1. Scientific Notation

2. Scientific Notation
Very large or small numbers can be written in scientific notation.
Scientific notation uses decimals and a power of 10 to represent the original number.
To write a number is scientific notation, the number must be written with a decimal point after the first digit.

3. Converting to Scientific Notation
Write out the entire number.
Count the number of places you move the decimal point so that the number is after the first digit.
If you moved the decimal to the LEFT, write 10 raised to the positive of the number of places you moved the decimal.
If you moved the decimal to the RIGHT, write 10 raised to the negative of the number of places you moved the decimal.

4. Write In Scientific Notation
0.2365

5. Measuring Accurately

6. Accuracy vs. Precision Accuracy Precision
The extent to which a measured value agrees with the accepted value
Percent error between experimental or calculated numbers and accepted number
Degree of exactness to which a quantity is measured.
Measurements may be precise, but may not be accurate.
Based on the scale of the measuring devise.

7. Recording and Reporting Measurements
When recording a measurement, always record all values given by the devise and the “guess” at the last place value.
For example, if you measure a strip of paper to be 5.6 cm, you would want to add one more digit to the end of your number based on where you think the paper ends. If it ends right on the 0.6 mark, then your value would be 5.60 cm. If it appears to go halfway between 0.6 and 0.7 your value would be 5.65 cm.

8. Liquid Measurements- Meniscus
Water is a “sticky” molecule.
Water will climb the sides of the glass.
This is called the Meniscus.

9. The Metric System

10. Space Station Issues
The International Space Station (ISS) is regularly populated with Russians, Americans, Japanese, and Europeans.
Language is a problem.
So math is not a problem, one system of units has been adopted.
Measure out 5 feet.
How many meters is that?

11. The Metric System Mass (how heavy things are) is measured in grams.
Volume (how much space something takes up) is measured in liters.
Length (how far, long, wide something is) is measured in meters.

12. 1 gram of pure gold is worth ~$100
Examples of Mass
1 gram of pure gold is worth ~$100
A Penny weighs 2.5 grams

13. 2 Liters 3.8 Liters Examples of Volume A Bottle of Soda Gallon of Milk

14. Examples of Length A stride is approximately 1 meter
A car is approximately 4 meter

15. Importance of Prefixes
Which is easier to report? grams or 3 nanograms

16. Prefixes King Henry Died from drinking chocolate milk Kilo = 1000
Hecto = 100
Deca = 10
Free = grams, liters, meters
Deci = .1
Centi = .01
Milli = .001

17. OR…. King Have Diamonds but diamonds cost money Kilo = 1000
Hecto = 100
Deca = 10
Base unit= grams, liters, meters
Deci = .1
Centi = .01
Milli = .001

18. Convert 5000 grams to kilograms
K H D f d c m

19. Convert 5000 millimeters to meters Convert 15 deciliters to hectoliters

20. 9000 mL to DL .006 Km to m 54 cg to g .408 L to dL 905 Hm to cm
Practice Conversions
9000 mL to DL
.006 Km to m
54 cg to g
.408 L to dL
905 Hm to cm
9 g to Kg

21. Importance of the Metric System
Chemists work across the globe to further our understanding.
We need to be able to share our information so that we can make discoveries more quickly.

22. Conversions

23. Conversions Simplify Life
Conversions allow you to represent the same amount in different units.

24. Consider Eggs
Eggs are not sold individually. You buy eggs or 1 dozen. 1dozen = 12 eggs.
Units

25. Setting Up A Converson…
Make sure you have the same units on the top and the same units on the bottom
1 dozen = x dozen __________ __________ 12 eggs 36 eggs 3
1 dozen = x dozen
_________ ____________
12 eggs eggs 2
1 dozen = x dozen
_________ __________
12 eggs eggs ?

26. ___________ _____________ 12 eggs 15 eggs
1 dozen = x dozen
___________ _____________
12 eggs eggs
Step One: Cross Multiply
Step Two: Divide
Step Three: Check Units

27. _____________ ________________
1 dozen = x dozen
_____________ ________________
12 eggs eggs
Try one yourself. =
= x

28. 1 atm 4 atm 760 Torr X Torr Pressure Conversions 1 atm = 760 Torr

29. In chemistry we don’t use dozens. We use Moles
In chemistry we don’t use dozens. We use Moles. A mole is a number of particles.

