Chemistry Semester Exam

What is the history of the word alchemy?
Philosopher’s Stone
Where did alchemy start?
India ; China
Alchemy is of what use to science?
Transforming common chemicals into gold creating the phillosphers stone
Who was consider the first legit Chemist and Why?
Robert Boyle; using experiment to measure relationship between pressure and volume of gas
Who was the “father of modern chemistry” and why?
Antoine Lavosien discovered that  matter may change it’s shape or form
What do Chemist do?
apply information about matter and the changes it undergoes to improve our lives in different ways.
Top Chemicals in the U.S.A.
Sulfuric Acid, Nitrogen Ethyene, Oxygen, Propylene, Chlorine, Ethyene Dichloride, Phosphric Acid, Ammonia, Sodium Hydroxide
Which greek Phillosphers were know as the “thinkers”; their experiments were based on logical thinking with no basis in experiment
Socrates, Plsato, Aristotle
Generic  Step of the Scientfic method

1. find a Problem/ Research

2. Make a Hypothesis & test

3. Interpet Results

4.State Conclusion in a public form

Serendipity
chance and unexpected findings base on good observations have often moved science in unexpected and rewarding ways
Hypothesis
is an educated guess. it is normally formed in an “if-then” statement
Varaibles
Factors that effect the outcome of an experiment.
Chenistry common varriables are . . .
P, T,n,V
Theory
explanation for some phenomeon that is base on verified observation repeated experimentation and reasoning.
Scientfic law
represents descriptive facts of nature that are indisputed
Experiment
is a method of testing a hypothesis
Controlled Experiment
compares the result to a control sample, identical to the test sample- expect for one variable being tested.
Models
are simulations, subittiutes or stand ins for a process or obeject we are unable to directly observe
In Science we measure data ________.
Quantitatively
Qualitative observations are __________.
Non-Numerical
Kilo

K

1000

Deci

d

.1

Centi

c

.01

Milli

m

.001

Matter
anything having mass and volume
volume
space an object occupies
Volume =
L X W X H
Mass
quanity of matter contained in an object
Weight
A Measure of gravity on a given mass
Temperature
represent the average kentic energy of particles in a sample of matter.
Heat
is a movemnt of thermal energy of the particles in a sample of matter.

 

atoms

building blocks of matter
Pure Substances
can contain either a single element or a single compound …. they only have one type of atom
Element
pure substance with one type of atom
Compound
is a pure substance containing two or more atoms in a different reaction
7 diatomics
H2, N2, O2, F2, Cl2, Br2, I2
Mixtures
contain two or more pure substances that are not chemically combined.
Gold  Alloys
24 Karat is the maxium gold content (100% gold)
Mixures are classified as ______ or _________
Homogeous; Heterogeous
Homogenous Mixtures
same throughout
Heterogenous Mixture
part with different properties
Allotropes
mutiple forms of molecules of the same element
Solids
Constant volume and constant shape
Liquid
Constant volume and Variable shape
Gases
varaible volume and Shape
Macroscropic Properties
are observations with the naken eye – atoms in bulk show these properties
Microscropic Properties
show particles in layered form- too small to see with the naked eye must be observed indirectly.
Physical Properties
can be observed without changing the idenity of subsances changes of state.
Chemical Properties
Can only be obsevred when a substance is changed into a new substance
Chemical Reaction
Process by which one or more substances change into one or more new substances with new properties
Energy
ability to do work
Energy forms are either _____ or ________
Potential; Kinetic
Potential Energy
comes in forms that are stored including chemical, graduation, mechincal and nuclear
Kinetic Energy
forms are doing work involving movement or somekind – like electrical, heat, light, motion, and sound.
Endothermic
process invloving an absorption
Exothermic
Process involving a relase of energy
Law of Conservsation of Energy
durring any physical or chemical change energy is not created or destroyed
The total amount of energy and matter in the universe is constant( does not change).
System
is the container and reaction under study
Surroundings
everything outside the system
Heat is energy transfered . . .
between objects atdifferent temperatures.
Energy always . . .
moves from the hot object to the cooler object.
Conduction
direct contact
Convention
little indirect contact
Radiation
little absorption
Temperature
is a measure of the Average kinetic energy of the particles in a sample of matter
Kelvin =
K= C+ 273.15

Celius =
C= K- 273.15
Work
is forced applied over a distance
Work =
W= Force(Distance)
The Greeks Thought were four types of Atoms ____, ____, ____, _____.
earth, air, water, fire
Thompson viewws the atom as a ____ ____ containing an equal mix of changes in a _____ sphere. This is sometimes called the ____ pudding model.
solid sphere; charges; positive; plum
Daltons Theory: 5 Major Principles

  1. all matter is made of indivisible and indestructive particles.
  2. like atoms have the same physical/chemical properties.
  3. different atoms have different phyiscal/chemical properties.
  4.  atoms combine in a wide-number of ratios to make compounds.
  5. atoms cannot be detrosted or created in chemical reactions.

