Gen Chem 1 Final

Matter

Most basic building block. Must have mass and volume

Elements

Simplest form of matter, can't decompose any further

Molecules

Two or more atoms "linked" together

Compounds

Mixes of two or more elements bonded together

Sig Fig.- x & /

As many as the least number

Sig Fig.- + & -

As many as the least behind the decimal point

Law of Definite Composition

Components in a compound always have the same ratio by mass

Law of Multiple Proportions

Ratios of elements that combine to make a compound are always in fixed, whole number, proportions

Atom Distinguishing

The only thing that distinguishes one atom from another is the number of protons

Isotopes

Sam element, different number of neutrons

Cation

Carry the positive charge, a metal

Anion

Carry the negative charge, non-metal

Diotonics

O₂, H₂, N₂, F₂, Cl₂, .....

Covalent Naming

Name both compounds with number prefix

mono, di, tri, tetra, penta

CO₂ Carbon dioxide

Ionic Naming

Metal (Cation) + Non-metal (Anion)

KBr- Potassium Bromide

Molecular Weight

Sum of all the atomic masses of elements in molecule

Avogadros Number

6.022 x 10²³ "things"

Percent Composition

Molecular weight- mass of compound- x100= percent

Empirical Formula

Simplest ratio of elements in compound

Molecular Formula

Actual number of moles of elements in compound

P₂O₅ vs. P₄O₁₀

Law of Conservation of Mass

# Reactants = # Products

Limiting Reagents

One element limits the reaction because you will run of that sooner, leaving some of the other compound left over

Aqueous Solutions

Water solution in which a substance is dissolved

Homogeneous solution

Two things mixed together to make one, where ever you take a sample, the composition will be the same

Solvent

The major component (aqueous is water)

Solute

The minor component ( usually a salt or an acid)

Forming ions

Ionic compounds that DO dissolve in water, form ions, or electrolytes

Electrolytes

ion in water, can't begin until the compound dissolves in water.

Number of ions formed

When looking at salts, the number of ions formed tells how good at conduction electricity it is

Strong electrolyte

a compound that dissolves 100% and generates ions

Strong acid

HCl, HNO₃, HBr, HI, H₂SO₄

Strong bases

OH⁻ NaOH, LiOH, KOH

Weak electrolytes

Mostly weak acids, compounds that don't dissolve completely in water

Non- electrolyte

compounds that dissolve in water but don't form ions (glucose)

Molecular equation

Total equation, balanced with no charges

Complete Ionic equation

Every compound dissolved in solution broken into ions, charges everywhere!

Net ionic equation

Only the compound that is coming out of solution are shown as ions and then as compound

Spectator Ions

Ions that don't come out of solution in a given reaction, are just there to balance charges

Acid- Base Neutralization

HCl + NaOH → H₂O + NaCl

Acid

Any compound when ionized yields H⁺

Base

Any compound when ionized yields OH⁻ or will accept H⁺

Oxidation Reduction Reaction (redox)

S₈ + O₂ → SO₂

Oxidation

Atom or ion loses electron. Positive change

Reduction

Atom or ion gains an electron. More negative change

Molarity

Molarity= Concentration= (Moles of solute/ total volume)

Units: Moles/ Liters

Dilutions

M₁V₁= M₂V₂

Titration

Stoichiometry= Liters- moles- molar ratio- grams

Equivalence point

Added exactly enough base to neutralize acid or vise versa

Thermochemistry

Relationship between chemical reactions and energy changes associated with them

Energy

The capacity to do work, the ability to provide heat

E= W + q

Kinetic energy

energy of motion

KE= 0.5mv²

Potential energy

stored energy, energy that hasn't been released yet

PE = mgh

First Law of Thermodynamics

You can't make or destroy matter, only change its form

system

area you're studying (beaker)

surroundings

area around experiment (air inside classroom)

Total energy of reaction

E of universe= E system + E surroundings

Activation energy

Energy needed to 'get over hump.' Reaction needs energy input

Exothermic

Heat from system is lost and gained by surroundings, feels hot

Endothermic

Heat from system is absorbed and lost from surroundings, feels cold

1 calorie =? J

1 calorie = 4.184 J

U

All the energies= electron movements, atom movements, bond vibrations, ect.

Delta U= ?

Delta U= q + W

* most chemical rxns have no W, so usually U=q

Chemical rxns with Work

W= -PV (piston example)

Calorimetry

Heat capacity= energy required to raise the temp. of an object 1 degree K

Heat capacity

q/T

Specific heat

C= q/ Tm

Coffee cup calorimetry

Pressure remains constant. Any change during rxn can be directly reflected in a temp. change

Heat transfer

-q lost= q gained

Bomb calorimetry

No volume change, so there is a pressure change.

-q lost = q gained

*remember that q gained is water on outside as well as the whole apparatus

State functions

function (such as energy) whose value is determined by that function's present condition

*As long as your beginning and ending conditions are the same, U= 0

H

= enthalpy, state function and extensive property ( dependent on amount of material)

Delta H=?

Delta H= Delta U + P Delta V

-Delta H

Exothermic

+Delta H

Endothermic

Special notes on H

Remember: Stoichemtry, opposite rxn has opposite sign, P and T must be stated

Hess' Law

the enthalpy change for an overall process, is the enthalpy changes for its individual steps

-specific heat₁m₁T₁=

specific heat₂m₂T₂

Standard heats of formation

heats of formation, enthalpies associated with forming a compound from its elements

Hrxn

sum of all Hf (products) - sum of all Hf (reactants)

Light

Frequency determines type of light.

visible light, microwaves, radio waves, ect.

peak to peak is the wavelength

how many waves per length of time is frequency

per second

per second, s⁻¹, Hz (Hertz)

Inverse relationship between frequency and wavelength

Longer the wavelength, lower the frequency

Shorter the wavelength, higher the frequency

C=?

C= Yv

C= constant (speed of light)

Y= wavelength

v= frequency

Speed of light

3.0 x 10⁸ m/s

Emission spectrum

spectrum obtained when radiation is emitted by an element that was energized by some for of energy, usually voltage.

Hydrogen spectrum

monochromatic radiation, not a continuous spectrum (rainbow). There are discrete wavelengths that light are emitted, these wavelengths are specific to elements

Bohr atom

Electrons in an atom have specific energy levels it's allowed, electrons can move from one energy level to another, but can't move to an intermediate space

Visible light equation

Delta E= hv

E- Energy

h- planks constant ( 6.63x 10⁻³⁴ Js)

v- frequency

Photon

A set amount of energy, the energy between two energy levels

Quantized example

Like stairs, overshoot, land on stair you intended to land on, undershoot, and fall back down to the one you were standing on

Delta E=?

Delta E= hc/Y

Delta E- Energy

h- planks

c-speed of light

Y-wavelength

Photoelectric effect

Shooting a sheet of metal with such a high voltage that the electrons on the metal get so excited that they pop off the metal

Threshold of energy

photon (energy packet) that is required to pop electrons off. Specific to each element

Light can have matter properties

then matter can have wave light properties

Dual Wave Particle Theory

de Broglie model: electrons orbit nucleus in a wave then in a circle (Bohr)

E=

E=mc²

(speed of light) m=

m=h/Yc

m=mass

h=planks constant

Y=wavelength

c= speed of light

(velocity) m=

m=h/Yv

v=velocity

If something has mass and is moving, then there is a Y associated with it...

Y=h/mv

Heisenberg's uncertainty principle

You can't know the position, or location, AND the momentum of an election in an atom at the same instant