PreAP Chemistry Chapter 2 Notes

PreAP ChemistryChapter 2 Notes

Turn Chapter 2 Preview Questions into the white box before you sit down.Why use the metric system?

40 rods = 1 furlong1 furlong = 10 chains1 chain = 66 feet2 Mouthfuls = 1 Jigger2 Jiggers = 1 Jack2 Jacks = 1 Gill2 Gills = 1 Cup2 Cups = 1 Pint2 Pints = 1 Quart`2 Quarts = 1 Pottle2 Pottles = 1 Gallon

2 Gallons = 1 Peck2 Pecks = 1 Doublepeck

2 Doublepecks = 1 Bushel2 Bushels = 1 Cask

2 Casks = 1 Barrel2 Barrels = 1 Hogshead

40 Rods = 660 feet1 Hogshead = 64 gallonsSo:

40 Rods1 Hogshead=

10.3 feetgallonUnits of MeasurementHorses are measured in hands. This used to literally mean how many hand widths to go down the side of the horse. For someone with small hands their horses will seem bigger than someone with big hands.

Units of MeasurementHorses are measured in hands. This used to literally mean how many hand widths to go down the side of the horse. For someone with small hands their horses will seem bigger than someone with big hands.To avoid these issues in science, scientists have adopted SI Units. (SI = Systme International, French for International System.) These base units have been agreed on by the scientific community and will be used in this class.QuantityQuanitity Symbol Base Unit NameAbbreviation LengthlmetermMassmkilogramkgVolumeV (uppercase)literL (uppercase)TimetsecondsTemperatureT (uppercase)KelvinK (uppercase, no )Amount ofSubstancenmolemolUnits of MeasurementMass is a quantity of matter and is constant. Do not confuse it with weight! Astronauts on the moon have less weight, but not less mass (less mass would mean they were shrinking!)

1 kilogram is the same mass as 2.204622621849 pounds (but we'll use 2.20 lbs for this course)

Units of MeasurementLength is the distance between two points. 1 inch = 2.54 centimeters (exactly)

Units of MeasurementTemperature is the measurement of heat intensity (more about this later).1 Kelvin is the same magnitude as 1 C 0 C = 273.15 K

Units of MeasurementA mole is a count of something, like a dozen. By definition this is an exact count and not a measurement, but of course no one can count six hundred two sextillion two hundred fourteen quintillion one hundred and fifty quadrillion, so the number is determined mathematically. The best calculation is currently 602,214,150,000,000,000,000,000. Most often for this course the rounded off number below will be used. 1 mole = 6.022 1023 particles or things Units of MeasurementThe beauty of the SI units is that almost all of them can be scaled up or down by factors of ten with relative ease. Often once this is done a new prefix is added to base unit to indicate the new unit of measurement. You will need to understand and be able to use these prefixes for this course. Be sure to note which abbreviations use lowercase and uppercase letters! This distinction is very important. For example m and M are two different orders of magnitude. Metric PrefixesLarger than 1:Smaller than 1:prefixmeaningprefixmeaningyottaseptilliondecitenthzettasextillioncentihundredthexaquintillionmillithousandthpetaquadrillionmicromillionthteratrillionnanobillionthgigabillionpicotrillionthmegamillionfemtoquadrillionthkilothousandattoquintillionthhectohundredzeptosextillionthdekatenyoctoseptillionth

Prefix and SymbolAmount ofPrefixAmount of base unitAmount ofPrefixMega (M)1 M_=1,000,000 _Kilo (k)1 k_=1,000 _Hecto (h)1 h_ =100 _Deka (da or dk)1 dk_ =10 _Base Units1 _Deci (d)1 _=10 d_Centi (c)1 _=100 c_Milli (m)1 _=1,000 m_Micro ()1 _=1,000,000 _Nano (n)1 _=1,000,000,000 n_Prefix and SymbolAmount ofPrefixAmount of base unitAmount ofPrefixMega (M)1 M_=1,000,000 _Kilo (k)1 k_=1,000 _Hecto (h)1 h_ =100 _Deka (da or dk)1 dk_ =10 _Base Units1 _Deci (d)1 _=10 d_Centi (c)1 _=100 c_Milli (m)1 _=1,000 m_Micro ()1 _=1,000,000 _Nano (n)1 _=1,000,000,000 n_Quiz over these on Monday.Memorize these!

