Chemistry Regents Review

Solid

Strong Forces, High Density, Low Energy

Liquid

Medium Forces, Low Density, Medium Energy

Gas

Weak Forces, Very Low Density, High Energy

• Density

• Color

• Odor

• Hardness

• State of matter

• No new substance

Physical Properties

• fire

• React

• Neutralize

• Combust

• New substance formed

Chemical Properties

Pure Substance

matter that has uniform and definite composition

Homogeneous

pure substance distributed evenly throughout the mixture

Heterogeneous

substances not evenly mixed

Law of Conservation of Energy

Energy can not be created nor destroyed, input = output

Temperature

Measure of Average Kinetic Energy

Endothermic Energy Change

Requires heat, heat on the left side of equations

Exothermic Energy Change

Produces heat, heat of the right side of equations

Heat Flow

High —> Low

Plum Pudding

Thompson

Bowling Ball/Solid Sphere

Dalton

Gold Foil Model

Rutherford

Planetary

Bohr

Proved existence of neutrons

Chadwick

Diffuse clouds around nucleus

Quantum Mechanical Model

Nucleus

Dense, positively charged, center of atom

Isotope

Atoms with the same number of protons, different number of neutrons

Elements are defined by their number of

protons

Isotopes are defined by their number of

neutrons

Isotope similarities

Chemical properties, atomic numbers, number of electrons

Isotope differences

Number of neutrons, mass numbers

Electrons closer to the nucleus

less energy

Electrons father from the nucleus

more energy

Represents number of valence electrons

Lewis Dot Diagrams

Chemical changes are caused by

competitions for valence electrons

Alkali Metals

Group 1

Alkaline Earth Metals

Group 2

Transitional Metals

Groups 3-12

Halogens

F, Cl, Br, I

Diatomic 7

N, O, F, Cl, Br, I, H

Liquids at STP

Br and Hg

Noble Gases

He, Ne, Ar, Kr, Xe, Rn

Gasses at STP

Noble Gases and N, O, F, Cl, H

Anion

smaller, electrons > protons, non-metals, negative

Cation

larger, electrons < protons, metals, positive

Ionic Bond

Metal and Non-Metal

Covalent Bond

Non-Metal and Non-Metal

Metallic Bond

Metal and Metal

Bond formation is

exothermic

Bond breakage is

endothermic

Ionic Naming

Metal first, non-metal becomes -ide

Ionic compounds form

ionic crystals

• MP/BP: High

• Crystalline Structure: Hard

• Solid Conductivity: Poor

• Aq/L Conductivity: Good

Ionic Compound Properties

Empirical Form

simplest ratio of elements

• MP/BP: Low

• Shared electrons

• (Thus) Weaker Bonds

• Not conductive

• Overall Charge = 0

Covalent Compound Properties

Covalent Naming

Use prefixes (Table P), last ends in -ide

• 2 elements

• Metal and Non-Metal

• -ate, -ite, -ium

• Table E

Binary Ionic

• 3+ elements

• Attraction of ions of opposite charge

• Covalent bonds inside Polyatomic ion

Ternary Ionic (Polyatomic)

Law of Conservation of Mass

Matter can not be created nor destroyed

1 mol

6.022 × 10²³

Amu

Mass of one element in grams

1. Assume 100g or 1000g sample

2. g —> mol (dimensional analysis)

3. Divide moles by smallest # of moles

   1. Empirical formula

4. Determine molecular mass of empirical formula (multiplier)

Empirical and Molecular Formula

1. Plug both given values in to get desired value

2. Lesser desired value is limiting reagent

   1. must use this value

   2. also theoretical value

Limiting Reagent

((amount you got) / (given or value you should have gotten/theoretical value)) * 100

Percent Yield

Coefficients of a substance are equal to the

number of moles of that substance

Fastest Particles @ STP

Gas, Liquid, Solid

“Fluid” Substances

Gases and Liquids

Only compressible particles

Gas particles

Heat is dependent on

sample size (mass)

Faster moving particles mean

higher temperatures

(Temperature) particle motion is

random

Sample size/mass has no effect on

temperature

Intermolecular Forces

Attraction between particles/molecules

Viscosity

resistance to flow

As heat is removed from a gas

avg KE decreases, particle attraction increases

As heat is added to a gas

avg KE increases, IMFs decrease

Melting a substance

weakens IMFs

Boiling a substance

completely breaks IMFs

Ideal Gas Law

PV = nRT

• Random, continuous motion

• No attractive forces

• elastic collisions

• volume is negligible

Ideal Gases

• Have mass

• Have attractive forces

Real Gases

Real Gases behave like Ideal gases under these conditions:

• High Temp

• Large Volume

• Low Pressure

Vapor Pressure

• A measure of the tendency of a material to change into gaseous or vapor state

• Increases with temp

• Strong IMFs when low

• Weak IMFs when high

A + B —> AB

Synthesis

AB —> A + B

Decomposition

AB + C —> AC + B

Single Replacement

AB + CD —> AD + CB

Double Replacement

Equilibrium

Forward and backward process rates are the same/equal. Must be a reversible, closed system. Amounts of products and reactants must be constant.

Reactions require

effective collisions

More collisions

• faster reactions

• increased reaction rate

• decreased reaction time

Less collisions

• slower reactions

• decreased reaction rate

• increased reaction time

Other collision factors

• frequency of collisions

• how hard they collide

• angle of impact

• High Temp

• High Surface Area

• High Concentration

• Catalyst

  • Straightens out collision

• Reactant Nature (fast —> slow)

  • Ionic

  • Gases

  • Liquids

  • Solids

Ideal Conditions for Collisions

Free Element

Oxidation state of 0

Compound charges always add to 0

1. Group 1 metals always +1

2. Group 2 metals always +2

3. Fluorine always -1

4. Hydrogen +1

5. Oxygen -2

6. Cl, Br, I in Binary Ionic Compound: -1

7. Polyatomic Ions add to their charge

1. Assign Oxidation #’s

2. Did #’s change during reaction

   1. Yes: Redox

   2. No: Not Redox

3. Who gained (red) and who lost (ox)

Redox Reaction Steps

What catalysts do (PE + Enthalpy)

Lowers the activation energy (flattens the curve)

• + Delta H

• PE_P > PE_R

• Not fun roller coaster

• A + B + heat —> C + D

Endothermic PE Curve

• - Delta H

• PE_P < PE_R

• Fun rollercoaster

• A + B —> C + D + heat

Exothermic PE Curve

• S —> L —> A —> G

• More particles/moles

• Increase temp

How to increase entropy

Entropy

the disorder created by everything

Solute

dissolved particles in a solution

Solvent

the dissolving medium in a solution

Saturated

a solution containing the maximum amount of solute for a given amount of solvent at constant temperature and pressure

• must be soluble in water

• forms ions in solution by disassociation

• Conducts electricity in liquid and aqueous states

  • B/c ions are mobile in water

• Must be charged

Electrolytes