1. INTRODUCTION TO CHEMISTRY
Chapter One
INTRODUCTION TO CHEMISTRY
“CHEMISTRY IS THE SCIENCE OF CHANGE. It looks at all the different kinds of substances and how they interact with each other. It is going on all around us all the time, as well as in the scientific laboratory and in the chemical industry. People in widely differing walks of life use chemistry everyday – the doctor and the chef, the farmer and the builder. Chemistry comes to the aid of the manufacturer of food, and also to the brewer and wine maker. The technician in the hospital laboratory uses chemistry to check for infections in blood samples. The forensic scientists uses chemistry to solve crimes. In agriculture, chemistry is used to increase the yields of crops and to control many pests. Chemicals keep the water supply safe and swimming pools clean. One of the largest industries in the world is the petrochemical industry – this industry is mainly associated with gasoline and the chemicals that come from crude oil. Drugs, synthetic dyes, plastics, and fabrics are produced by chemical means from nature’s raw materials.” Eyewitness Science “Chemistry” , Dr. Ann Newmark, DK Publishing, Inc., 1993, pg 6

2. Monday
Scientific method foldable
Variables foldable

3. Section 1.2 Chemistry and Matter
Chemistry- Study of matter and changes it undergoes
Matter- anything that has mass and takes up space

4. What’s the difference between mass and weight???

5. Mass- the amount of matter in an object
Weight- measure of matter and effect of gravity on an object

6. What do the prefixes macro- and micro- mean???

7. Macroscopic- do not need a microscope to see it
Submicroscopic- so tiny that parts can’t even be seen with microscope (ex: atom)

8. Submicroscopic events are explained by making models (a visual, verbal, or mathematical explanation of how things occur)

9. Section 1.3 Scientific Methods
Scientific Method- a systematic approach used in all scientific study
SCIENTIFIC METHOD Step 1> Observe: state the problem and gather all available information on it. observations: see things in the world, read books, ask an expert. Step 2> propose a hypothesis: a testable, reasonable explanation of an event, an educated guess based on all the best data collected up to that point. Usually stated in the form “If…then” Step 3> TEST THE HYPOTHESIS BY CONDUCTING CONTROLLED EXPERIMENTS EXPERIMENTS: Involve changing one variable at a time and noting the effect that change has. VARIABLE – any factor that could influence the outcome of an event. e.g. Referee, crowd, amount of oxygen available, temperature, wind In a controlled experiment , the variables are changed one at a time. After each variable is changed, scientists note the effect that particular variable is having on the results of the experiment. It is often difficult to isolate variables in an experiment. Scientists must make assumptions that may prove incorrect later. A synergistic effect may be observed where the variable interact in unexpected ways = 3! experiments require DATA – the results of the experiment; a collection of measurements. Step 4> draw a valid conclusion – follows from results of the experiments, not personal prejudices. Conclusions must be supported by data in order to be valid.

10. Steps of Scientific Method
1. Observation- the act of gathering information; may be qualitative data (from 5 senses) or quantitative data (numerical information)

11. 2. Formulate hypothesis (testable statement or prediction about what has been observed)

12. 3. Conduct Experiment (set of controlled observations that test hypothesis)

13. Variables Independent and Dependent Variables:
What they mean and how to use them

14. What is a variable?
In the design of a scientific experiment, a variable is any factor that changes from data group to data group.
Scientific experiments are designed so that the tested variables are the only things that are supposed to change from group to group; all other factors are to remain constant

15. A handy Mnemonic for Variables
Remember this phrase:
DRY MIX

16. Dependent Variable Dependent Variable
is the variable that Responds to the experimental design
and is graphed on the Y-axis

17. Independent Variable The variable Manipulated by the scientist
is called the Independent variable
and is graphed on the X-axis

18. Constant – variable that does not change during an experiment
Control- standard for comparison

19. For Example:
John wants to test how outside temperature effects pea plant growth. He sets up four identical greenhouse boxes where the only difference in the plant environments will be ambient temperature. One plant will grow at 10 °C. Another will grow at 20 °C which is room temperature. A third will grow at 30 °C. Finally, a forth will grow at 50 °C. After 30 days, the pea plants were measured for growth.

