Chemistry Unit 7

A+B → AB

ex: Na +Cl2 → NaCl

A+B → AB

ex: Na +Cl2 → NaCl

Synthesis

AB → A+B

ex: NaCl → Cl2

Decomposition

AB + C → AC + B

ex: NaBr +Cl2 → NaCl + Br2

single replacement → nonmetal replaces nonmetal

AB + C → CB + A

ex: HCl + Mg → MgCl2 + H2

single replacement → metal replaces metal

AB + CD → AD + CB

ex: NaNO3 + KCL → NaCl + KNO3

double replacement

HA + BOH → H2O + BA

ex: HCl + KOH → H2O + Kl

acid + base → water and salt

neutralization

organic + O2 → CO2 + H2O

ex: CH4 + O2 → CO2 +H2O

organic combustion

metal + O2 → metal oxide

ex: Mg + O2 → MgO

metallic combustion

Oxidation Agents

• Electron acceptor

• Helps the other element be oxidized

  • This is the compound that contains the reduced form.

Reducing Agents

• Electron Donor

• Helps the other element be reduced

  • This is the compound that contains the oxidized form

Oxidation

The element that has an increase in oxidation state (a loss of electrons)

Reduction

The element that has a decrease in oxidation state (a gain of electrons)

Endothermic Reaction → draw graph

• Energy absorbed(used)

• system gets cooler

• Energy needed

  • reactants + heat → product

Exothermic Reaction → draw graph

• Energy Released

• System gets warmer

  • Energy originally stored in + heat

Change in Enthalpy Equation

ΔH = Product - Reactant

Predicting Products (steps)

• Break apart the compound (A2O3 → Al + O)

• Diatomic elements must add a subscript of 2 (Al + O2)

Collision Theory

1. The reactants have to collide

2. the reactants have to collide with each other with enough amount of energy (activation energy)

3. The reactants should have the right orientation (position) when colliding.

How to determine the limiting and excess reactants

1. For each reactant calculate the amount of product formed (moles/grams)

2. the smaller answer indicates the limiting reactants and amount of product formed

   1. The smaller product amount (grams, moles, etc.) is the theoretical yield.

molarity equation

M = mol/L

Formula for dilution

M1V1 = M2V2

Catalysts in chemical reactions

Adding a catalyst can speed up a chemical reaction

• lowers activation energy = collisions are more efficient.

Speeding up chemical reaction (4 ways)

1. Concentration/Molarity (more molecules = more collisions)

2. Temperature (Faster molecule = more collisions)

3. Surface Area (more molecules exposed = more collisions)

4. Catalyst

Acids

• Contain Hydrogen(H+) ions

• Taste sour

• corrosive to metals

• low pH

• conducts electricity in water

  • turns blue litmus paper red

Base

• contains hydroxide (OH-) ions

• Taste bitter/chalky

• Slippery feel

• high pH

• conduct electricity in water

  • Turns red litmus paper blue

Hydronium

• water + proton (H+) → Ho3O+

• H3O+ is interchangeable with H+

Self Ionization of Water

• water is polar

• There are equal amount of hydrogen & oxygen

  • The reaction can be written as H2O + H2O <-→ H3O(aq) + OH-(aq)

Arrhenius Acid

• Produce hydrogen ions when they break apart in water

  • HCl-(aq) → H+(aq) +Cl- (aq)

Arrhenius Base

• produce (OH-) when they break apart in water

  • NaOH- (aq) → Na+ (aq) + OH- (aq)

Bronsted-Lowry acids

proton(H+) donors

Bronsted-Lowry bases

proton (H+) acceptors

conjugate bases

the species remaining after an acid has lost a proton

amphoteric

A substance that can act as an acid or a base… like water

Strong acids and bases form strong electrolytes (100% dissociation)

Nitric(HNO3), Sulfuric (H2SO4), hydrochloric (HCl), all group 1 hydroxides, Ba(OH)2

Weak acids and bases form weak electrolytes (partial dissociation)

Carbonic acid (H2CO3), acetic acid (HC2H3O2), ammonia (NH3)

acid pH

0-7

neutral pH

7

base pH

7-14

endpoint

When the indicator changes color & it should be close to the equivalence point

Acid base titration

The slow addition of one solution of a known concentration to a known volume of another solution of unknown concentration until the reaction reaches neutralization.

Acid base neutralization

All acid-base reactions are neutralization reactions, which produce an ionic compound(salt) and water.

“the stoichiometric point of titration”

The point at which moles of H+ ions from the acid=moles of OH- from the base.

percent yield formula

[actual yield (from an experiment)/theoretical yield] x 100

intermolecular force

As the intermolecular force gets stronger, more energy is required to break the forces holding molecules together. In other words, more energy is needed to melt solid or boil liquid.

vapor pressure

vapor collects above the liquid and exerts pressure on the surface of the liquid.

When does liquid boil

when vapor pressure equals atmospheric pressure

atmospheric pressure = 1 atm = 760 torr = 101.3 kPa

stronger the intermolecular force..

lower the vapor pressure at a given temperature

different intermolecular forces…

different vapor pressures

colligative properties

A property that depends on the number of solute particles and not upon the identity of the substance

• vapor-pressure lowering

• boiling Pt.Elevation

  • Freezing Pt. Depression

Chromatography

Separates chemical species by taking advantage of the differential strength of IMF’s between and among the components of the solution(the mobile phases) and with the surface components of the stationary phase.

The stationary phase

either a solid or a liquid supported by a solid

The mobile phase

the solvent

relative attraction

the relative attraction that each component of the solution has for the mobile phase (solvent) will allow you to separate each of the solutes in a mixture

oxidation reduction (redox)

redox reactions are characterized by a transfer of electrons

oxidation state

a way to keep track of electrons in oxidation-reduction reactions, particularly redox reactions involving covalent substances.

limiting reactants

the reactant is completely

Nonpolar Molecules

• no lone pairs

• same outside atoms

polar molecules

• lone pairs

• different outside atoms

london dispersion force

• nonpolar

hydrogen bond

• polar

• H is bonded to F, O or N

Dipole Dipole

• polar

• H not bonded to F, O or N

lol

saturated

a solution that contains the maximum amount of dissolved solute for a given amount of solute at a specific temperature and pressure.

unsaturated

a solution that contains less dissolved solute for a given temperature and pressure than a saturated solution (more solute can be dissolved.

supersaturated

a solution that contains more dissolved solute than a saturated solution at the same temperature.

conjugate base

formed by the removal of a proton from an acid

weak base

more H+ ions

lower pH

water dissolves what (polar,nonpolar, etc.)

water dissolves ions and polar molecules

mole ratio

higher concentration the concentration

higher boiling point