2. Introduction to Chemistry

3. What is Chemistry? The study of the composition of matter and the changes that matter undergoes The study of the composition of matter and the changes that matter undergoes

4. Five major branches of chemistry Organic Organic

5. Inorganic Inorganic

6. Analytical Analytical Physical Physical Biochemistry Biochemistry

7. Why study Chemistry??? Pure Chemistry Pure Chemistry Applied Chemistry (Technology) Applied Chemistry (Technology)

8. Chemistry plays a big part in our lives We are in the “Age of Plastics” We are in the “Age of Plastics” High “strength to weight” ratio High “strength to weight” ratio

9. Energy New fuels New fuels New insulation material New insulation material

10. Energy from the sun Energy from the sun Hydrogen cells Hydrogen cells Storage batteries Storage batteries

11. Medicine and Biotechnology Medicines Medicines Surgical breakthroughs Surgical breakthroughs Genetic research Genetic research

12. Agriculture Protect crops Protect crops Increase food supply Increase food supply Increase strength and vitality of plants Increase strength and vitality of plants

13. Environment Pollution Pollution Catalytic converters Catalytic converters Acid rain Acid rain Ozone layer Ozone layer

14. SCIENTIFIC METHOD

15. 1. Observation Gather data: qualitative or quantitative

16. 2. Hypothesis t tentative explanation for what is observed (educated guess)

17. 3. Experiments – set of controlled observations that test a hypothesis

18. –Independent variable – one you are going to change

19. –Dependent – changes depending on the independent variable

20. –control – standard for comparison –Model – visual, verbal and/or mathematical explanation of experimental data

21. Conclusion – judgment based on the information obtained – judgment based on the information obtained

22. Theory – explanation that has been supported by MANY experiments – explanation that has been supported by MANY experiments

23. Scientific Law – describes a relationship in nature that is supported by many experiments. – describes a relationship in nature that is supported by many experiments.

24. Types of observations Qualitative observations – describe a substance without using numbers “It is heavy” “ It is blue” “It smells”

25. Quantitative observations – use numbers 87 millimeters 10 liters 4.0 g/ml

26. Scientific Notation 765,000,000,000 7.65 X 10 11 Move decimal to the left – is positive 0.0000084 8.4 X 10 -6 Move decimal to the right – is negative Samples on handout

27. Write in standard notation 4.5 x 10 -5 0.000045 3.42 x 10 4 34200

28.  Is how close a measurement is to the correct or accepted value

29.  How close a series of measurements are to each other  (how close a measurement is to other measurements of the same thing)  Dartboard example

30.  Assures the certainty of measurements  For any measurement, scientists only record all the digits they are certain of, plus one estimated figure  Together, they are called “significant figures”

31.  6.2345 meters  All the digits are significant. Which one is the estimated and which are certain?  6,2,3,4 are certain  5 is estimated

32.  A scientist measures 89 seconds  All are significant  Which are certain and which are estimated?  8 is certain  9 is estimated

33.  Rule 1 – all nonzero digits are significant – 1,2,3,4,5,6,7,8,9 – are significant  Rule 2 – Final zeroes to the right of the decimal point are significant  3.4000 5 sig figs

34.  Rule 3 – zeroes between two significant digits are significant  304 3 sig figs  70009 5 sig figs

35.  Rule 4 – zeroes used for spacing the decimal point are not significant  0.00045 2 sig figs  0.02387 4 sig figs

36.  Rule 5 – for numbers in scientific notation, all of the digits before “x 10 x ” are significant  5.730 x 10 9 4 sig figs

37.  7000 1 sig fig  7000. 4 sig figs

38. Let’s practice!! 135.3 4 sig figs 4.6025 5 sig figs 200,035 6 sig figs 0.0000300 3 sig figs

39. 2.0000300 8 sig figs 0.002 1 sig fig 4.44 x 10 3 3 sig figs 2.0 x 10 -2 2 sig figs

40. 10.00 4 sig figs 10 1 sig fig 10. 2 sig figs 102,000 3 sig figs