1. Chapter 1: Chemistry and You
Explain why a knowledge of chemistry is central to many human endeavors.
List and describe the steps of the scientific method.
Explain the basic safety rules that must be followed when working in the chem lab.
Identify the metric units of measurement used in chemistry.
Explain what causes uncertainty in measurements.
Compare accuracy and precision.
Explain how to use significant figures and scientific notation.
Calculate percent error.
Define density and explain how it is calculated.
Explain how dimensional analysis and conversion factors are used to solve problems in chemistry.

2. Vocab Chemistry Scientific method Observation Hypothesis Experiment
Conclusion
Natural law
Theory
Variable
Experimental control
Metric system
International System of Units (SI)
Base unit
Mass
Volume
Metric prefix
Precision
Accepted unit
Accuracy
Significant digit
Percent error
Density
Dimensional analysis
Conversion factor

3. Chapter 1: Chemistry and You
Look at the pic on p. 2 and read the caption
Name some of the basic chemical substances that make up your body.
Name some other chemical processes, besides digestion, that occur in your body.
Can you think of an important chemical reaction that occurs in plants and trees?

4. Section 1-1
What is Chemistry?

5. Chemistry in Action
Chemistry is a broad science that touches nearly every aspect of human life.
What are some ways chemistry affects the 2 careers mentioned in the section?
Examining a wetlands habitat
Preserving historical artifacts

6. The Central Science
Chemistry has been called the central science b/c it overlaps so many sciences
Careers that use chemistry
Hair stylists
Construction
Biologists
What others?
Possible chemistry careers
Police departments (CSI)
Perfume companies
Research chemists

7. Why Study Chemistry? It is involved in many aspects of life
Helps you to understand the world around you

8. Cleaning Priceless Art
Read the “Connection” box on p. 6
What occupation is using chemistry?
What did they do to clean the art?
Why are some people upset about their actions?

9. Section 1-2
The Scientific Method

10. Theory modified as needed
The Scientific Method
Observation
Question
Hypothesis
Experiment
Conclusion
A way of answering questions about the world we live in
Oscar Has Extremely Colorful T- Shirts
Theory
(Model)
Natural Law
Theory modified as needed
Prediction
Experiment

11. Observation
Seeing a problem or asking a question that you cannot answer
Always leads to a question

12. Hypothesis An educated guess
Usually asked in a “cause-effect” statement
Must be able to test the hypothesis

13. Experiment A test of the hypothesis
Data will be collected and analyzed
Must have 1 variable and at least 1 constant
Variable – the particular factor being tested

14. Conclusion The result of the analyzed data
May agree or disagree with your hypothesis

15. Theory
Answers the original question as well as any others formed during the process
Predicts the results of further experiments

16. Scientific/Natural Law
Describes how nature behaves but not why

17. 1-2 Section Review
On looseleaf to turn in, page 13 (1-5)

18. Bikini Bottom Experiments
With your small group, complete the SpongeBob worksheet
SpongeBob Scientific Method.pdf

19. Section 1-3
Safety in the Lab

20. Section 1-4
Units of Measurement

21. Units of Measurement Measurement: always includes a number and unit
If someone is 7 feet tall, “7” is the number and “feet” is the unit
Saying someone is 7 does not tell you enough info
They could be 7 yrs old, 7 feet tall, 7 inches tall, …
Feet and inches are part of the English system of measurement
In science, we use the Metric system
All scientists, no matter their country or language, use the metric system

22. United States, Liberia, and Burma

23. International System of Units
SI units used by all scientists around the world
Based on 7 metric units called base units
Length meter (m)
Mass kilogram (kg)
Time second (s)
Count/Quantity mole (mol)
Temperature Kelvin (K)
Electric Current ampere (A)
Luminous Intensity candela (cd)

24. Derived Units
Area square meter (m2) Volume cubic meter (m3) Force Newton (N) Pressure Pascal (Pa) Energy joule ( J ) Power watt (W) Voltage volt (V) Frequency hertz (Hz) Electric charge coulomb (C)

25. Units Science is a process, not a collection of rules
The most frequently used units in class that differ than SI:
Temperature - Celsius (˚C)
Volume – liter (L)
Pressure – atmosphere (atm) millimeters of mercury (mmHg)
Energy – calorie (cal)

