1. Welcome to the World of Chemistry

2. Chemistry The study of:
the composition (make-up) of matter and its changes

3. What is matter?
Anything that:
has mass
and
occupies space (volume).

4. Why study Chemistry Explain the natural world Prepare for a career
Directly- in a lab
Indirectly- problem solving and thinking skills
Be an informed citizen
Vote
Don’t get scammed

5. Branches of Chemistry Many major areas of study for specialization
Several career opportunities
Also used in many other jobs

6. 1. Organic Chemistry
Organic is the study of matter that contains carbon
Organic chemists study the structure, function, synthesis, and identity of carbon compounds
Useful in petroleum industry, pharmaceuticals, polymers

7. 2. Inorganic Chemistry
Inorganic is the study of matter that does NOT contain carbon
Inorganic chemists study the structure, function, synthesis, and identity of non-carbon compounds
Polymers, Metallurgy

8. 3. Biochemistry
Biochemistry is the study of chemistry in living things
Cross between biology and chemistry
Pharmaceuticals and genetics

9. HONK if you passed p-chem
4. Physical Chemistry
HONK if you passed p-chem
Physical chemistry is the physics of chemistry… the forces of matter
Much of p-chem is computational
Develop theoretical ideas for new compounds

10. 5. Analytical Chemistry
Analytical chemistry is the study of high precision measurement
Find composition and identity of chemicals
Forensics, quality control, medical tests

11. Variables Controlled experiment- Only change one thing at a time
Independent variable- What you change or control directly
Dependent variable – What changes as a result. No direct control

12. Learning Check
Stella thinks that if people are exposed to ultraviolet light then they are more likely to get skin cancer. Stella designs an experiment wherein sample A consisted of people were exposed to ultraviolet light and sample B was not.
Justin believes that the temperature change during the fall months causes the color of the leaves to change. He placed some plants in 80 degree rooms and some in 60 degree rooms. He then observed the color of the leaves for a total of 1 month. At the end of the month Justin observed that ¾ of the plants in the 60 degree temperature had changed colors and only ¼ of the plants in the 80 degree temperature had changed colors

13. Scientific Method- one of multiple versions of the steps
State the problem clearly.
Gather information.
Form a hypothesis
Test the hypothesis.
Evaluate the data to form a conclusion.
Share the results.

14. What is Scientific Notation?
Scientific notation is a way of expressing really big numbers or really small numbers.
For very large and very small numbers, scientific notation is more concise.

15. Scientific notation consists of two parts:
A number between 1 and 10
A power of 10
N x 10x

16. To change standard form to scientific notation…
Place the decimal point so that there is one number in front
Count the number of places the decimal point has “moved”
This will be the exponent on the 10.
If the original number was less than 1, then the exponent is negative. If the original number was greater than 1, then the exponent is positive.

17. Examples Given: 289,800,000 Use: 2.898 (moved 8 places)
Answer: x 108
Given:
Use: 5.67 (moved 4 places)
Answer: 5.67 x 10-4

18. To change scientific notation to standard form…
Simply move the decimal point to the right for positive exponents
Move the decimal point to the left for negative exponents
(Use zeros to fill in places.)

19. Example
Given: x 106
Answer: 5,093,000 (moved 6 places to the right)
Given: x 10-4
Answer: (moved 4 places to the left)

20. Learning Check Express these numbers in Scientific Notation: 405789 2

21. Information from U.S. Metric Association
SI measurement
Le Système international d'unités
The only countries that have not officially adopted SI are Liberia (in western Africa) and Myanmar (a.k.a. Burma, in SE Asia), but now these are reportedly using metric regularly
Metrication is a process that does not happen all at once, but is rather a process that happens over time.
Among countries with non-metric usage, the U.S. is the only country significantly holding out. The U.S. officially adopted SI in 1866.
Information from U.S. Metric Association

22. Chemistry In Action
On 9/23/99, $125,000,000 Mars Climate Orbiter entered Mars’ atmosphere 100 km lower than planned and was destroyed by heat.
1 lb = 1 N
1 lb = 4.45 N
“This is going to be the cautionary tale that will be embedded into introduction to the metric system in elementary school, high school, and college science courses till the end of time.”

23. In every measurement there is a Number followed by a
Stating a Measurement
In every measurement there is a
Number followed by a
Unit from a measuring device
The number should also be as precise as the measurement!

24. UNITS OF MEASUREMENT Use SI units — based on the metric system Length
Mass
Volume
Time
Temperature
Meter, m
Kilogram, kg
Liter, L
Seconds, s
Celsius degrees, ˚C
kelvins, K

25. Learning Check Match L) length M) mass V) volume
____ A. A bag of tomatoes is 4.6 kg.
____ B. A person is 2.0 m tall.
____ C. A medication contains 0.50 g Aspirin.
____ D. A bottle contains 1.5 L of water.

