Review
Jan 15, 2016
Review
Various models of the atom
• Dalton’s – “billiard ball” model• Thomson – “raisin bun” model• Rutherford – “Electron Cloud” model• Bohr – best model to date
Molecular Elements
• Elements ending in –gen are diatomic.
Pg. 33 – should know this table
Changes
Pg. 47
Classifying Chemical Reactions
Pg. 58
Significant Digits
• Precision is the place value of the last measurable digit and is determined by the instrument
• 12.0 g vs 12 g vs 10 g• Non-zero numbers are significant• Zeros to the left are not significant• Zeros to the right are significant
Compounds
• Valence Electrons• Lewis Symbols• Electronegativity• Types of Bonds• Bonding Capacities
Pg. 88
Predicting Shape Summary
Rules of polar and nonpolar
Electronegativity Differences
Pg. 100
Summary
• Intermolecular forces are the attraction and repulsion of positive and negative charges
• All molecules have London forces – with momentary diploes
• Polar molecules have dipole-dipole forces• Hydrogen bonding occurs when a hydrogen is
attracted to the lone pair from an adjacent molecule
• IMF affect many various physical properties
Physical properties
• While solid has definite shape and volume; it does have various other properties that can be very different. Such as density, colour, melting points, etc
Pg. 119
Summary
Unit Test Review Summary
• Lewis Formulas• Bonding Theory (types)• Electronegativity • Molecular Formulas (Lewis, structural, sterochemical) • Bonding capacity• VSEPR• Bond and molecular Polarity• Intermolecular Forces
– Isoelectronic Compounds• Boiling points• Properties of Liquids and Solids
Units
Pg. 149
Summary
• STP: 0 ˚ C and 101.325 kPa• SATP: 25 ˚ C and 100. kPa• 101.325 kPa = 1 atm = 760 mm Hg• T (K) = t (˚ C) + 273
P= constant
P1V1 = P2V2
V1 / T1= V2/ T2
Properties of Gases• Kinetic molecular theory explains a lot about
the properties of gases– Gases are compressible - the distance between
the molecules– Gas pressure – the amount of collisions that occur– Boyle’s Law– Charles’ Law
Ideal Gas Law
• If we recall Boyle’s Law • Charles’ Law • Avogadro’s theory• Can combine all these to give:
• - constant• -universal gas constant
Solvent and Solute
• Solvent – The component of the solution present in greater amount. Solvent dissolves the solute
• Solute – The component of the solution present in lesser amount. The solute is dissolved by the solvent.
Acids and Bases
PG 199
Summary
Strength of AcidsStrong Acids: ionize (splits up into ions) almost 100% in
water mostly ions in solution amount of HCl present is negligeable
HCl(aq) H+(aq) + Cl-(aq)
Weak acids: ionize poorly in water not many of these ions present in solution mostly acetic acid (HC2H3O2)
HC2H3O2(aq) C2H3O2-(aq) + H+(aq)
NOTE: strong acids are strong electrolytes and will conductelectricity better than weak acids.
pH < 7 acidicpH = 7 neutralpH > 7 basic
• Expressing hydronium concentrations in scientific notation isn’t very convenient. The pH scale was developed to make the expression of H3O+ concentration more convenient.
• [H3O+] is the concentration in mol/L
pH = -log[H3O+]
• Back of book
Net Ionic Equations
• The chemical reaction equation can be written with just the chemicals which will react and form precipitates.
Applications of Stoichiometry
• To determine the overall experiment the percent yield is used.
• This lets us know about the experimental uncertainties– Measurements, purity, washing, estimations
Summary
Limiting Reactions
• There is only a certain amount of one of the reacting chemicals and when all of it is used up the reaction stops – this is the limiting reagent
• The other reactant is more abundant and is called the excess reagent
Limiting and Excess Reagent
• Having a reactant with excess means that more of the substance is present then required for the reaction.
• We our purposes we will use the value of 10 % for the excess amount required to make the reaction occur.
• Sample problem 8.1 pg 320
Interpreting Titration pH Curves
Pg. 334