Cathode
Negitive Electrode
Anode
Positive Electrode
Law of Comipition
Compounds have the same element in the same properties by mass no matter what the source.
Law of Conservation of Mass
Durring the chemical reaction the mass of the product equals the mass of the reactants.
Law of Mutiple Proportions
when two elements so make differrent compounds they combine in simple whole number ratios
Nucleus

is the centeral region of the atom. Very Desnsed,

 Positive Charged

Protons
Heavy and charged particles found in the nucleus. Nutral
Nuetron
negitivly charged particle, found in nucleus
Electron

negitive charged small particles orbiting at relatively large distance from the Nucleus. Aka Beta Particles.

Alpha Particles

positive two charged particles emitted from the nucleus of large unstable atoms. it has two protons and two neutrons. 

The ____ _____ _______ acts like an atomic velcro ______ the same charged particles from ______ on another.
Strong Nucleus force; kepping; rerepelling
Atomic Number
is the number of protons in an atom.
Mass Number
the sum of the number of protons and neutrons in an atom’s nucleus.
Isotopes
are elements with the same number of protons but different number of neutrons
Atomic Mass
is the average mass of all the isotopes of an element
It is the element _____ that determines the chemical properties of an atom
arrangement
______ do not orbit the nucleus in nice circular orbits.
Electrons
______ can be describe as particles and waves.
Electrons
a _____ is a region around a nucleus where electrons are likely to be found.
Orbital
a ____ _____ electron is in its lowest energy state.
Ground State
Exicited state electrons =
e-
exicited electron is _____ and re-emits Energy as it ______ to the ground state.
unstable;relaxes
The Entire spectrum contains . . .
Gamma Rays,X-Rays, UV, Visible, IR, Microwaves, Radiowaves
Frequency
number of waves/second
Wavelength
distance between peeks on adjacent waves
high frequency waves have _____ wavelength
short
Principle Quantum Number
indicates the main energy level
Angular Momentum
the main energy levels are divied into sublevels of that electron
S orbitial =
2 electrons
P orbital =
6 electrons
D orbital =
10 electrons
F orbital =
14 electrond
1s
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f
6s 6p 6d
7s 7p
8s
half-life
the time required for half of the atoms in sny given quanity of a radioactive isotope to decay is the half life of that isotope. each particular isotope jad its own unique half-life.
i have 300 donuts. how many dozen is this?
300 1dozen
_____________ = 25 Donuts
12 dounts
The Standard isotope for measuring mass is the ______ isotope
C-12
one Mole =
6.022 X 10^ 23
mole is also know as
Avogadro’s number
bubba has 1.256 X 10^24 atoms of Zn.
1.256 X 10^24 1 mol
____________________________ = 2.08 mol
6.022 X 10^24
When elements are arranged by the ___ ___, several trends are apparent. Trends are ______ in the physical and chemical properties id the elements. these trnds become apparents in the ______ and the ______ of the table.
atomic number; patterns; families; series
Atomic radius
half the distance between the center of two like atoms. atomic radius increases down a family
atomic radius _____ across
decreases
Atomic Radius Trends:
the ____ gas configuration is a _______ condition for an atom. _____ atoms tend to ____ or ____ electrons to obtain a Noble Gas Electron Configuration.
Noble;stable;Neutal; lose, gain
Ions
An atom or a group of atoms that has gained or lost electrons and become positivly or negitively charged
Ionic radius Graphical Trend:
They _____ down a family ionic size _____ generally. Across a peroid, ionic size radius _____ grenerally.
move; increase; decreases
Ionization Energy
Energy required to remove an electron from an atom or ion. as you go down a family the ionization decrases. As you move across a peroid the ionization of energy increases.
Electonegitivly
This measures the attraction an atom has for electrons while its bonding with another atom. down a family this decrease across a peroid this increases.
Shielding effect
as an atom gets larger with the addition of extra energy levels, the affect increases. this is because they are “shielded” from a strong attraction by the nucleus due to the extra layers of the outer electrons and the nueclus. shielding effect increases down a family. it remains contstant within a peroid.
Most ____ Seek lost their Electrons
Metals
_______ tend to seek to gain electrons
nonmetals
8 electrons is a . . .
Octlet
most reactive elements are the . . .
Alkalimetals and the halogens
Metals ____electrons
lose
nonmetals ____electrons
gain
ions have unique properties unrelated to the properties if the element
“Octet Rule”
Cations
+
Anions
salt is a _____ compound formed by negitivly and positive charged ions
ionic
There are _____ types of salts
thousands
Most _____ & _____ are ionic compounds
rocks minerals
ionic compounds are _____ ______ ______ as molecules
not the same
Acetate
C2H3O2-1
Chlorate
ClO3-1
HYDROXIDE
OH-1
NITRATE
NO3-1
NITRITE
NO2-1
SULFATE
SO4-2
SULFITE
SO3-2
CARBONATE
CO3-2
PHOSPHATE
PO4-3
AMMONIUM
NH4+1
Covelant bonds
these form between nonmetals
Attractive forces are ____ ____ ____ particles
between oppsite charged
Repulsive forces are ____ ____ ____ particles
between like charged
Molecular Compounds
compounds formed from covalent bonds
0.0 to 0.5
nonpolar covalent
0.6 to 2.1
polar covalent
2.2 to 3.3
ionic