30. Number of Particles
1 Mole = 6.02 x 1023 Particles 60,200,000,000,000,0 00,000,000,000 Particles

31. Mole Conversions 1 mole of Carbon = 12 grams
One mole of an element has a specific mass.
We can convert between moles and grams.
1 mole of Carbon = 12 grams

32. How many moles is 30 grams of Carbon?
1 mole of Carbon = 12 grams
How many moles is 30 grams of Carbon?

33. How many moles is 59 grams of Oxygen?
1 mole of Oxygen = 32 grams
How many moles is 59 grams of Oxygen?

34. Math Review

35. You have 20 beads; 6 of them are red
You have 20 beads; 6 of them are red. What is the percentage of red beads?

36. How much is 13% of 54?

37. How much is 54% of 120?

38. How much is 98% of 6?

39. 35𝑥=70

40. 5𝑥 +6=26

41. 50= 𝑥+70

42. 5𝑥−10=10

43. 25= 75 𝑥

44. 14𝑥= 3 2

45. 𝑥 2 =64

46. 𝑥 2 + 3=39

47. 5 𝑥−2 = 10

48. 25 𝑥 + 50=55

49. 𝑥 =5

50. 1 mole = 40 grams. How many moles is 60 grams?

51. 1 mole = 22.4 liters. How many liters is 3 moles?

52. 12 Eggs = 1 dozen eggs. How many eggs is 4.66 dozen?

53. 100 cents = 1 dollar. How many dollars is 14,000 cents?

54. 1 mole = 32 grams. How many grams does 2.5 moles weigh?

55. 1 atm = 760 Torr. How many Torr is 3.4 atms?

56. Significant Figures

57. Significant Figures
When using a measuring device, the last digit is always an estimate.
To make sure all calculations with measurements are accurate, we have to make sure our answers do not have more digits than the original measurements.
Scientists use significant figures to help solve this issue.
The more sig figs a measurement has the more precise it is.

58. What Numbers are Significant?
All digits other than zero are significant numbers.
Zeros are significant if:
It is surrounded by two non-zero digits
If more than one zero is surrounded by non-zero numbers, all the surrounded zeros are significant
If a decimal is present, all the zeros after the first non-zero number are significant
All numbers written in scientific notation are significant

59. Steps to Counting Sig Figs
Step 1: Is the decimal point present or absent? Present: start from left Absent: start from right Step 2: Start counting with the first number that isn’t zero Step 3: Once you start counting, count everything, including zeros

60. How many significant figures?
The Rules of Zero
How many significant figures?
Pacific
Present
Left
Atlantic
Absent
Right
0.554
3 Sig Figs

61. How many significant figures?
The Rules of Zero
How many significant figures?
Pacific
Left
Pacific
Present
Left
Atlantic
Absent
Right
Atlantic
Right
8004
4 Sig Figs

62. How many significant figures?
The Rules of Zero
How many significant figures?
Pacific
Present
Left
Atlantic
Absent
Right
1.0450
5 Sig Figs

63. How many significant figures?
The Rules of Zero
How many significant figures?
Pacific
Present
Left
Atlantic
Absent
Right
60650
4 Sig Figs

64. How many significant figures?
The Rules of Zero
How many significant figures?
Pacific
Present
Left
Atlantic
Absent
Right
900.0
4 Sig Figs

65. How many significant figures?
The Rules of Zero
How many significant figures?
Pacific
Left
Pacific
Present
Left
Atlantic
Absent
Right
Atlantic
Right
733
3 Sig Figs

66. Identify the number of significant figures:
100000
900.0

67. Do Now: Solve for x: x2 – 5 = 29 How many significant figures: 0.00150
18% of 105 is how much?
What units would you measure the volume of a pool in?
Convert from scientific notation: 2.3 x 10-4

68. Calculations with Sig Figs
When you multiply or divide the answer must have has many sig figs as the least precise number.
When you add or subtract the answer must have the same number of digits after the decimal place as the number with the fewest digits after the decimal place.

69. Perform each operation:
103 x 2.0
684.9 x 42.3
300 / 50.00
2369 / 3 – –

70. Graphing

71. Graphing Remember to SLAP IT Scale- does your scale cover all data?
Label- did you label each axis with units?
Axis- is your independent variable on the x-axis and your dependent variable on the y-axis?
Plot Points- are all points properly plotted?
Investigate- have you looked for trends and relationships between the variables graphed?
Title!- does your graph have an appropriate title?

72. Reference Table Graphs
There are two graphs you need to be familiar with in your reference table.
They are in Table G: Solubility Curves at Standard Pressure and Table H: Vapor Pressure of Four Liquids.
To be able to read these graphs, you need to first identify which graph will give you the information you need. The title and axis labels will tell if the graph has the information you need.
Now you need to identify the scale used on each axis.
Once these steps are done, use the given information in the problem to determine your missing information.

73. Example What is the solubility of NH3 at 55C?
At which temperature does NaNO3 have a solubility of 100 g solute/100g H20?
Which liquid has a vapor pressure of 150 kPa at 90 C?
At what temperature does water have a water vapor of kPa?

74. Using Graphs
One important piece of information you can use from a linear graph is the slope.
To find slope, use the formula:
Slope = y2 – y1
x2 – x1
Example:
Find the slope of this graph: