CH110 Foundations of GENERAL, ORGANIC, & BIOCHEMISTRY CHEMEKETA COMMUNITY COLLEGE

1. CH110 • Foundations of • GENERAL, ORGANIC, • & BIOCHEMISTRY • CHEMEKETA COMMUNITY COLLEGE • INSTRUCTOR: Larry Emme

2. 1st Day Stuff • Who are you? Are you in the right place? • GOB • CTV Introduction • Privacy waver • Course Syllabus & requirements • Who am I?

3. Prologue P.2 Scientific Method: Thinking like a Scientist

4. Scientific Method The scientific method is the process used by scientists to explain observations in nature.

5. Scientific Method The scientific method involves Making Observations Writing a Hypothesis Doing Experiments Proposing a Theory

6. Features of the Scientific Method Observations Facts obtained by observing and measuring events in nature. Hypothesis A statement that explains the observations. Experiments Procedures that test the hypothesis. Theory A model that describes how the observations occur using experimental results.

7. Summary of the Scientific Method

8. Major divisions of Chemistry Elements besides Carbon Methods of analysis Theory and concepts Carbon based compounds Chemistry of living things • General • Inorganic • Analytical • Physical • Organic • Biochemistry

9. Chapter 1:Measurement • Units of Measurement • Significant Figures • Conversion Calculations • Density

10. Measurements in chemistry • See Handout Sheet of • Units of Measurements

11. Units of Measurement meter (m) 1 m = 1.09 yd liter (L) 1 L = 1.06 qt gram (g) 1 kg = 2.2 lb

12. Matter • =The stuff things are made of. • (Air, water, rocks, etc..) • Matter has Mass and takes up space. • =The amount of stuff (in g’s) • (Bowling Ball > Balloon) Weight on earth. =Pull of Gravity on matter.

13. Mass Vs. Weight How much would you weigh on another planet? http://www.exploratorium.edu/ronh/weight/

14. Scientific notation • If a number is larger than 1 • Move decimal point X places left to get a number between 1 and 10. 1 2 3 , 0 0 0 , 0 0 0. = 1.23 x 108 • The resulting number is multiplied by 10X.

15. Scientific notation • If a number is smaller than 1 • Move decimal point X places right to get a number between 1 and 10. 0. 0 0 0 0 0 0 1 2 3 = 1.23 x 10-7 • The resulting number is multiplied by 10-X.

16. Examples • Write in Scientific Notation: • 25 = • 8931.5 = • 0.000593 = • 0.0000004 = • 3,210. = 2.5  10 1 8.9315  10 3 5.93  10 - 4 4  10 - 7 3.210  103 Do not press this on your calculator!

17. Scientific notation 0.0144939 • 1.44939 × 10-2 = 1.44939E -2 On Calculator 1.44939 (-) 2 EE ×10 Means ×10 Change Sign

18. Measured & Exact Numbers • Exact Numbers = • from counting or by definition 12 coins per package 12 coins 1 package 1 package 12 coins = 12 coins 1 dozen coins 1 dozen coins 12 coins =

19. Measured & Exact Numbers • Measured Numbers = • estimated using a tool All measurements contain some uncertainty. • We make errors • Tools have limits

20. Accuracy Precision • How close are we to the true value? • Truth • How well do our values agree? • Consistency

21. Significant figures Length of object is between 6.7 and 6.8 The next digit would be a guess.             If use 6.76 then have error of + 0.01cm

22. Certain Digits Uncertain Digit Significant figures • Expresses accuracy & precision. • You can’t report numbers better than the method used to measure them. • 6.76 units = 3sig figures

23. Significant figures • Sig Figs don’t depend on the decimal point. • 255 millimeters • 25.5 centimeters • 2.55 decimeters • 0.255 meters • 0.0255 decameters 3 Sig Figs

24. Significant figures: Rules for zeros Leading zeros are notsignificant. 0.00421 3 sig figs Leading zero Captive zeros are significant. 4012 4 sig figs Captive zero Trailing zeros behind decimal are significant. 114.20 5 sig figs Trailing zero