Units of MeasurementDerived units are new units that are made by combining two or more of the standard units together. Below are several derived units, how they are derived, and the usual SI units used with each. There are many, many more derived units. Derived UnitOriginUsual SI UnitsDensityMass per unit volumeg/m3 = g m-3 org/cm3 = g cm-3 org/L = g L-1 org/mL = g mL-1Volumelength width heightL or m3 or cm3PressureForce per unit areaPascals (Pa)

Units of MeasurementConversion factors are a ratio derived from the equality between two different units that can be used to convert from one unit to the other. For example:4 quartersor1 dollaror even0.25 dollars1 dollar4 quarters1 quarterUnits of MeasurementConversion factors allow a quantity measured one way to be converted into a different way of measuring (although the overall amount should never change). Sometimes several conversion factors are used in the same calculation, but it is important to note that units in the numerator will cancel with identical units in the denominator. This process is called the factor label method or dimensional analysisUnits of MeasurementFor example:How many quarters are in 6.53 dollars?6.53 dollars 4 quarters = 26.12 quarters 1 dollar Units of MeasurementA) How many centimeters are in 2.34 miles?2.34 miles Units of MeasurementA) How many centimeters are in 2.34 miles?2.34 miles mile Units of MeasurementA) How many centimeters are in 2.34 miles?2.34 miles 5280 feet 1 mile Units of MeasurementA) How many centimeters are in 2.34 miles?2.34 miles 5280 feet 1 mile Units of MeasurementA) How many centimeters are in 2.34 miles?2.34 miles 5280 feet 1 mile foot Units of MeasurementA) How many centimeters are in 2.34 miles?2.34 miles 5280 feet 12 inches 1 mile 1 foot Units of MeasurementA) How many centimeters are in 2.34 miles?2.34 miles 5280 feet 12 inches 1 mile 1 foot Units of MeasurementA) How many centimeters are in 2.34 miles?2.34 miles 5280 feet 12 inches 1 mile 1 foot inch Units of MeasurementA) How many centimeters are in 2.34 miles?2.34 miles 5280 feet 12 inches 2.54 cm 1 mile 1 foot 1 inch Units of MeasurementA) How many centimeters are in 2.34 miles?2.34 miles 5280 feet 12 inches 2.54 cm 1 mile 1 foot 1 inch Units of MeasurementA) How many centimeters are in 2.34 miles?2.34 miles 5280 feet 12 inches 2.54 cm = 376,586.496 cm 1 mile 1 foot 1 inch Units of MeasurementB) How many inches per second is 50 miles per hour?50 miles hourUnits of MeasurementB) How many inches per second is 50 miles per hour?50 miles hourhourUnits of MeasurementB) How many inches per second is 50 miles per hour?50 miles 1 hourhour3,600 sUnits of MeasurementB) How many inches per second is 50 miles per hour?50 miles 1 hourhour3,600 sUnits of MeasurementB) How many inches per second is 50 miles per hour?50 miles 1 hourhour3,600 s miUnits of MeasurementB) How many inches per second is 50 miles per hour?50 miles 1 hour5,280 fthour3,600 s1 miUnits of MeasurementB) How many inches per second is 50 miles per hour?50 miles 1 hour5,280 fthour3,600 s1 miUnits of MeasurementB) How many inches per second is 50 miles per hour?50 miles 1 hour5,280 fthour3,600 s1 mi ftUnits of MeasurementB) How many inches per second is 50 miles per hour?50 miles 1 hour5,280 ft12 incheshour3,600 s1 mi1 ftUnits of MeasurementB) How many inches per second is 50 miles per hour?50 miles 1 hour5,280 ft12 incheshour3,600 s1 mi1 ftUnits