Polymer" is a generic term used to describe a very long molecule consisting of structural units and repeating units connected by covalent chemical bonds.
A key feature that distinguishes polymers from other molecules is the repetition of many identical, similar, or complementary molecular subunits in these chains.
These subunits, the monomers, are small molecules of low to moderate molecular weight, and are linked to each other during a chemical reaction called polymerization.
Polymer
Author: asim /
Chemical compound
Author: asim /
A chemical compound is a chemical substance consisting of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition.
The ratio of each element is usually expressed by chemical formula.
For example, water (H2O) is a compound consisting of two hydrogen atoms bonded to an oxygen atom. The atoms within a compound can be held together by a variety of interactions, ranging from covalent bonds to electrostatic forces in ionic bonds.
Real Gases
Author: asim /
Deviate at least slightly from Ideal Gas Law because of two factors:
gas molecules attract one another
gas molecules occupy a finite volume
Both of these factors are neglected in the Ideal Gas law. Both increase in importance when molecules are close together (high P, low T)
van der Walls equation corrects for the attraction between molecules.nb corrects for the volume of gas moleculesvan der Walls constants are given
gas molecules attract one another
gas molecules occupy a finite volume
Both of these factors are neglected in the Ideal Gas law. Both increase in importance when molecules are close together (high P, low T)
van der Walls equation corrects for the attraction between molecules.nb corrects for the volume of gas moleculesvan der Walls constants are given
Kinetic Theory of Gases
Author: asim /
Three postulates of the Kinetic Theory
1.Gases consist of particles (atoms or molecules) in continuous, random motion.
2.Collisions between gas particles are elastic.
3.The average energy of translational motion of a gas particle is directly proportional to temperature. In addition to the postulates above, it is assumed that the volumes of the particles are negligible as compared to container volume and attractive forces between particles are neglected.
Et = average kinetic energy of translationKEavgm = mass of the particleu = average velocity of the particle
from the third postulate we can formulateT = temperature in Kelvin, c = constant which has the same value for all gases.
A.Average Speed of Gas particles (find u)c = constant = R = gas constant, NA = Avogadro's #substituting for cmass times moles (NA) equals Molar Mass (MM), substituting MM and solving for u givesusing this last equation we can solve for an individual gas particle's speed rms = root mean square, which is the average square root of the speed of the individual particles.Use R = 8.3148 , in order for the units to come out in m/s
B.Grahm's Law
effusion - the flow of gas particles through a small opening or pinhole in a container.diffusion - random motion of gas particles.formulas:if the two gases are at the same temperature then:
Experimentally usually measure the time for effusion to occur, this time is an inverse of the effusion rate (lower times-faster effusion rates)
this equation was used for the separation of U238 during WWII by effusion principles.
1.Gases consist of particles (atoms or molecules) in continuous, random motion.
2.Collisions between gas particles are elastic.
3.The average energy of translational motion of a gas particle is directly proportional to temperature. In addition to the postulates above, it is assumed that the volumes of the particles are negligible as compared to container volume and attractive forces between particles are neglected.
Et = average kinetic energy of translationKEavgm = mass of the particleu = average velocity of the particle
from the third postulate we can formulateT = temperature in Kelvin, c = constant which has the same value for all gases.
A.Average Speed of Gas particles (find u)c = constant = R = gas constant, NA = Avogadro's #substituting for cmass times moles (NA) equals Molar Mass (MM), substituting MM and solving for u givesusing this last equation we can solve for an individual gas particle's speed rms = root mean square, which is the average square root of the speed of the individual particles.Use R = 8.3148 , in order for the units to come out in m/s
B.Grahm's Law
effusion - the flow of gas particles through a small opening or pinhole in a container.diffusion - random motion of gas particles.formulas:if the two gases are at the same temperature then:
Experimentally usually measure the time for effusion to occur, this time is an inverse of the effusion rate (lower times-faster effusion rates)
this equation was used for the separation of U238 during WWII by effusion principles.
The Ideal Gas Law
Author: asim /
Variables:
V=
volume (liters, cubic decimeters, milliliters, cubic centimeters).
n=
amount in moles, n = (MM = molar mass from Periodic Table).
T=
temperature, for gases must be in Kelvin, K = oC = 273.15, usually find temperature to nearest degree, so only add 273.
