Chem 15 | Chemistry for Engineers Lecture 1: Chemistry and Engineering “All engineering designs involve MATTER” Chem 15 | Chemistry for Engineers Chemistry? The study of MATTER: - its composition - changes that matter undergoes Matter is anything that occupies space and has mass. “Therefore, MATTER is EVERYTHING around us!” Chem 15 | Chemistry for Engineers Why study chemistry? Chemistry is the CENTRAL SCIENCE |Biochemistry |Energy The flash of the firefly results from a chemical reaction in the insect Solar panels are composed of specially treated silicon |Technology |Medicine LEDs (light emitting diodes) are formed from elements such as gallium, arsenic, and phosphorus Connectors and tubing for medical procedures such as intravenous injections are made from plastics highly resistant to chemical attack Chem 15 | Chemistry for Engineers 3 Levels in Understanding Chemistry 1. The Macroscopic Perspective Chem 15 | Chemistry for Engineers 3 Levels in Understanding Chemistry 1. The Macroscopic Perspective: Chem 15 | Chemistry for Engineers 1. The Macroscopic Perspective: physical and chemical properties Chem 15 | Chemistry for Engineers Physical or Chemical change? Chem 15 | Chemistry for Engineers 3 Levels in Understanding Chemistry 2. The Microscopic/Particulate Perspective: ATOM ELEMENTS Chem 15 | Chemistry for Engineers Chem 15 | Chemistry for Engineers 3 Levels in Understanding Chemistry 3. Symbolic Representation: Using chemical formulas and structures Chemical Formula Chem 15 | Chemistry for Engineers Chemical Structure Scientific Method Chem 15 | Chemistry for Engineers Precision and Accuracy Precision - how closely individual measurements to agree with one another Accuracy - how closely individual measurements agree with the correct “true” value Chem 15 | Chemistry for Engineers Numbers and Measurements Chem 15 | Chemistry for Engineers Chem 15 | Chemistry for Engineers Temperature Scales Chem 15 | Chemistry for Engineers Significant Figures - refers to digits that were measured When rounding calculated numbers, we pay attention to significant figures so we do not overstate the accuracy of our answers. Chem 15 | Chemistry for Engineers Significant Figures 1. All non-zero number is significant. 2. Zeros between non-zero numbers are significant. 3. Zeros before a non-zero number (with or without a decimal) is not significant. 4. Zeros after a non-zero numbers in a decimal is significant. 5. Zeros after a non-zero without decimal points MAY or MAY NOT be significant. Chem 15 | Chemistry for Engineers Dimensional Analysis Units are multiplied together or divided into each other along with the numerical values. Keep track of both numerical values and units. Chem 15 | Chemistry for Engineers Conversions The density of Ti is 4.50 g/cm3. What is the volume of 7.20 g Ti? Chem 15 | Chemistry for Engineers Using Unit Conversions Express a volume of 1.250 L in mL, cm3, and m3. Chem 15 | Chemistry for Engineers Chem 15 | Chemistry for Engineers