25. 32,000 or 3.2 x 104 32000 or 3.20 x 104 32000 or3.200 x 104 32000 or3.2000 x 104 32000. _ _ _ Significant figures: Rules for zeros • 32,000 • Are the 0’s significant? • 2 sig figs = • 3 sig figs = • 4 sig figs = • 5 sig figs =

26. Significant figures: Rules for zeros • 1025 km • 2.00 mg • 0.00570 • 520 Four(Captive zeros are significant) Three(trailing zeros behind decimal are significant) Three(only trailing zero behind decimal is significant, leading zeros are not) Two(No decimal, zero assumed insignif)

27. Rounding Write with 4 Significant Figures: 2.5795035 becomes 2.580 > 5 round up < 5 round down. 1st insignificant digit 34.204221 becomes 34.20

28. Significant figuresand calculations • An answer can’t have greater significance than the quantities used to produce it. • Example • How fast did you run if you • went 1.0 km in 3.00 minutes? 0.3333333333 speed = 1.0 km 3.00 min = ?

29. Simplified rules for significant figures • Multiplication & Division Problems: • Do calculations. speed = 1.0 km 3.00 min = 0.333333333 km min • Look at sig figs for each value in calculation. (Constants don’t count.) 3 sig figs 2 sig figs • Report answer with same sig figs as least significant value. = 0.33 km min • Round off as needed.

30. Simplified rules for significant figures • Addition & Subtraction Problems: • Do calculations. Significant to .1 1.9 + 18.65 20.55 Significant to .01 • Look at least significant place for each value in calculation. • Report answer to least significant place. = 20.6 Significant to .1 • Round off as needed.

31. Metric prefixes • Changing the prefix alters the size of a unit. • Prefix Symbol Factor (multiple) mega M 106 1,000,000 kilo k 103 1,000 deci d 10-1 0.1 centi c 10-2 0.01 milli m 10-3 0.001 100 1

32. Problem Solving Using Conversion Factors • Many problems require a change of one unit to another unit by using conversion factors (fractions). unit1× conversion factor = unit2

33. It must cancel inches. It must introduce feet How many feet are there in 22.5 inches? The conversion factor must accomplish two things: unit1× conversion factor = unit2 inches × conversion factor = feet

34. The conversion factor takes a fractional form.

35. Putting in the measured value and the ratio of feet to inches produces:

36. Convert 3.7×1015 inches to miles. Inches can be converted to miles by writing down conversion factors in succession. in  ft miles

37. Convert 4.51030 cm to kilometers. Centimeters can be converted to kilometers by writing down conversion factors in succession. cm  m km

38. Conversion of units • Examples: 10.7 T = ? fl oz 62.04 mi = ? in 5 kg = ? mg 9.3 ft = ? cm 5.7 g/ml = ? lbs/qt

39. Density Mass Density = Volume • Water 1.0 Urine 1.01 - 1.03 • Air 0.0013 Bone 1.7 - 2.0 • Gold 19.3 Oil 0.8 - 0.9 1cc = 1 cm3 = 1 ml = 1 g water g cm3 g ml At 4 o C or

40. Density calculation What is the density of 5.00 ml of serum if it has a mass of 5.230 g? • d =m • V • V =m • d • m = V d d =5.230 g 5.00 ml • = 1.05 g • ml

41. Specific gravity density of substance g ml • Specific Gravity = density of reference g ml Reference commonly water at 4oC • Specific Gravity is unitless. • At 4oC, density = specific gravity.

42. Specific gravity Hydrometer • Commonly used to test sugar in urine. • Float height will be • based on Specific Gravity.

43. Density as a Conversion A liquid sample with a density of 1.09 g/mL is found to weigh 7.453 grams. What is the volume of the liquid in mLs? • Identify any conversion factors. • What is unique to the problem? 7.453 g 1.0 ml 1.09 g = ml 6.837614 = 6.84 ml • How should the answer look? 1.09 g 1 ml 1 ml 1.09 g