P=
pressure (atmospheres, millimeters of mercury, kilopascals, torr. 1 atm = 760 mm Hg = 101.3 kPa = 760 torr = 29.92 in Hg = 14.7 lb/in2, these are all at 0 oCtorr named after Torricelli - Italian scientist, first person to accurately measure atmospheric pressure, 1640
Calculation of Gas Pressure
barometer - closed manometer, take h directly.
manometer - open manometer.Pgas = Patm + P due to h mm Hg H2O is on the atmospheric side in the h part of the equation, this will effectively give the addition or subtraction from atmospheric pressure.
Relation between variables;
PV=nRTwhere R is a true constant, it is the same for all gases and is independent of P, V, n or T.
inputting standard temperature and pressure (STP) for any gas will give the same R, Avogadro's Law - the same number of particles at the same P, T, and V.
V=
volume (liters, cubic decimeters, milliliters, cubic centimeters).
n=
amount in moles, n = (MM = molar mass from Periodic Table).
T=
temperature, for gases must be in Kelvin, K = oC = 273.15, usually find temperature to nearest degree, so only add 273.
P=
pressure (atmospheres, millimeters of mercury, kilopascals, torr. 1 atm = 760 mm Hg = 101.3 kPa = 760 torr = 29.92 in Hg = 14.7 lb/in2, these are all at 0 oCtorr named after Torricelli - Italian scientist, first person to accurately measure atmospheric pressure, 1640
Calculation of Gas Pressure
barometer - closed manometer, take h directly.
manometer - open manometer.Pgas = Patm + P due to h mm Hg H2O is on the atmospheric side in the h part of the equation, this will effectively give the addition or subtraction from atmospheric pressure.
Relation between variables;
PV=nRTwhere R is a true constant, it is the same for all gases and is independent of P, V, n or T.
inputting standard temperature and pressure (STP) for any gas will give the same R, Avogadro's Law - the same number of particles at the same P, T, and V.
Matter and Measurements Review
Author: asim /AP ChemistryScience of chemistry dates form about 1800, chemistry is an experimental science.
1.Measured Quantities
Length
Volume
Mass
TemperatureKelvin: K= oC + 273.15Celsius: oC = K - 273.15
2.Significant Figures
significant digits: based upon the meaningful digits from the laboratory instrument, know the rules on page 13 of the textbook.
mathematics: multiplication and division addition and subtraction.
3.Conversion FactorsBased on the "bridge" between known and unknown
one step conversions
multiple step conversions
4.Types of Substances
elements: cannot be broken down into two or more simpler substances.Know symbols, location on periodic table.
compounds: contain two or more elements with fixed mass percents.sodium chloride NaCl 39.345 Na, 60.66% Cl
5.Properties of Substances:Used to identify a substance by comparing to the properties of known substances.
chemical properties
physical properties
density
solubility
specific heat: q = m ( T) (Cp)
color
6.Separation of Mixtures
distillation
chromatography
Chemical Formulas and Equations
Author: asim /I.Prediction of formulas of ionic compounds
1.Charges of monatomic ions of main group elements can be predicted from position in Periodic Table.
2.Transition metal cations can have multiple charges. You must know the common transition metals.(Table 2.4 page 62)
3.Polyatomic ions; know common ions, hand out.
Names of compounds
1.Ionic Compounds: give name of cation followed by that of anion (ends in -ide). If metal forms more than one cation, as with many transition metals, then names of ions have suffixes that are related to their ionic charges: -ous refers to the lower charge: -ic refers to the higher charge.
**The IUPAC (Stock Name) system uses Roman Numerals.**
2.Names of polyatomic ions containing oxygen- some elements form several polyatomic ions with oxygen. A series of suffixes and prefixes is used to specify the relative number of oxygen atoms.
per-........-ate
greatest number of oxygen atoms
........-ate
greater
........-ite
smaller
hypo-........-ite
smallest number of oxygen atomsThe mercurous ion is an exceptional case, it requires special attention. The formula and charge for the mercurous or mercury (I) ion is Hg2+2. Note that this ion contains two mercury atoms.
3.Binary molecular compounds (two nonmetals)Indicate number of atoms of each element using greek prefixes (page 67).
PCl3
N2O5
N2H4
Acid nomenclature
Acids- Acids are molecular compounds that contain hydrogen bonded to a nonmetal to a group of atoms that behave like a nonmetal. Acids can be either binary or ternary compounds. The names of binary acids have the form Hydro-........-ic acids. The names of ternary acids use a series of prefixes and suffixes to specify the relative number of oxygen atoms in the molecule.
per-........-ic
greatest number of oxygen atoms
........-ic
greater
........-ous
smaller
hypo-........-ous
smallest number of oxygen atoms
If only two different ternary acids exist for a given nonmetal, only the suffixes -ic and -ous are used.