26. Metric Prefixes Kilo- means 1000 of that unit
1 kilometer (km) = meters (m)
Centi- means 1/100 of that unit
1 meter (m) = 100 centimeters (cm)
Milli- means 1/1000 of that unit
1 meter (m) = millimeters (mm)
1 centimeter (cm) = 10 millimeters(mm)

27. Metric Prefixes

28. Learning Check 1. 1000 m = 1 ___ 2. 100 ___= 1 m 3. 10 ___ = 1 L
10 cm = 1 ___
10000 ___ = 1 g

29. Learning Check Select the unit you would use to measure 1. Your height
a) millimeters b) meters c) kilometers
2. Your mass
a) milligrams b) grams c) kilograms
3. The distance between two cities
a) millimeters b) meters c) kilometers
4. The width of an artery

30. Conversion Factors
Fractions in which the numerator and denominator are EQUAL quantities expressed in different units
Example: in. = 2.54 cm
Factors: 1 in and cm
2.54 cm in.

31. Learning Check 1. Liters and mL 2. Hours and minutes
Write conversion factors that relate each of the following pairs of units:
1. Liters and mL
2. Hours and minutes
3. Meters and kilometers

32. Equalities length 10.0 in. 25.4 cm
State the same measurement in two different units
length
10.0 in.
25.4 cm

33. Using Conversion Factors
How many minutes are in 2.5 hours?

34. Temperature Scales Fahrenheit Celsius Kelvin Anders Celsius 1701-1744
Lord Kelvin
(William Thomson)

35. VIII. Temperature vs. Heat
The average kinetic energy (how fast matter is moving) of matter
Heat:
The total amount of movement in a sample
Absolute Zero:
The temperature at which all molecular movement stops (cannot happen) 0K

36. Temperature Scales Fahrenheit Celsius Kelvin 32 ˚F 212 ˚F 180˚F 100 ˚C
Boiling point of water
32 ˚F
212 ˚F
180˚F
100 ˚C
0 ˚C
100˚C
373 K
273 K
100 K
Freezing point of water
Notice that 1 kelvin = 1 degree Celsius

37. Calculations Using Temperature
K = (˚C)
°F = 9/5 °C
°C = (°F - 32) * 5/9

38. Temperature Conversions
A person with hypothermia has a body temperature of 29.1°C. What is the body temperature in °F?
°F = 9/5 (29.1°C) =
= 84.4°F

39. Learning Check
The normal temperature of a hummingbird is 32.3°C. What is that temperature in °K?

40. Learning Check Pizza is baked at 455°F. What is that in °C? 1) 437 °C

41. Can you hit the bull's-eye?
Three targets with three arrows each to shoot.
How do they compare?
Both accurate and precise
Precise but not accurate
Neither accurate nor precise
Define accuracy and precision

42. Numbers There are 2 different types of numbers Exact Measured
Exact numbers are infinitely important/correct
Measured number = measured with a measuring device so these numbers have ERROR.
Eg with a ruler, thermometer, balance
When you use your calculator your answer can only be as accurate as your worst measurement

43. Exact Numbers
1.An exact number is obtained when you count objects or use a defined relationship.
2. Counting objects are always exact 2 soccer balls 4 pizzas
3. Exact relationships, predefined values, not measured 1 foot = 12 inches 1 meter = 100 cm
For instance is 1 foot = inches? No
1 ft is EXACTLY 12 inches.

44. Learning Check A. Exact numbers are obtained by
1. using a measuring tool
2. counting
3. definition
B. Measured numbers are obtained by

45. Learning Check Classify each of the following as an exact or a
measured number.
1 yard = 3 feet
The diameter of a red blood cell is 6 x 10-4 cm.
There are 6 hats on the shelf.
Gold melts at 1064°C.

46. Significant Figures
The numbers reported in a measurement are limited by the measuring tool
Significant figures in a measurement include the known digits plus one estimated digit

47. Reading a Meterstick
. l I I I I cm
First digit (known) = ?? cm
Second digit (known) = ? cm
Third digit (estimated) between
Length reported = cm
or cm
or cm

48. Learning Check . l8. . . . I . . . . I9. . . .I . . . . I10. . cm
What is the length of the line?
1) cm
2) cm
3) cm
How does your answer compare with your neighbor’s answer? Why or why not?

