2Scientific NotationNumbers that are extremely large can be difficult to deal with…soooScientists convert these numbers into scientific notationScientific notation expresses numbers as a multiple of two factors:A number between 1 and 10 (only 1 digit to the left of the decimal!)Ten raised to a power
3For example:A proton’s mass = kgIf you put it in scientific notation, the mass of a proton is expressed as x kgRemember:When numbers larger than 1 are expressed in scientific notation, the power of ten is positiveWhen numbers smaller than 1 are expressed in scientific notation, the power of ten is negative
4Try these: Convert 1,392,000 to scientific notation. = 1 Try these: Convert 1,392,000 to scientific notation. = x 106 Convert 0.000,000,028 to scientific notation. = 2.8 x 10-8
5Adding and Subtracting using Scientific Notation Make sure the exponents are the same!!7.35 x x 102 = 9.78 x 102If the exponents are not the same, you have to make them the same!!Tip: if you increase the exponent, you decrease the decimal if you decrease the exponent, you increase the decimalExample:Tokyo pop: x 107Mexico City pop: x 106 = 1.56 x 107Sao Paolo pop: x 108 = 1.65 x 107NOW you can add them together and carry thru the exponentTotal= 5.91 x 107
6Multiplying and Dividing using Scientific Notation Multiplication:Multiply decimals and ADD exponentsEx : (1.2 x 106) x (3.0 x 104) = 3.6 x = 10* Ex: (1.2 x 106) x (3.0 x 10-4) = 3.6 x (-4) = 2Division:Divide decimals and SUBTRACT exponentsEx: (5.0 x 108) ÷ (2.5 x 104) = 2.0 x – 4 = 4*Ex: (5.0 x 108) ÷ (2.5 x 10-4) = 2.0 x – (-4) = 12
8Units of Measure SI units: Systeme Internationale d’ Unites standard units of measurement to be understood by all scientistsBase Units: defined unit of measurement that is based on an object or event in the physical worldthere are 7 base unitssome familiar quantities are time, length, mass, and temp
9Timesecond (s)Many chemical reactions take place in less than a second so scientist often add prefixes, based on multiples of ten, to the base units.ex. MillisecondLengthmeter (m)A meter is the distance that light travels though a vacuum in 1/ of a second.What is a vacuum?Close in length to a yard.Prefixes also apply…ex. millimeter
10Mass mass is a measurement of matter kilogram (kg) about 2.2 pounds Masses measured in most laboratories are much smaller than a kilogram, so scientists use grams (g) or milligrams (mg).How many grams are in a kilogram?1000How many milligrams are in a gram?
11Derived Units Not all quantities are measured in base units A unit that is defined by a combination of base units is called a derived unit.Volume and Density are measured in derived units.
12VolumeThe space occupied by an objectUnit = cm3 = mLLiters are used to measure the amount of liquid in a container (about the same volume as a quart)Prefixes also applied…ex. milliliter
13Modified Table 2.1 – The Base Units QuantityBase UnitTimeSecond (s)LengthMeter (m)MassKilogram (kg)TemperatureKelvin (K)Amount of a substanceMole (mol)Electric currentAmpere (A)Luminous intensityCandela (cd)
14Modified Table 2.2 – SI Prefixes SymbolNumerical Value in Base UnitsPower of 10 EquivalentGigaG1,000,000,000109MegaM1,000,000106KiloK1000103--1100Decid0.110-1Centic0.0110-2Millim0.00110-3Micro10-6Nanon10-9Picop10-12