mono =

di=

tri=

tetra=

penta=

hexa=

hepta=

octa=

nona=

deca=

mono =1

di=2

tri= 3

tetra=4

penta=5

hexa= 6

hepta= 7

octa=8

nona=9

deca= 10

 covalent compounds are correctly called _______, while ionic are correctly called “_______ ______”

Molecules; ” Formula Units”

The atomic mass of their compound is the ____ of all the atomic masses in the compound

SUM
The Percentage composition Calculation allows is to calculate the ______ of ________ for each element in a compound.
Percentage of mass

Percentage composition of Magensium hydroxide

 

MgOH2

24.3/58.3 X 100 =41.6%

32/58.3 X 100= 54.8%

2/58.3 X 100= 3.43%

Remeber to add the mass of Water !!!!!! 🙂
Emprical Formual
is the mathematically reduce formula of a chemical formual.
In emprical formula percentage convert to _____
grams
find the emprical formual for the compouind containing 46.7% Si and 53.3% O2.

46.7g Si    1mole


                 28.086g

= 1.66

 


 

Properties of Solids

  • particles close together
  • ordely fixed arrangement
  • particles wobble into place
  • ionic solids are unsually crysaliione material
  • covalent solids varry from damonds to waxes to greases
  • density relavitly high
  • hardness depends on substance  

Properties of Liquids

  • have a random arragment of particles
  • held by attractive forces
  • similar density to solid
  • slide past each other
  • viscostiy= restanice flow
  • coplairy action
  • attractive to glass surface
  • surfacetension 

 

Example of Liquds

propane

melted solid

gasoline

oil

alochol

milk

juice

vingear

ammoniuia

anti-freeze

Properties of gases

  • particles are relvatively far apart 
  • they dont have much attraction towards each other
  • fill any conatainer placed in
  • varraible shape and volume   

Freezing/Melting
Liquid <-> Solid
evaporation/bolling/condensation
Liquid <-> gas
Sublimation / depsoition
solid <-> gas
Most substances can contain in all three states of matter
Intermolecular forces
attractions between oppositively charged ions
Dipole-Dipole
polar molecules are those that do not share thier electrons well. As a result they have “partial” charges which allow them to attract to their neighbors.
Solution
homogenous mixture of substance
Suspension
mixture where particles settle out
heterogenous
different throughout
homogenous
same throughout
Solvent
greater amount
Solute
less amount
alloy
mixture of two or more elements
alloy
mixture of two or more elements
colliod
mixture where the particles reflect light
Decant
fdraw off a liquid sediment
Tyndall Effect
scattering of light by particles
Filteration
seperation of solids from fluids
Chromatograpghy
seperation of mixtures
Distillation
Evaporation and subsequent collection of a liquid by condensation as a means of purification.
Solubility
max amount of a substance that will disslove at a specfic Temperature.
Polar
Not symmetric
x

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