1. Data Analysis Applying Mathematical Concepts to Chemistry

2. Scientific Notation  concise format for representing extremely large or small numbers  Requires 2 parts: Number between 1 and 9.99999999… Power of ten Examples:  6.02 x 10 23 = 602,000,000,000,000,000,000,000  2.0 x 10 -7 m = 0.0000002 m Use calculator to solve problems on p. 788-789

3. Accuracy vs Precision  Accuracy- closeness of measurements to the target value Error- difference between measured value and accepted value (absolute value)  Precision- closeness of measurements to each other

4. Percent Error  %error = (accepted-experimental) x 100 accepted  EX: The measured mass is 5.0g. It was predicted that the accepted value should have been 6.0 g.  % error = 6.0g-5.0g x 100 = 16.7% 6.0g

5. Significant Figures  Measurements are limited in their sensitivity by the instrument used to measure

6. Estimating Measurements  Read one place past the instrument  35.0 mL is saying the actual measurement is between 34.9 and 35.1 mL

7. Why Significant Figures?  Measurements involve rounding  Multiplying/dividing or adding/subtracting measurements can not make them more accurate  Provide a way to tell how sensitive a measurement really is…  5 ≠ 5.0 ≠ 5.00 ≠ 5.000

9. Recognizing Significant Digits  1. Nonzero digits are always significant 543.21 meters has 5 significant figures  2. Zeros between nonzeros are significant 505.05 liters has 5 sig figs  3. Zeros to the right of a decimal and a nonzero are significant 3.10 has 3 sig figs

10. Recognizing Sig Figs  4. Placeholder zeros are not significant 0.01g has one sig fig 1000g has one sig fig 1000.g has four sig figs 1000.0g has five sig figs  5. Counting numbers and constants have infinite significant figures 5 people has infinite sig figs

11. Rule for Multiplying/Dividing Sig Figs  Multiply as usual in calculator  Write answer  Round answer to same number of sig figs as the lowest original operator  EX: 1000 x 123.456 = 123456 = 100000  EX: 1000. x 123.456 = 123456 = 123500

12. Practice Multiplying/Dividing  50.20 x 1.500  0.412 x 230  1.2x10 8 / 2.4 x 10 -7  50400 / 61321

13. Rule for Adding/Subtracting  Round answer to least “precise” original operator.  EX: 1000 + 1.2345 1000

14. Practice Adding/Subtracting  100.23 + 56.1 .000954 + 5.0542  1.0 x 10 3 + 5.02 x 10 4  1.0045 – 0.0250

15. Units of Measure  SI Units- scientifically accepted units of measure: Know:  Length  Volume (m 3 )  Mass  Density (g/mL)  Temperature  Time

16. The Metric System

17. Metric Practice  623.19 hL = __________ L  1026 mm = ___________cm  0.025 kg = ___________mg  Online Powers of 10 Demonstration: http://micro.magnet.fsu.edu/primer/java/sci enceopticsu/powersof10/

18. Good Info to Know  Volume- amount of space an object takes up (ex: liters)  V = l x w x h  1 cm 3 = 1 mL by definition

19. More Good Info to Know  Mass is different from weight  Mass ≠ Weight  Mass= measure of the amount of matter in an object  Weight= force caused by the pull of gravity on an object ***Mass is constant while weight varies depending on the location of an object***

20. Temperature Scales

21. Temperature Conversions  Degrees Celsius to Kelvin  T kelvin =T celsius + 273  EX: 25 °C = ? K  T kelvin =25 +273=298K  Kelvin to Degrees Celsius  T celsius =T kelvin - 273  EX: 210 K = ? °C  T c = 273–210= -63°C

22. Derived Quantities- Density  Density- how much matter is in the volume an object takes up.  Density = mass/volume  D= g/mL

23. Determining Density  Mass- measure in grams with balance  Volume- Regular shaped object: measure sides and use volume formula  EX: rectangle  V= l x w x h Irregular shaped object: water displacement

24. Density by Water Displacement  Fill graduated cylinder to known initial volume  Add object  Record final volume  Subtract initial volume from final volume  Record volume of object

25. Graphing Data  General Rules Fit page Even scale Best fit/trendline Informative Title Labeled Axes How Does Volume Impact Temperature?