HClO4
perchloric acid
HClO3
chloric acid
HClO2
chlorous acid
HClO
hypochlorous acid
Significant Digit Rules
Author: asim /1.The number of significant digits recorded for a measurement includes all of those digits known with certainty plus the first digit about which there is some uncertainty. The first digit in which there is some uncertainty is the first digit which is estimated
2.The only time significant digits must be considered is when dealing with measured quantities. You will only deal with two types of numbers, those which are part of a measured quantity and pure numbers. An example of a pure number is the number 2 when it indicates the diameter of a circle is twice the radius of a circle. Another pure number would be the number 5 when you say five people. Many conversion facts are also pure numbers like 5280 ft = 1 mi or 1 in = 2.54 cm. Pure numbers have infinite number of significant digits. The fact that pure numbers have an infinite number of significant digits means they will never be the number which limits the numbers of significant digits in the result of a calculation using measured quantities.
3.All digits which are not zeros are significant digits.
4.Any zeros between nonzero digits are significant
5.Any zeros which simply hold the decimal point in position are not significant digits. A simple test for this kind of zero is to write the quantity in scientific notation. If the zeros disappear they are not significant. A further description of these kinds of zeros would be either -
1"ending" zeros (for big numbers) which are to the right of any nonzero digit but to the left of the decimal point, or
2"leading" zeros (for small, decimal numbers) which are to the right of a decimal point but to the left of any nonzero digit.
6.In a number such as 56,500 a special effort must be made to indicate the place value to which the quantity was recorded in the event the zeros are significant. A line above a zero or below it indicates that the zero is significant and it is the first estimated digit or the last significant digit.
7."Trailing" zeros (for decimals) which are to the right of the decimal point and to the right of any nonzero digit are significant because they indicate the measurement has been carried to that degree of precision.
8.When adding or subtracting measurements you should first calculate the answer using all digits available. Then you should determine to which place value you should round your answer. To do this determine the estimated digit in each number used in the calculation (this would be the last significant digit in each number). Then, as you proceed from left to right, the first column in which you find an estimated digit should be the column or place value to which you should round off your answer.
9.In multiplication or division of measured quantities you should first perform all of the calculations involved. Then determine how many significant digits are in each of the quantities used in the calculations. Round off your answer so it has only as many significant digits as the quantity which contains the least number of significant digits.
10.When taking a logarithm the number of digits to the right of the decimal is equal to the number of significant digits in the number that you are taking the logarithm of.
AP Chemistry: Basic Knowledge
Author: asim /Elements
Symbol
+Oxidation
-Oxidation
aluminum
Al
3+
barium
Ba
2+
beryllium
Be
2+
boron
B
3+
bromine
Br
-1
cadmium
Cd
calcium
Ca
2+
carbon
C
4+
-4
cesium
Cs
1+
chlorine
Cl
-1
chromium
Cr
3+
cobalt
Co
2+, 3+
copper
Cu
1+, 2+
fluorine
F
-1
gold
Au
1+
helium
He
hydrogen
H
1+
iodine
I
-1
iron
Fe
2+, 3+
lead
Pb
2+, 4+
lithium
Li
1+
magnesium
Mg
2+
manganese
Mn
mercury
Hg
neon
Ne
nickel
Ni
nitrogen
N
-3
oxygen
O
-2
phosphorus
P
-3
platiunm
Pt
potassium
K
1+
silicon
Si
silver
Ag
1+
sodium
Na
1+
strontium
Sr
2+
sulfur
S
-2
tin
Sn
2+
zinc
Zn
2+
POLYATOMIC IONS
phosphate
PO43-
ammonium
NH41+
acetate
CH3COO1-
hydroxide
OH1-
nitrate
NO31-
carbonate
CO32-
sulfate
SO42-
chlorate
ClO31-
chromate
CrO42-
dichromate
Cr2O72-
peroxide
O22-
cyanide
CN1-
permanganate
MnO41-
oxalate
C2O42-
hydrogen phosphate
HPO42-
dihydrogen phosphate
H2PO41-
thiocyanate
SCN1-
thiosulfate
S2O32-
hydrogen carbonate
HCO31-
mercury (I)
Hg22+
ACIDS
oxy-acids
acetic
CH3COOH
carbonic
H2CO3
nitric
HNO3
nitrous
HNO2
phosphoric
H3PO4
sulfuric
H2SO4
sulfurous
H2SO3
non-oxyacids
hydrochloric
HCl
hydrofluoric
HF
hydrobromic
HBr
hydroiodic
HI
hydrosulfuric
H2S
hydrocyanic
HCN
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