1. Chapter 1
Science Skills

2. Scientific Notation
In science it is very common to work with really large or really small numbers.
602,000,000,000,000,000,000,000
6.02 x 1023 atoms = 1 mole of a substance
_____ x (# of decimal places)
(+….moved left)
Number between (-…..moved right)
1 and 9

3. Rules for Scientific Notation
If the original number is larger than 1, then you move the decimal to the left and your exponent will be positive.
= x 103
* Moved the decimal point 3 places to the left.
If the original number is less than 1, then you move the decimal point to the right and your exponent will be negative.
= x 10-3
*Moved decimal point 3 places to the right.

4. If you take a number out of scientific notation look at the exponent first.
Negative Exponent = move to the left
Positive Exponent = move to the right

5. Try These: A. 43,812g = B. .000000943m = C. 5.66 x 10-3 L =
D x 106 g =
x 104
9.43 x 10-7
.00566
7,254,000

6. Uncertainty in Measurements
Measurements are an important aspect in Chemistry.
Three common measurements that we typically make are for Mass, Volume, and Temperature.
When you make a measurement, write down all the numbers you can. WHY??
Measuring instruments are never completely free from flaws.
Measuring always involves some estimation.
(Digital-Balance or Scale-Graduated Cylinder)
How do you know when a measurement is reliable?

7. Accuracy, Precision, and Error
It is necessary to make good, reliable measurements in the lab
Accuracy – how close a measurement is to the true value
Precision – how close the measurements are to each other (reproducibility)

8. Precision and Accuracy
Precise, but not accurate
Precise AND accurate
Neither accurate nor precise