1. Scientific Notation Significant Figures Conversion Factors

2. Bell ringer answer the following in your notebook
What is the metric System?
Susan conducts an experiment five times and gets a solution concentration of 1.9M, 2.1M, 1.8M, 1.9M, and 2.2M. The known concentration of the solution is 2.0M. Which of the following are true about Susan's results?
They are precise, but not accurate.
They are accurate, but not precise.
They are both accurate and precise.
They are neither accurate nor precise.

3. Metric Measurement
Metric System – The standard measurement system used by scientists around the world. Also called the International System of Units, or SI. It is a decimal system, based on the number 10 and multiples of 10.

5. Uncertainty in Measurement
Uncertainty comes from limitations of measuring devices, experimental design, experimenter, and nature’s random behavior.
Accuracy – how close a measurement comes to the actual value.
Precision – how close measurements are to one another, or how reproducible they are.
Not Accurate and Not Precise
Accurate but Not Precise
Not Accurate but Precise
Accurate and Precise

6. For example 54 000 can be expressed as 5.4 x 104
Scientific Notation
For example can be expressed as 5.4 x 104
in scientific notation, and the number
can be expressed as
8.765 x 10-6.

7. The base is always between 1 and 9.99
As the preceding examples show, each value expressed in scientific notation has two parts.
The base is always between 1 and 9.99
(less than 10)

8. To write the first factor of the number, move the decimal point to the right or left so there is only one nonzero digit to the left of it.
Examples
5467

9. The second part is raised to an exponent of 10.
The exponent is determined by counting the number of places the decimal point must be moved. If the decimal point is moved to the left, the exponent is positive. If the decimal point is moved to the right, the exponent is negative.

10. Examples Express each of the following in scientific notation. 67 000

11. Examples
Express each of the following in standard form. 8.2 x x 10-6
8200

12. Examples
1.775 x 107
7.065 x 10-5

13. Percent error

14. Significant Figures
Significant figures let other people know just how good the measurement is!

15. Significant Figures 99,000 2 sig figs 99,000. 5 sig figs 0.0099
Examples: How many significant figures?
99,000
2 sig figs
99,000.
5 sig figs
0.0099
2 sig figs
0.0990
3 sig figs

16. Do Not Count Sig Figs When
Using standardized values Or Molar Mass from the periodic table

17. Calculating with Significant Figures
When you use your measurements in calculations, your answer may only be as exact as your least exact measurement.
For addition and subtraction, round to the fewest decimal places.
Example: (3 decimals) (1 decimal) (unrounded) (rounded) =
67.7
For multiplication and division, round to the fewest significant figures.
Example: (3 sigfigs) (1 sigfig) (unrounded) (rounded) x = 3

18. Conversion Factors
A conversion factor is a ratio derived from the equality between two different units that can be used to convert from one unit to the other! Remember that solving a chemistry problem is like taking a trip.

19. How am I going to get there?
Ask yourself
Where am I?
Where am I going?
How am I going to get there?

20. Neuroplasticity Break

21. Conversion Factor Examples

22. More Examples

23. Examples
1 kilogram = 1000 g

24. Use conversion factors to convert each of the following
612 dollars to quarters
1 dollar = 4 quarters

25. 537 dollars to nickels
1 dollar = 20 nickels
537 dollars x

26. Double Conversion!!!!!! 7 days to minutes 1 day = 24 hours
1 hour = 60 minutes

27. 177 millimeters to meters
1 millimeter = 0.001meter

28. 32 kilograms to milligrams
Double Conversion!!!
1 kilogram = 1000 grams
1 milligram = gram

29. 3.4 liter x 3400 mL 6. 3.4 liter to milliliters
1 millimeter = meter
1 milliliter = liter
3.4 liter x
3400 mL

30. Neuroplasticity Time
Now take out your practice problems.