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