chemistry final

fundamental building blocks of life are called (t1)

atoms

dalton’s model

• all elements = invisible/indestructible

• basic unit of mater =atom

• Compounds are formed from combinations of atoms.

• use solid sphere cannon model

JJ Thomson model

• used the cathode ray to show one of the smaller units that make up an atom.

  • Cathode ray: beam particles deflected by electric/magnetic fields, particles= neg charge

  • Plum Pudding: atoms = sphere of (+) charge, electrons = (-) scattered like raisin in pudding

rutherfords

• Directed alpha particles (+) @ gold foil

• Passed through atoms = empty space, electrons orbit nucleus

• Deflected bk = small dense (+) center nucleus b/c protons

• gold foil experiment

Bohrs

Planetary model: electrons move circular orbits (energy lvl) around nucleus (1st lvl = less energy, 2nd lvl = more energy)

wave mechanical (modern day)

• Electrons = particles/waves

• Position of electron = ?

• Electron space = orbitals, energy lvls, sub lvls

subatomic parts

Name	Charge	Mass	Location	Calculate Mass
Proton	Postivite +	1 amu	Inside the nucleus	Always equal to the atomic number
Electrons	Negative -	n/a	Orbital	If neutral then # = # of protons
Neutrons	Neutral charge	1 amu	In nucleus	MAN =  mass- atomic number = neutrons Atoms must be electrically neutral

positive charge

electrons lost

negative charge

electrons gained

Calculating atomic mass-

Abundance will be a percent 

C-12     97%

C-14     2.7%

C-15     .3%

(must make it into a decimal- move two times to the left)

Mass x % = 

C-12     .97

C-14     .027

C-15     .003

Add all 3 answers up to get the atomic mass

• It must be between the lowest and highest (between 12 and 15

Ground state

• lowest energy lvl

• look at the periodic table

• ground to excited = absorbing energy

excited state

• same # of electrons as ground state b/c the electrons dont change

• excited to ground = releasing energy

• EX- Magnesium = 2-8-2 (if it goes into the excited state the electron will jump) 2-7-3

bright line sepectrum

• comes from excited —> ground b/c it releases energy in the form of light

• make sure the lines match up

mater

broken up into pure substances and mixtures

pure substances

• all elements

• compounds

  • made of 2+ atoms, combined chemically, fixed ratio (not changing),

• must be homogenous ex h2o

homogenous

same, uniform, singluar appearance

• can be both pure susbstances + mixtures

mixtures

• 2+ pure substances combined physically

• composition varies

• both homo and heter

  • homo: salt water, air

  • hetero: oil and water (seperates)

heterogenuous

diff parts, varies, between samples, ONLY mixtures

pure substances (elements and compounds) + mixtures diagrams

Diatomics

H O N F Ci Br I

HONFCi = Gas

Br = liquid

I = solid

nitrogen ex of diatomic

filtration

 will separate an undissolved solid from a liquid (based on size)

• use to sep sand from water

evaporation

 will separate an undissolved solid from a liquid (based on diff boling points)

• use to sep salt from salt war

distillation

how dissolved liquids sep/ sep 2 miscible(mixable) liquids

• happens b/c diff boiling points

chromotography

sep colors and pigments (based on diff forces (strength of attraction)

speratory funnel

sep 2 immiscible (not mix)

• like oil and water

souable

does it dissolve

Nuclear chem Nucleus (t12)

• (+) protons + (n/a) neutrons = nucleus is always (+)

• dense b/c protons = 1amu + neutrons = 1amu

• small center of atom

• nuclear chage = # protons = atomic #

carbon 14

nuclear chemistry dating

uranium 238

rock dating

Iodine 131 (radioactive)

help treat thyroid

colbat 60

treat cancers

isotopes

atoms of the same elements w/ diff mass # b/c diff # of neutrons

• same # of protons always

ions

has charge b/c of the gain or loss of electrons

meltdown

when nucleus gets unstable

radioisotopes occur

unstable b/c proton:neutron ratio, moving it out of the belt of stability

• Too many neutrons → unstable

• Too few neutrons / too many protons → unstable

• Stable atoms are inside the belt of stability

radioisotope 2 decay products

1. unstable nucleus —> stable

• an atom with an unstable nucleus that decays and releases radiation to become more stable.

2. emission: table 0, radioactive, # on top = mass, # on bottom = charge

flow chart for understanding

Unstable nucleus → radioactive decay → alpha/beta/gamma radiation → more stable nucleus

Example:
Carbon-14 → Nitrogen-14 + beta particle

gamma radition

has the best penetrating pwr bc no weight/charge

natural transmutations

• Alpha decay: atomic number goes down 2

• Beta decay (β⁻): atomic number goes up 1

• Positron emission (β⁺): atomic number goes down 1

artifical transmutations

fission: reaction split heavy nuclei, highly radioactive

fusion: combine light nuclei

• lots of fission and fusion on the sun

e=mc²

• small amts of mass release large amts of energy

• nucleus > chemical reaction

half life ( table N)

• amt of time it takes for exactly ½ of a radioisotop to decay

• never reach 0, can’t get rid of it

• shoter ½ life = less stable isotope

• express life of a isotope

  • Start with 100 g of a radioisotope.