20. Pea Plant Growth (in cm)
Data Table
Temperature (in °C)
Pea Plant Growth (in cm) 10 13 20 45 30 37 50 4

21. Graph

22. 4. Analyze the data (more to come in chapter 2)

23. 5. Form a conclusion (judgment based on the information obtained; comparison of hypothesis with actual results)

24. Theory- explanation supported by many, many experiments
Ex: Big Bang Theory
Scientific Law- when the same conclusion is found many times with no exceptions
Ex: Newton’s Law of Motion

25. Scientific Method and Law
SCIENTIFIC METHOD Step 1> Observe: state the problem and gather all available information on it. observations: see things in the world, read books, ask an expert. Step 2> propose a hypothesis: a testable, reasonable explanation of an event, an educated guess based on all the best data collected up to that point. Usually stated in the form “If…then” Step 3> TEST THE HYPOTHESIS BY CONDUCTING CONTROLLED EXPERIMENTS EXPERIMENTS: Involve changing one variable at a time and noting the effect that change has. VARIABLE – any factor that could influence the outcome of an event. e.g. Referee, crowd, amount of oxygen available, temperature, wind In a controlled experiment , the variables are changed one at a time. After each variable is changed, scientists note the effect that particular variable is having on the results of the experiment. It is often difficult to isolate variables in an experiment. Scientists must make assumptions that may prove incorrect later. A synergistic effect may be observed where the variable interact in unexpected ways = 3! experiments require DATA – the results of the experiment; a collection of measurements. Step 4> draw a valid conclusion – follows from results of the experiments, not personal prejudices. Conclusions must be supported by data in order to be valid.

26. Discussion Which variable was the independent variable?
Which variable was the dependent variable?
Which plant represented the control group?

27. Tuesday Correct variables worksheet Scientific notation
Significant figures
Accuracy and precision

28. Chapter 2
Data Analysis

29. 2.1 Units of Measurement
In 1960 the metric system was updated and is called the Systeme Internationale d’Unites or the SI unit of measurement.
Standard units of measurement for ALL scientists to use worldwide.

30. Base Unit - unit of measurement based on an object or event in the physical world
The standard kilogram is stored in a vault at the International Bureau of Weights and Standards near Paris. It is made of a platinum-iridium alloy, and is shown here next to an inch-based ruler for scale.

31. Base Units:
1. Time: second (s)
2. Length: meter (m)
3. Mass: gram (g)

32. 4. Temperature: Kelvin (K)
5. Amount of substance: mole (mol) an international standard to measure an "amount of stuff" aka Mole! It refers to the number of atoms in 12 grams of carbon 12 (6.022 x 1023)
Avagadro’s Number

33. Derived Unit - A unit that is a combination of base units.
There are hundreds of units needed for measuring “everything,” but they are all derived from those base units.

34. Volume = L x W x H for a regularly shaped solid
cubic meter (m3),cubic centimeter (cm3) or cubic decimeter (dm3)
Unit for volume: liter (L) for a liquid
1 dm3 = 1 L cm3 = 1 mL

35. Density- ratio that compares the mass of an object to its volume
Units are grams per cubic centimeter (g/cm3)
1 ml = cm3

36. density = mass
volume
Density is a property that can be used to identify an unknown sample of matter.

37. Temperature Kelvin – SI base unit for temperature ºC + 273 = K
K – 273 = ºC
There are no negative temperatures in Kelvin

38. 2.2 Scientific Notation
Scientific Notation- expresses numbers as a multiple of two factors:
1. A number between 1 and 9
2. Ten is raised to a power (exponent).
2.0 x 103  3 is the exponent
2.0 x 103 = 2000
.20 or 20 would be WRONG because they are NOT numbers between 1 and 10!!

39. Scientific Notation Example
Count the number of places the decimal point moved and the direction
Convert to scientific notation.
Place decimal at end of number
Move decimal to place it behind the first number
You moved the decimal 5 places left. 
If decimal moves left, the exponent is positive
The # of times the decimal was moved becomes the exponent.
x 105

40. If decimal moves left, exponent is positive
if decimal moves right, exponent is negative

41. 8.72 x 10 – 4 Convert .000872 to scientific notation
Move the decimal behind first number that is NOT a zero
8.72 You moved the decimal 4 places right. 
The # of times the decimal was moved becomes the exponent.
If decimal moves right, exponent is negative.
The # of times the decimal was moved becomes the negative exponent
8.72 x 10 – 4

42. To convert Scientific Notation to Standard Notation Reverse the above steps:
If the exponent is positive move the decimal to the right the same number of places as the exponent.
2.5 x =
If the exponent is negative move the decimal to the left the same number of places as the exponent.
2.5 x =

43. Adding, subtracting, multiplying, and dividing in Scientific Notation by using the calculator
Use “EE” or “exp” key on your calculator to replace “ x 10^”
Ex: 8.72 x 10-4 would be 8.72”EE”-4

44. Sect. 2.3: How reliable are measurements?
Accuracy – how close a measured value is to an accepted or true value
Precision – how close a series of measurements are to each other
Compare to throwing darts bottom of pg 36.

