1. Ch 10 Mole Previous Knowledge

2. Scientific Notation
Scientist use it becuase deal with extremely small or extremely large numbers
Has two parts: N x 10n
N: number between 1-10
10n: exponent of 10
Positive exponents for large numbers
Negative exponents for small numbers

3. Positive Exponents
2.53 x 106
Move decimal point to the left until only one nonzero digit is to the left of the decimal point
Convert to scientific notation

4. Negative Exponents
6.43 x 10-4
When converting a number that requires the decimal to be moved to the right, the exponent is decreased by the appropriate number.
Change to scientific notation

5. Operations with Scientific Notation
Addition & Subtraction
The exponents must be equal
Move decimal to left to increase exponent
Move decimal to right to decrease exponent
Multiplication
Only the decimal portion is multiplied
The exponents are added
Division
Only the decimal portion is divided
The exponents are subtracted

6. Significant Figures All nonzero figures are significant.
When a zero falls after the decimal point and after a significatn figure, that zero is significant.
When a zero falls between significant figures, the zero is also significant
When a zero is used merely to indicate the position of the decimal, it is not significant.
All counting numbers and exact numers are treated as if they have an infinite numbers of significant figures.

7. Calculations with Significant Figures
To add or subtract measurements, first perform the mathematical operations, the round off the result to the least precise value.
To mutiply or divide measurements, first perform the calulation, then round the answer to the same number of significant figures

8. Dimensional Analysis
The dimensions of a measurement refer to the type of units attatched to a quanity
Dimensional analysis is the process of solving agebraic equations for units as well as numbers
Its a way of checking to ensure that you have used the correct equation

9. Dimensional Analysis Example
A sculpture is made of aluminum. The density (D) of aluminum is 2700 kg/m3. Determine the mass (m) of a piece of aluminum of volume (V) 0.20 m3.

10. Prefix
Symbol
Exponential Notation
Peta P
1015
Tera T
1012
Giga G
109
Mega M
106
Kilo k
103
Hecto h
102
Deka da
101
Base Unit
100
Deci d
10-1
Centi c
10-2
Milli m
10-3
Micro μ
10-6
Nano n
10-9
Pico p
10-12
Femto f
10-15

11. Unit Conversions Example
One mole of manganese (Mn) has mass of g. How many atoms are in 2.0 mol of manganese?

12. HOMEWORK
P 949 – 959 #1 – 16