Chapter 1 Matter Energy and Measurement Chemistry The study of matter information properties and behavior Central Science Microscopic realm Can use senses to study Submicroscopic realm Can t use senses have to use instruments Physical Change Change in appearance or in state no change in composition Chemical Change Composition change breaking forming bonds Physical Properties Describe senses density melting boiling point observed or measured without changing the identity Chemical Properties Chemical reactions dissolving burning rust Exothermic releases energy driving Endothermic absorb energy photosynthesis Observations of matter 1 The matter in the universe consists of many different forms 2 Matter is found in three primary states a Solid definite shape and volume rigid b Liquid definite volume non rigid flows c Gas takes on shape and volume of container non rigid flows 3 Most can be decomposed Substances Element simplest purest form of a substance can t break down 90 naturally occurring rest are synthetic 28 unstable Allotropes Exists in more than one form in nature Compound Always same ratio of elements properties are usually different from those that make it up Pure Substances Atoms consists of one type of element or Molecules can consist of more than one type of element Mixture More than one atom element or compound are found together Heterogeneous mixture not uniform throughout Homogenous mixture uniform throughout Solutions Dissolved in something else at atomic level Significant Figures All the ones we know plus one uncertain one Significant Figures Rules unit of measurement least certain original number When multiplying or dividing sig figs are limited by the smallest amount of digits in a When adding or subtracting the answer cannot have more digits after the decimal than the Zeros in middle of digits are significant Zeros at beginning are insignificant Zeros at the end and after a decimal point are significant Zeros before an implied decimal may or may not be significant Only round at the end of a problem follow rule for last operation Conversions Thousand Tenth Hundredth Thousandth Millionth Billionth k d c m ua n 10 3 10 1 10 2 10 3 10 6 10 9 Kilo Deci Centi Mili Micro Nano Conversion factor a ratio including units used as a multiplier to change from one system to another Volume L Space that is occupied by a solid liquid or gas 1cm 3 1mL 1mL 1 1000L 10cm 1dm 1dm 1 10m 1L 1dm 3 1000cm 3 Mass The quantity of matter in an object independent of location 1kg 1000g 1mg 001 g Kelvin Scale Absolute scale 0K is absolute zero no movement Density A constant physical property at a given temperature 0K 273 15 degrees C D mass volume Energy The capacity to work Energy Kinetic energy Moving energy Potential energy Stored energy Chemical Heat Most frequently accompanies chemical rest total energy in a substance Calorie cal amount of energy required to raise the temp of 1g h2o 1d C Joule J 1 cal 4 184J Temperature How fast molecules are moving Specific heat Energy required to raise the temp of 1g of a substance 1K KE 1 2 mv2 Mechanical Light Heat Electrical Units Chapter 2 Atoms In order of discovery Electron e Smallest so not counted in atomic weight Proton p Neutron n Atomic number of protons in each atom of an element Mass number of protons and neutrons Isotopes Atoms of the same element that contain different number of neutrons Masses will be different Physical properties may be different Some are unstable Shell Model Outer shell is the valence shell Luis Dot Structure Electron Shielding Valence electrons are shielded from some of the effective nuclear charge Ionization energy The energy required to remove an electron from the valence shell The stronger the effective nuclear charge the stronger Ionization energy Atomic radius Inversely proportionate to the Ionization energy Elements show periodicity Cyclical Group 1A Alkali Metals Croup 2A Alkaline earth Metals Group 7A Halogens Group 8A Noble Gasses Quantum Mechanical Model Numbers used to describe an orbital Map out the probability of locating the electron S Orbitals P Orbitals D Orbitals Octet rule valence shell Chapter 3 Ionic Compounds Cation Positive charge loss of electron Anion Negative charge gain electron Ion An atom or molecule that has an electric charge due to an imbalance of electrons to protons A chemical reaction to achieve stability to get configuration of nearest noble gas a full Molecular compound Consist of neutral molecules Ionic compound positive and negative ions Aqueous dissolved in water Electrolytes Liquids that conduct electric currents Jumps from cation to cation Monoatomic individual atom with a positive or negative charge Polyatomic Molecules with an overall charge act as one unit Polyatomic Ions Ammonium NH4 Hydroxide OH Nitrate NO3 Bicarbonate HCO3 Carbonate CO3 2 Sulfate SO4 2 Phosphate PO4 3 Cyanide CN Transition metals Can t predict how many electrons they will give or take Monoatomic type II write with roman numerals Empirical Formula Simplest ratio of an atom Write cation first without charges Anion gets ide suffix Chapter 4 Covalent Compounds Closer elements share electrons Makes them more stable o Internuclear forces Distance between their nuclei o When they get too close they repel Bond is two shared electrons o Atoms not shared are lone pairs Molecular formula A formula with the number of atoms of each element that is present Tools to Predict Bonding 1 Valence Electron Inventory Add all electrons of all molecules together Add an electron for each and subtract one for each 2 Draw the skeleton for the model 3 Use maintaining electrons to satisfy the octet rule for each atom 4 5 Place any remaining electrons on central atom Least If insufficient use multiple bonds electronegative Electron Geometry e Linear Molecular Geometry m Linear Trigonal Trigonal Bent Angle Degrees 180 120 120 Tetrahedral 109 5 Trigonal P 109 5 Bent 109 5 Tetrahedral 0 0 1 0 1 2 Molecular and Electronic Shape Electron Clouds Bonded Atoms Lone Pairs 2 3 4 2 3 2 4 3 2 Dipole Electron rich Electron poor Polar bond a bond with a positive a negative dipole creating an overall dipole Based on Electronegativity Electronegativity Depends on the number of electron how full the octet is Fluorine has highest everything goes down from there Boiling Points Ionic Compounds High melting and boiling points Molecular Compounds Low melting and boiling points rarely soluble non conductive Like Dissolves Like o Things that are polar