Section 3-1 Dimensional Analysis 1.) Dimensional Analysis or Factor Label: A method used to change from one unit to another. a.) Conversion Factor: numbers that are used to change from one unit to another. (1 inch = 2.54cm, or 12 inches = 1 ft, 1000m = 1km

B.) Metric conversions: i.) use KHDBDCM (King Henry Died By Drinking Chocolate Milk) as conversion factors. a.) KHDBDCM is kilo, hecto, deka, base, deci, centi, milli. ii.) Your given unit should be put in a fraction over the number “1” a.) example: 3461cm  3461cm 1

iii.) the desired unit should be in a fraction in the numerator next to your original fraction, while the original unit should be in the denominator. a.) example continued: 3461cm convert to km 3461cm km 1 cm iv.) next put the numbers from KHDBDCM on the second fraction a.) 3461cm | 1 km 1 | cm

v.) multiply across, divide down. (you may want to make a fence), and cancel the first unit and the denominator in the conversion factor (second fraction) a.) multiply 3461 by 1 and divide by vi.) this number with the new unit is your answer a.) km

vii.) examples: 13.45mL to L, and 0.563g to mg

Section 3-2 Scientific Notation 1.) Scientific Notation: a number is expressed as the product of two factors a.) the first factor is between 1 and 10 b.) the second factor is a power of 10 c.) If a number is smaller than 1, it will have a negative exponent d.) if a number is larger than or equal to 10, it will have a positive exponent e.) If a number is greater than or equal to 1, or less than 10, its exponent will be zero

2.) Rules: a.) make the number have one digit to the left of a decimal place. Count the number of places you must take to do this. b.) write the number X 10 #ofplaces c.) follow rules c,d, and e for the sign of the exponent.

3.) When writing the number from scientific notation: a.) if your exponent is positive, the decimal moves that many places right. b.) If your exponent is negative, the decimal moves that many places left.

4.) Scientific notation follows sig fig rules. a.) When counting the number of sig figs, use scientific notation to help. b.) example: X 10 5 has only 4 sig figs. 400 X 10 2 has only 1 sig fig c.) How ever many sig figs are in a number, put those numbers in scientific notation d.) example Becomes X 10 3 with 4 sig figs e.) example Becomes 4 X 10 5 with 1 sig fig

Section 3-3 Computations with sig figs 1.) Multiplying/dividing: your answer must be rounded to the same number of sig figs as the number with the smallest number of sig figs X = Since the has 3 sig figs, then you must round to 3 sig figs. Making it 279, or 2.79 X 10 2

2.) adding/subtracting: your answer must be rounded to the same decimal place as the number with the fewest number of significant decimal places = However, since has only 1 significant decimal place (the tenths), the number must be rounded to the tenths. So the answer is 312.5

3.) difficult examples (3 X 10 4 )/(1.234 X 10 3 ) 500 X 900