49. Zero as a Measured Number
. l I I I I cm
What is the length of the line?
First digit ?? cm
Second digit ? cm
Last (estimated) digit is cm

50. Always estimate ONE place past the smallest mark!

51. Counting Significant Figures
RULE 1. All non-zero digits in a measured number are significant.
Number of Significant Figures
38.15 cm 4
5.6 ft 2
65.6 lb ___
m ___

52. Leading Zeros
RULE 2. Leading zeros (any zero before the first non zero) in decimal numbers are NOT significant.
Number of Significant Figures
0.008 mm 1
oz 3
lb ____
mL ____

53. Sandwiched Zeros
RULE 3. Zeros between nonzero numbers are significant.
or sandwiched zeros are significant
Number of Significant Figures
50.8 mm 3
2001 min 4
0.702 lb ____
m ____

54. Trailing Zeros 25,000 in. 2 200. yr 3 48,600 gal ____
RULE 4. Trailing zeros (zeros at the end) are significant only if there is a decimal
Number of Significant Figures
25,000 in. 2
200. yr 3
48,600 gal ____
25,005,000 g ____

55. Learning Check A. Which answers contain 3 significant figures?
1) ) ) 4760
B. All the zeros are significant in
1) ) ) x 103
C. 534,675 rounded to 3 significant figures is
1) ) 535, ) 5.35 x 105

56. Learning Check
In which set(s) do both numbers contain the same number of significant figures?
1) and 22.00
2) and 40
3) and 150,000

57. Learning Check
State the number of significant figures in each of the following:
A m
B L
C g
D m
E. 2,080,000 bees

58. Practice Rule #2 Rounding
Make the following into a 3 Sig Fig number
Your Final number must be of the same value as the number you started with,
129,000 and not 129
1.5587
1367
128,522
106
1.56
.00374
1370
129,000 or 1.29x106
1.67 106

59. Examples of Rounding 0 is dropped, it is <5
For example you want a 4 Sig Fig number
0 is dropped, it is <5
8 is dropped, it is >5; Note you must include the 0’s
5 is dropped it is = 5; note you need a 4 Sig Fig
780,582
1999.5
4965
780,600
2000.

60. Significant Numbers in Calculations
A calculated answer cannot be more precise than the measuring tool.
A calculated answer must match the least precise measurement.
Significant figures are needed for final answers from
1) adding or subtracting
2) multiplying or dividing

61. Adding and Subtracting
The answer has the same number of decimal places as the measurement with the fewest decimal places.
one decimal place
two decimal places
26.54
answer one decimal place

62. Learning Check
In each calculation, round the answer to the correct number of significant figures.
A =
1) ) ) 257
B =
1) ) ) 40.7

63. Multiplying and Dividing
The answer cannot have more significant figures than either of the original numbers.
Round (or add zeros) to the calculated answer until you have the same number of significant figures as the measurement with the fewest significant figures.

64. Learning Check
A X 4.2 =
1) ) )
B ÷ =
1) ) ) 60
C X =
X 0.060
1) ) )

65. IV. Physical vs. Chemical Properties
Properties of an element or compound that can be observed or measured WITHOUT a chemical reaction
Ability of an element or substance to undergo a chemical reaction (bond breaking) and form a NEW substance

66. IV. Physical vs. Chemical Properties
Color, texture, odor, density, melting/freezing temps, solubility, volume, mass
VIDEO EXAMPLE
Reactivity, pH (acidity), ability to rust, decompose, ferment, combust
VIDEO EXAMPLE

67. IV. Physical vs. Chemical Properties

68. V. Physical vs. Chemical Changes
It does NOT produce a new substance, it just changes the position of the particles
Changing a substance into a NEW substance (bonds are broken and then new ones formed)
A color change may occur and a NEW s, l, or g is formed
A change that does NOT affect a substance’s chemical position

69. V. Physical vs. Chemical Changes
Any phase change (freezing, melting…), dissolving, mixing, cutting
Burning, rusting, fermentation, cooking/baking

70. V. Physical vs. Chemical Changes
liquid water freezes to ice
salt dissolves in water
liquid nitrogen in plastic bottle bursts open
rusting on a pan
potassium reacting with water to form potassium hydroxide and hydrogen gas
2K (s) + 2H2O (l) -> 2KOH (aq) + H2 (g)

71. IV. Physical vs. Chemical Properties

72. Mass cannot be created or destroyed in a chemical reaction
Conservation of Mass:
Mass cannot be created or destroyed in a chemical reaction
The total mass of reactants equals the total mass of the products
Example (video clip)
Silver nitrate (AgNO3) and sodium chloride (NaCl) solutions before and after mixing

73. Examples: 50 g + Sodium+ 76 g 126 g Sodium Chloride Chlorine 
1) If 50.0 grams of sodium reacts with chlorine to form 126 grams of sodium chloride. How many grams of chlorine reacted?
2) If g of water is separated into hydrogen and oxygen gas, and the hydrogen gas has a mass of 20.0 g. What is the mass of the oxygen gas produced?
50 g +
Sodium+
76 g
126 g
Sodium Chloride
Chlorine 
178.8 g 
H2O 
20 g +
158.8 g
H2 + O2