26. Commonly used units Length Mass Volume A dime is 1 mm thick
A quarter is 2.5 cm in diameter
Average height of a man is 1.8 m
Mass
A nickel has a mass of 5 g
A 120 lb woman has a mass of about 55 kg
Volume
A 20 oz can of soda has a volume of 360 mL
A ½ gallon of milk is equal to 2 L

27. Metric Prefixes King Henry Died by drinking chocolate milk
Abbreviation
Meaning
kilo- k
1 000
hecta- H
100
deca- D 10
Base Unit 1
deci- d
0.1
centi- c
0.01
milli- m
0.001
King Henry Died by drinking chocolate milk
Base units include meter, liter, second, gram

28. How to Use Prefixes
kilo-
hecto-
deca-
Base units
deci-
centi-
milli-

29. Example How many millimeters are in a meter? 1 meter = mm
kilo-
hecto-
deca-
base units
deci-
centi-
milli-

30. Practice Problems Convert a volume of 16 deciliters into liters
Convert 1.45 meters into centimeters
145 cm
Convert a volume of 8 deciliters into liters
0.8 L
Is 5 centimeters longer or shorter than 8 millimeters? Explain.
5 cm is longer than 8 mm b/c 0.05 m is greater than 0.008m

31. Metric Mania
Worksheet

32. Section 1-5
Uncertainty in Measurement

33. Making Measurements
When making a measurement, write down everything given to you with one uncertain estimated number
5.1 inches is easy to spot but we still need 1 uncertain number
My estimation = 5.12 inches
Measurements are uncertain b/c:
Measuring instruments are never completely free of flaws
Measuring always involves some estimation

34. Reliability in Measurement
Precision: the same result is given over and over under the same conditions
Accuracy: the result is close to a reliable standard
Accepted value: the reliable standard
High Precision
High Accuracy

35. Section 1-6
Working with Numbers

36. Working with numbers Measurements are rarely used just by themselves.
Usually used in some form of mathematics (+, -, x, or ÷)
Produces values of mass, temperature, volume, etc.

37. Significant Figures (Digits)
The certain digits and the estimated digit of a measurement
Example: In the # 31.7, there are 3 sig figs
The 3 and 1 are certain digits while the 7 is the uncertain digit

38. Rules for Sig Figs Nonzero #: any number that is not a zero Zeros
Never count “leading zeros”
0023  only count the 2 and 3
0.054  only count the 5 and 4
Always count “captive” or “sandwiched” zeros
303  count the 3, 0, and 3
“Trailing zeros”: zeros to the right
Only count if used with a decimal point
5400  only count the 5 and 4
5.400  count the 5, 4, 0, and 0

39. Example How many sig figs are in 0.057 010 g? Nonzero numbers:
Captive zeros
Trailing zeros when there is a decimal
Final Answer
5 significant figures

40. Practice Problems How many sig figs in the following numbers?kg
6 sig figs
3500 V
2 sig figs 3500 L
4 sig figs m
3 sig figs
520 mL
2 sig figs 520 ms
3 sig figs

41. Sig Fig Practice Wkst

42. Significant Figures in Calculations
Multiplying and Dividing
The answer will have the same # of sig figs as the measurement with the smallest # of sig figs
Volume = m x m x m
(4 sig figs) (3 sig figs) (2 sig figs)
= m3
= 4.8 m3

43. Sig Figs in Calculations
Adding and Subtracting
The answer will have the same # of decimal places as the measurement with the smallest # of decimal places g g g g g
Since there aren’t any decimals in 1407, our answer will not have decimals
Final answer = 2540 g

44. Practice Problems 6.15 m x 4.026 m = 1.45 m x 1.355 m x 2.03 m =
g g =
g = g
0.258 mL ÷ mL =
mL = mL

45. More Practice
Worksheet

46. Scientific Notation In science we work w/ very large and very small #s
For example:
1 drop of water contains = 1,700,000,000,000,000,000,000 molecules
The mass of 1 proton = kg

