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CHEMISTRY

In this chemistry lesson, we delve into an intriguing brain teaser involving a dollar bill, ethanol, and fire. What happens when we dip a dollar bill in a 50% ethanol solution and ignite it? Predict your results and observe the fascinating chemical reactions. Additionally, we explore the essential concepts of chemistry, including SI units, significant figures, and measurement accuracy. Discover why understanding these principles is crucial for scientific inquiry and accurate data reporting. Join us for a journey through the foundational aspects of chemistry!

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CHEMISTRY

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  1. CHEMISTRY July 31st, 2012

  2. Brain Teaser: Dollar Bill 2 • What do think will happen if I dip a dollar bill in a 50% ethanol solution and light it on fire? Why? • Demo • Record Observations • Was your prediction correct? • Explain the science behind this

  3. Agenda 3 • Brain Teaser • Demo: Dollar Bill • Lecture: • Introduction to Chemistry • SI Units and Base Units • Significant Figures • Homework • Intro to Measurement Worksheet

  4. Unit 1 ObjectivesIntroduction to Chemistry 4 • Define chemistry and matter • Units of measurement • SI Units • Base Units • Accuracy versus Precision • Uncertainty in Measurement • Significant Figures

  5. Chemistry is the science that investigates and explains the structure and properties of matter. • Seeks to explain the submicroscopic events that lead to macroscopic observations Introduction to Chemistry 5 • Chemistry: The Central Science

  6. Branches of Chemistry 6

  7. SI Units (Le Systéme Internationale) Units of measurement 7 • Scientists need to report data that can be reproduced by other scientists. They need standard units of measurement. Base Units • A base unit is a defined unit in a system of measurement • There are seven base units in SI.

  8. Base Units 8

  9. 9

  10. SIGNIFICANT FIGURES 10

  11. Digits in a measurement that have meaning relative to the equipment being used Significant Figures 11 • Significant Figures

  12. What is the increment on the equipment? What you know for sure. Significant Figures 12 • Place

  13. Digits that can be known precisely plus a last digit that must be estimated. Significant Figures 13 • Digits with meaning

  14. 14

  15. Ruler 15 • http://www.funbrain.com/measure/ • What are the units?

  16. Graduated Cylinder 16 • http://www.uwplatt.edu/chemep/chem/chemscape/labdocs/catofp/measurea/volume/gradcyl/gradcyl.htm • What are the units?

  17. Depends on type of equipment being used. Depends on size of equipment used. Significant Figures 17 • What do you notice?

  18. All digits 1-9 are significant. • Zeros between significant digits are always significant. • Trailing 0’s are significant only if the number contains a decimal point • Zeros in the beginning of a number with a decimal point are not significant. • Zeros following a significant number with a decimal are significant. Significant Figures 18 • Raw Data Rules • How do you know how many sig figs?

  19. Pacific = Decimal Present Start from the Pacific (left hand side), every digit beginning with the first 1-9 integer is significant 20.0 = 3 sig digits 0.00320400 = 6 sig digits 1000. = 4 sig digits Significant Figures 19 • Pacific to Atlantic Rule • Examples

  20. Atlantic = Decimal Absent Start from the Atlantic (right hand side), every digit beginning with the first 1-9 integer is significant 100020 = 5 sig digits 1000 = 1 sig digits Significant Figures 20 • Atlantic Rule to Pacific • Examples

  21. Practice 21 • How many significant figures are in • 400.0 • 4000 • 4004 • 0.004

  22. Rally Rows 22 How many significant figures are in • 0.02 • 0.020 • 501 • 501.0 • 5000 • 5000. • 5050 • 01.0050 • 50300 • 5.0300

  23. Review Questions 23 • Determine the number of significant figures in the following: • 1005000 • 1.005 • 0.000125 • 1000. • 0.02002 • 2002 • 200.200

  24. Review Questions 24 Determine the number of significant figures in: • 72.3 g • 60.5 g • 6.20 g • 0.0253 g • 4320 g • 0.00040230 g • 4.05 x 10^5 g • 4500. g

  25. Why do we use the metric system? 25 • Advantages • Simple to use • Easy to convert from one unit to another • Dimensional Analysis • Universal – used worldwide • By all scientists to communicate • By all industrialized nations • Except United States • U.S. loses billions of dollars in trade

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