46. ACCURACY VS. PRECISION:
THIS CLOCK is more precise than THIS CLOCK
HOWEVER, if the actual time is 3:00, then the second clock is more accurate than the first one.
ACCURACY = HOW CLOSE A MEASUREMENT IS TO THE TRUE VALUE
PRECISION = EXACTNESS

47. Percent error – the ratio of an error to an accepted value.
% error = experimental – accepted x 100
accepted value
Example:
Density of lead is 11.3, you had 10.3 in your experiment.
Difference is 1
So x 100 = 8.8%
11.3

48. Significant Figures Accuracy is limited by the available tools.
Sig figs are based on instrument precision (numbers can only be as exact as the instrument is)
Instruments must be calibrated to assure accuracy.

49. The “best” number is the one with the most decimal places.
So 3.54 g is MORE precise
than 3.5 g.
Significant figures - include all known digits plus ONE estimated digit.

50. Having Trouble with Sig Figs? Try this:
1. Determine if the decimal point is “present” or “absent”.
2. Picture a map of the U.S. with the Pacific Ocean on the left and the Atlantic Ocean on the right.
PACIFIC ATLANTIC
Decimal present Decimal absent
 
3. If the decimal point is “present”, imagine an arrow LEFT from the Pacific Ocean pointing to the number. (Think “P” for “present” and “Pacific”). 
4. If the decimal point is “absent”, imagine an arrow RIGHT from the Atlantic Ocean pointing to the number (“A” for “absent” and “Atlantic”). 
5. Start counting digits when the arrow hits a non-zero digit. Each digit after that is significant.

51. EXAMPLES:
 has 4 sig figs (9 is the first non-zero digit counting from Pacific)
 has 4 sig figs (1 is the first non-zero digit counting from Pacific)
34005  has 5 sig figs (5 is the first non-zero digit counting from Atlantic)
1200  has 2 sig figs (2 is the first non-zero digit counting from Atlantic)

52. Rounding Numbers
If last number is five or greater, round up
If last number is less than five, leave alone.

53. Rounding Examples 12.27845 Round to 3 significant figures 12.3
12.28
Round to 2 significant figures 12

54. Math with Sig Figs
When adding/subtracting, answer will be rounded to least number of decimal places cm cm cm
cm so the answer must have only one digit to the right of the decimal
77.2 cm is the answer

55. When multiplying/dividing, answer will be rounded to least number of sig figs
3.20 cm x 3.65 cm x 2.05 cm = cm3
all the factors have 3 sig figs
So the answer should have 3 sig figs
cm3 Becomes 23.9 cm3

56. Mult/Div Round to the least number of sig figs
2.50 m x m x m = m3
3 sig figs 1 sig fig 3 sig figs
The answer should have one sig fig.
The answer would be 0.6 m3
(1200 cm ./ cm) ./ cm = 1 cm3
2 sig figs sig fig sig figs
The answer should have 2 sig figs
The answer would be 1.0 cm3

57. WEDNESDAY
Practice significant figures and scientific notation worksheet

58. Thursday
Grade worksheet
Do graph foldable

59. Section 2.4: Representing Data
A goal of many experiments is to discover whether a pattern exits.
Data in a table may not show an obvious pattern.
Graphing can help reveal a pattern.

60. Graphs
Graph – visual display of data
4 types of Graphs
Circle graph/pie chart
Bar Graph
Line Graph
Scatter Plot

62. HOW TO CHOOSE WHICH TYPE OF GRAPH TO USE?
When to Use a Pie Chart.
a “part of a whole” or as percentages

63. When to Use a Bar Graph.
used to show how a quantity changes with certain factors
to compare things between different groups
to track changes over time
Bar graphs are best when the changes are larger.

64. Scatterplot
A scatter plot is a graph of a collection of ordered pairs (x,y).
The graph looks like a bunch of dots, but some of the graphs are a general shape or move in a general direction

65. When to Use a Line graph.
used to track changes over short and long periods of time
When smaller changes exist, line graphs are better to use than bar graphs
used to compare changes over the same period of time for more than one group

66. Distance /Time Graph

67. When Are Histograms Used?
• Summarize large data sets graphically
• Compare measurements to specifications
• Communicate information to the team
• Assist in decision making

68. Friday
Measurement Lab