of MeasurementB) How many inches per second is 50 miles per hour?50 miles 1 hour5,280 ft12 in= 880 inhour3,600 s1 mi1 ftsUnits of MeasurementC) How many kL is 462 L?462 LUnits of MeasurementC) How many kL is 462 L?462 L1 L1,000,000 LUnits of MeasurementC) How many kL is 462 L?462 L1 L1 kL1,000,000 L1,000 LUnits of MeasurementC) How many kL is 462 L?462 L1 L1 kL= 0.000000462 kL1,000,000 L1,000 LUnits of MeasurementD) How many atoms of dysprosium are in 4.539 moles of dysprosium?4.539 moles=Units of MeasurementD) How many atoms of dysprosium are in 4.539 moles of dysprosium?4.539 moles=1 moleUnits of MeasurementD) How many atoms of dysprosium are in 4.539 moles of dysprosium?4.539 moles=1 moleUnits of MeasurementD) How many atoms of dysprosium are in 4.539 moles of dysprosium?4.539 moles6.022 x 1023 atoms=1 moleUnits of MeasurementD) How many atoms of dysprosium are in 4.539 moles of dysprosium?4.539 moles6.022 x 1023 atoms= 2.733 x 1024 atoms1 moleUnits of MeasurementE) How many moles of uranium oxide would contain 5.23 x 1021 compounds of uranium oxide?5.23 x 1021 compoundsUnits of MeasurementE) How many moles of uranium oxide would contain 5.23 x 1021 compounds of uranium oxide?5.23 x 1021 compounds6.022 x 1023 compoundsUnits of MeasurementE) How many moles of uranium oxide would contain 5.23 x 1021 compounds of uranium oxide?5.23 x 1021 compounds1 mole6.022 x 1023 compoundsUnits of MeasurementE) How many moles of uranium oxide would contain 5.23 x 1021 compounds of uranium oxide?5.23 x 1021 compounds1 mole= 2.733 x 1024 atoms6.022 x 1023 compoundsPractice Questions Answers1. 0.06522 g2. 576,000,000,000 ng3. 514.8 s4. 694 cm/s5. 5.3 moles6. 5.2 x 1023 moleculesUsing Scientific MeasurementsUsing Scientific MeasurementsWhen scientists make measurements, there is usually a little discrepancy in the measurements due to many reasons, often human error. For example, the same person could measure a string three different times and get three, slightly-different measurements. For this reason, when making measurements or reading someone elses measurements it is important to consider the accuracy and precision of those measurements.Using Scientific MeasurementsAccuracy refers to how close the measurement is to the real or accepted value. Precision is how close a group of measurements of the same thing are to each other. The precision of a series of measurements is usually easy to determine just by looking at them, but this is not the case with the accuracy.

Game Time!Which is more accurate?

Or

Which is more accurate?

Or

Which is more accurate?

Or

Which is more accurate?

Or

Which is more accurate?

Or

Which is more precise?Using Scientific MeasurementsTo find the level of accuracy of a measurement, the percent error is calculated. To make the calculation the accepted value (the value you were supposed to get) and the value you actually did get during the experiment are needed.Using Scientific MeasurementsThen use this equation:

The label to your percent error is the % sign.Percent error =|Accepted value Experimental value| 100Accepted ValueUsing Scientific MeasurementsFor example; An experiment finds the density of lead to be 10.95 g/cm3. The textbooks states the density should be 11.34 g/cm3. What was the percent error for this experiment?Percent error =11.34 g/cm3 10.95 g/cm3 100 = 3.439 %11.34 g/cm3Practice Question 1-7.04 %

Practice Question 231.6 %