitative: general characteristics of the material under study. Color, smell, shape: quantitative: results expressed as a number with units. Scientific notation: shorthand for very large or very small numbers. Units and measurements: 2 parts: number and unit, all measurements are made relative to a standard, all measurements have uncertainty. Measured numbers vs exact numbers: measured numbers have some uncertainty, exact numbers are infinitely significant.