47. Scientific Notaion
To make it easier for ourselves, we use scientific notation
1 drop of water contains = 1,700,000,000,000,000,000,000 molecules
1 drop of water contains = 1.7 x 1021
The mass of 1 proton = kg
The mass of 1 proton = x 10-21

48. How to make # into scientific notation
Write in scientific notation
Write down the full number
1700
Move the decimal until it is right after the first 1-10 number
1700   1.700
Write down this new number without the zeros
1.7
Place “x 10” after this number
1.7 x 10
Count how many times you had to move the decimal and place that number after the 10 as an exponent
If you move to the right = negative exponent
If you move to the left = positive exponent
1.7 x 103

49. Examples
37 700
3.77 x 104
1.024 x 106
3.901 x 10-9
8960
8.96 x 103
2.3 x 10-4

50. Percents Data will often be given as a percent
If it is a fraction, just divide and multiply by 100
Ex: 900 million kilograms of plastic soft drink bottles are produced each year million kilograms of them are recycled.
180 million kilograms
900 million kilograms
= 0.2 x 100% = 20%

51. Percent Error
A measurement can be compared to its accepted value by finding the percent error
% error can be positive or negative
Positive = measured value is greater than accepted
Negative = measured value is less than accepted
measured value – accepted value
accepted value
% error =
x 100%

52. Example
In an experiment dealing with finding the boiling point of water, you performed 3 experiments and found water to boil at 98.4˚C, 98.9 ˚C, and 97.5˚C. What is the average and % error of your data? (Hint: the accepted value of the boiling point of water is 100˚C)
= / 3 = 98.3
% error = (100 – 98.3) / 100 x 100 = 1.7%

53. Practice
Work the problems on your “Accuracy Precision and Percent Error” worksheet from a few class periods ago

54. Density Density – compares the mass of an object to its volume
measured in:
grams per cubic centimeters (g/cm3)
grams per milliliter (g/mL)
Mass
Density =
Volume

55. Density Problems
If a sample of aluminum has a mass of 13.5g and a volume of 5.0 cm3, what is its density?
2.7 g/cm3

56. Suppose a sample of aluminum is placed in a 25 mL graduated cylinder containing 10.5 mL of water. The level of the water rises to 13.5 mL. What is the mass of the aluminum sample? (Use the density you found in the problem before this)
8.1 g

57. A piece of metal with a mass of 147g is placed in a 50mL graduated cylinder. The water level rises from 20mL to 41mL. What is the density of the metal?
7 g/mL

58. What is the volume of a sample that has a mass of 20g and a density of 4g/mL?

59. A metal cube has a mass of 20g and a volume of 5cm3
A metal cube has a mass of 20g and a volume of 5cm3. Is the cube made of pure aluminum? Explain. (Hint: Pure Aluminum will have a density of 2.7g/cm3.)
4 g/cm3

60. Dimensional Analysis Technique of converting between units
How many feet are in 86 centimeters?
We know 12 inches = 1 foot
We also know 1 inch = 2.54 centimeters
86 cm 1 in ft
2.54 cm in
= 2.82 ft

61. Practice Problems
Use Fig 1-29 on page 38 to help you solve the following problems
How many cubic centimeters are in 2.3 gal?
8 700 cm3
How many meters are in 3.5 mi?
5 600 m
How many pascals are in 770 mm Hg? Pa
How many seconds are in 10.5 hours? s
How many days are in seconds?
days

62. Graphing How to draw a scientific graph
Need independent variable (x – axis)
the variable being changed
Need dependent variable (y – axis)
the variable being changed by the independent variable
Label each axis
Do not connect each dot, use a “line of best fit”
Give the graph a title which tells what it is of

63. Example
A balloon is filled with air and attached to the bottom of a large container of water. If the water temperature is changed, by heating or adding ice, the volume of the air in the balloon also changes. Data was collected from taking volume measurements at different temperatures.
Independent variable: temperature
Dependent variable: volume

64. Sample Graph Trial Temperature (˚C) Volume (mL) 1 25 101.3 2 30 103.235
103.4 4 40
105.0 5 45
106.7 6 50
108.4 7 55
110.0 8 60
111.5 9 65
112.9 10 70
114.2