    After 1 half-life → 50 g left
    After 2 half-lives → 25 g left
    After 3 half-lives → 12.5 g left

how to calculate half life/chart

total time passed ÷ half-life length = # of half-lives

EX

Half-life = 6 days
Time window = 24 days

24 ÷ 6 = 4 half-lives

Then cut the sample in half 4 times:

100 g → 50 g → 25 g → 12.5 g → 6.25 g

So after 24 days, 6.25 g remains.

Matter Solids(T4)

• shape = definite doesn’t change

• volume = definite

• hardly move, vibrating

• must be touching the bottom in the diagram

liquid

• shape: takes container, not definite

• volume: definite

• particles roll like fluid, not as closely

• must be touching the bottom in the diagram

gas

• shape: not definite

• volume: not definite

• fills its container, spread out

kinetic energy

• movement of particles

• temp is the measure of avg kinetic energy

potential energy

• stored energy b/c of its position

heating curve

• melting point = 0, heating point = 100

• upward slope = increase of kinetic energy

• constant slope = no change in kinetic energy, increase of potential, equalibrium phase,

sublimation

solid —> gas

cooling curve

• downward slope = decrease of kinetic energy

• constant slope = no change in kinetic, decrease of potential, equilibrium

desposition

gas —> solid

exothermic

releases/exits heat/energy

• ex: freezing condensation, combustion

endothermic

absorbs heat/energy

• melting, evaporation, boiling

kelvin

on table t

MUST conver to kelvin when comparing with a celcius temp

Table T

Know how to do heat equations,

• MUST CONVERT TO CORRECT LABEL

  • ex: 3275J = 3.275KJ

Kinetic Molecular Theory

behaviors of an ideal gas

• constant random straight line motion, high energy

  • why gas particles don’t attract because of that motion

• collision are perfectly elastic: energy never gets lost, but can transfer

• gas particles sep by great distances, allowing it to occupy the space fully

how to control gas/make gas to ideal

• low pressure: gas particles are far apart, so they barely attract each other

• high temps = particles move fast so attraction matter less

• indireact relationship

relationship with temp and volume

• direct

• increase of temp is also increase of volume (vice versa for decrease

relationship of temp and pressure

• direct

• increase of temp is also increase of preassure (vice versa for decrease

preasure

atm/kPA

know how to use table gas laws (given)

Formulas/Equations Diatomic are (T2)

2 identical molecules

quantitative

a #

• ex: 2 hydrogens

qualitative

cannot be measured
ex: compound

molecular formula

the exact #
ex: C2H2

empirical formula

smallest whole number ratio
ex: C2H2 —> CH

gained electron

F-

lose electron

Na+

Coefficent

number of moles, infront of the compound

hydrates

ionic(salts) compounds containing water

ex: CuSO4 —> CuSO4 × 5H2O

Protons = Electrons

atom is neutral

Electron # change

it is an ion

Densitiy

doesnt change @ table S, no mater how small or big it is

physical change

no composition change b/c no chemical change

chemical change

need chemical reaction —> new product

• 2 sides: reactants —> products

if heat is on the reactant side

endothermic

if heat is on the product side

exothermic

Type of reactants: Synthesis

A+B —> AB

Decomposition

AB —> A+B

Single replacement

A+BC —> AB +C

Double replacement

AB +CD —> AD +CB
Positive Ions always goes first

three things conserved

mass, energy, and charge

know how to balance equations

Gram formula Mass (molecular mass) t3

1. inventory = how many

2. count atoms (subscript)

3. look up mass, periodic table and round to the nearest whole number

4. multiply

5. add

ex: H2O

H: 2×1 = 2

O = 1 ×16 = 16

18 mass of H2o

avogadro number

6.02 × 10²3 = 1 ole

to find # moles

give mass/GFM (table t)
- know how to do mole:mole ratios, percent composititon, etc

periodic table t5

arranged by increase of atomic number

• elements in the same group have similar chemical properties

group 1

• alkali metals, hydrogen is exceptions

• extremely active

• Fr is most active #87

• 1 valence electron

group 2

• alkali earth metals

• 2 valance electrons

Group 3-12

• transition metals

• formed colored ions in solution

• multiple oxidation states

group 13-16

• B, Si, As, Ge, Te, Sb

• metalloids

• semi metals depends on what its combined with

group 17

• halogens

• most active non metals

• flourine = most active non metal (g)

• F and Ci = G

• Br = liquid

• I = solid

• semi metals b/c they gain/lose to reach octect

Group 18

• noble gas

• inert, dormit, sleep

• 8 valanced electrons

• octect

elements in the same pd

similar energy levels

Metals

• solids at room temp (mercury is the exceptions)

• maulable (changing shape), ductile (pull into a wire) , luster (shiny)

• good conducter b/c mobile valence elctrons

• low electric negativity/ionization

• lose elctrons to form (+) ions

• radius = smaller

Bromine

• only liquid non metal

• brittle and not mauable/ductile

• poor conductors of heat/electricity

• form (-) ion

Allotropes

diff forms of the same element that have diff structures, diff physical/chemical properties

• exL Carbon- Diamond, graphite, fullerenes

• Oxygen: O2 and O3 ozone

Octect

easier to loose, to achieve octet
- atoms want 8 valence electrons b/c stability for atom

ionzation

energy required to remove one valence electron from an atom.

-High ionization energy = hard to remove/steal electron
Low ionization energy = easy to remove/steal electron

electron affinity

attraction for electrons