AP Chemistry Exam Question of the Week
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Transcript of AP Chemistry Exam Question of the Week
AP Chemistry Exam Question of the Week
Lab safety glasses are NOT needed for which of the following?a). Weighing samplesb). Boiling waterc). Distilling alcohold). Pre-lab write-upse). Titrations
Matter
Does it really matter?
Physical And Chemical Properties
Physical PropertiesDensityMalleabilityDuctilityConductivity
Chemical PropertiesKind of chemical changes that material can undergo
Physical And Chemical Changes
Physical ChangesShapeSizeColorBoiling water or freezing water
Chemical ChangesChange in the identity of the material
Rust
Pure Substances vs. MixturesPure Substance
One type of matterCan be separated into more than one pure
substance but only by chemical changeMixtures
Can be separated into 2 or more pure substances by physical change
2 typesHeterogeneous Homogenous
Elements and Symbols Element
Pure substance that consists of only one kind of atom Examples
Atoms Basic particles that make up elements Consists of positive particles called protons, negative particles called electrons and neutral particles
called neutrons Ions
Protons and electrons = each other in the atom the atom has a neutral charge When protons and electrons are unbalanced atom is charged and is considered an ion
Molecules Atoms by themselves in their natural state are called monatomic elements. These are rare. Examples Elements whose atoms naturally bond into 2 atom units are called diatomic elements. Examples Distinct groups of atoms bonded together are called molecules.
Chemical Symbol Each element has its own unique chemical symbol and name Usually the symbol is based on the name but it might be its Latin or Greek name
Colors- Iridium (Latin for rainbow) People- Curium (for Pierre and Marie Curie) Places- Californium Heavenly bodies- Helium (Helios which is the Greek word for sun) Miscellaneous- Bromine from the Greek word for stench
Compounds and Their Formulas Compounds
2 or more elements chemically combined Some form distinct particles called molecules Other form vast crystalline arrays that repeat called formula units
Chemical Formulas Used to represent the millions of kinds of molecules or formula units that make
up compounds Molecule or formula unit has a definite number of atoms Chemical formulas indicate the number of atoms in each molecule or formula
unit Chemical Subscripts
Small number written at the lower right of a chemical symbol Tells the number of atoms or moles (groups of atoms) in a chemical formula Subscript outside of parenthesis- number of molecules of that entire group Coefficient- in front of the entire chemical formula in a chemical equation. This
number applies to the entire chemical formula and it is the number of molecules of the formula
Energy and Matter Energy
Ability to do work Correlation between energy expended and work done (Physics)
Types of Energy Potential energy Kinetic energy Thermal energy
Energy of atoms as they move around Sound energy
Energy of periodic waves Electrical energy
Forces that mover electrically charged particles Electromagnetic energy
Electric energy that makes magnetic fields Chemical energy
Energy when atoms bond into new compounds Nuclear energy
Split the atom or removing particles from the nucleus Conservation of Energy
Thermodynamics- we will study in greater detail in Chapter 13 Temperature, Heat, Thermal Energy
Kinetic energy= 1/2mv2 Internal energy = KE + PE Temperature = average KE of its particles
TemperatureA measure of the average kinetic energyDifferent temperature scales, all are
talking about the same height of mercuryDerive a equation for converting ºF to ºC
0ºC 32ºF
0ºC = 32ºF
100ºC 212ºF
100ºC = 212ºF
0ºC 32ºF
0ºC = 32ºF
100ºC 212ºF0ºC 32ºF
100ºC = 212ºF0ºC = 32ºF100ºC = 180ºF
100ºC 212ºF0ºC 32ºF
100ºC = 212ºF0ºC = 32ºF100ºC = 180ºF1ºC =
(180/100)ºF1ºC = 9/5ºF
100ºC 212ºF0ºC 32ºF
100ºC = 212ºF0ºC = 32ºF100ºC = 180ºF1ºC =
(180/100)ºF1ºC = 9/5ºF
For every °C there is 9/5 (or 1.8) °F, but the Fahrenheit scale starts out 32° higher than the Celsius scale, so you must add 32 to any Celsius reading and subtracted from any Fahrenheit reading to correct for the starting point differences. The final formulas for converting from F to C or C to F: (5/9 X °C) + 32 = F or 9/5(°F-32) = C
5/9 °C = 1°F
State of Matter 4 States of Matter
SolidLiquidGasPlasma
Changes in the Common States of MatterCondensationVaporizationFreezeMeltSublimationDeposition
Measurement and Metrics
How we measure in science class
TERMS of MEASUREMENT Dimension
Quantities such as length, mass, volume, etc. Unit of measure
Either in English or Metric Scale Calibrated
Scales are calibrated to make sure they are accurate Instrument
Artificial device made for the purpose of refining, extending, or substituting for human senses when measuring.
Metric Vs. English Units
English Units Based on Divisions of 8 or 12 Have multiple units for the
same measurement Length Weight or mass Volume Speed
Metric Units Based on division of 10 Have one unit with prefixes
for the same measurement Length Weight or mass Volume Speed
Metric Prefixes in Chemistry
Prefix Symbol Means Number FormTera T Trillion 1,000,000,000,000 1012
Giga G Billion 1,000,000,000 109
Mega M Million 1,000,000 106
Kilo k Thousand 1,000 103
Hecto h Hundred 100 102
Deka da Ten 10 10
Deci d Tenth 0.1 10-1
Centi c Hundredth 0.01 10-2
Milli m Thousandth 0.001 10-3
Micro µ Millionth 0.000001 10-6
Nano n Billionth 0.000000001 10-9
Pico P Trillionth 0.000000000001 10-12
SI Base UnitsSI Base Units
Dimension Dimension Symbol Si Unit Unit
SymbolLength l Meter m
Mass m Kilogram kg
Time t Second s
Temperature T Kelvin KNumber of particles n Mole mol
Electrical current I Ampere A
Light intensity IL Candela cd
Conversion Factors Unit conversion
Converting from one unit to another with the aid of a… Conversion factor
Fraction that contains the original unit and its equivalent value in a new unit
1L = 1000 mL the conversion factor for converting Liters into mL is 1000mL/1L and the conversion factor for converting mL into L is 1L/1000mL
Bridge Notation Special notation for multiplying and dividing several
measurements together at the same time Can (and will) be used to do any calculations but most often
is used when converting units. Examples of bridge notation