SDSU Chemistry Placement Test

proton

-heavy

-positively charged

-nucleon

neutron

-heavy

-neutral

-nucleon

electron

-very small (1/1800 of proton)

-negative

-outside of nucleus

properties of nucleus

-# of protons determines the element

-held together by nuclear force

-# of protons is extremely stable unlike # of electrons

atomic number

equal to the # of protons

atomic mass

# of protons + # of neutrons averaged across all of the element on earth

isotopes

-when elements have different masses but the same chemical properties

-ex. silver-107 and silver-109

lewis dot

-a 2-D model that represents covalent bonds as straight lines, ionic bonds as spaces, and unbonded valence electrons as dots

-can have single, double, or triple bonds

physical properties of compounds and molecules

-melting point

-boiling point

-solubility

-electrical conductivity

molecular mass

# of atoms(atomic mass)=molecular mass

type (n)one of naming inorganic compounds

-metal and nonmetal

-cation anion-ide

-ex. NaCl: Sodium Chloride

type(II) of naming inorganic compounds

-cation( ) anion-ide

-ex. CuO: Copper(II) Oxide

type tri of naming inorganic compounds

-cation prefix anion-ide

-ex. CO: Carbon Monoxide

balancing equations

-need an equal number of atoms on each side

-ex. C12H22O11 + O2 --> CO2 + H2O

C12H22O11 + 12O2 --> 12CO2 + 11H2O

stoichiometry

-measuring the chemicals that go into and come out of any given reaction

-allows us to count atoms by weighing them

AMU

atomic mass unit

mole

- 6.022 x 10^23

-a mole of any element contains 6.022 x 10^23 atoms of that element no matter what

-mass of a mole depends on the average mass of the element

enthalpy

-only interested in how much heat is going to change

- H=E+PV

-E: internal energy; P: pressure; V: volume

entropy

a measure of molecular randomness or disorder

elctrostatic force

-like charges repel

-different charges attract

bond length

the distance between 2 nuclei at the point of minimum energy

electronegativity

-the ability of an atom to attract shared electrons

-electrons are more attracted to the atom with the higher electronegativity

ionic bonds

-formed by the transfer of electrons from a metal to a nonmetal

-positive and negative ion

-soluble in H2O

-crystalline

-can conduct electricity

covalent bonds

Polar

-uneven sharing of electrons between 2 nonmetals or metalloids

Nonpolar

-equal sharing of electrons between 2 nonmetal or metalloid atoms

-softer solids, liquids, or gases

-not soluble in H2O

-cannot conduct electricity

metallic bonds

-metal to metal

-force of attraction between valence electrons and metal atom

-high melting/boiling point

-electrical conductivity

boyle's law

-when pressure increases, volume decreases

-PV=k

ideal gas law

-PV=nRT

-P: pressure V: volume; n: # of moles; R: constant; T: temp

-R: 8.3145 LxkPa/KxMol

-STP: 273.15K

R=

8.3145 LkPa/KMol

STP=

273.15K

1ATM

molarity

-the # of moles of a solute that are in a solution

-amount of solute in moles/volume of solution in Liters

-1M=1mol/1L

dilutions

-add more of a solvent or reduce solute

-as you dilute, # of moles remains the same but molarity shrinks

-M1V1=M2V2

acids

anything that donates a proton (a hydrogen atom without it's electron)

bases

anything that accepts a proton

cation

-usually alkaline metals

-lose electrons

anion

-usually halogens

-gain electrons

transition metals

-have multiple different forms

-ex. Fe^2+ --> Iron(II) Fe^3= --> Iron(III)

electrolytes

-ions in water

-an important way to classify liquids

sig figs

-the digits in a # that we actually know

- +/-: only the # of figures after the decimal points that matters, the # with fewest figures after the decimal point decides how many you can have in your answer

- x/: same # of sig figs as least precise measurement

Heinsberg uncertainty principle

it is impossible to know the exact position and velocity of an electron

chlorate

ClO3-

bromate

BrO3-

Iodate

IO3-

Nitrate

NO3-

Phosphate

PO43-

Sulfate

SO42-

Carbonate

CO32-

combination reactions

a reaction of 2 reactants to produce 1 product

decomposition reactions

when a molecule is broken down into smaller molecules, atoms, or ions

substitution/replacement reactions

an element replaces a less active element in a compound

double substitution reaction

-similar to substitution reactions

-2 elements switch their bonds with 2 compounds

combustion reactions

occurs when a substance reacts with oxygen to produce energy in the form of heat and light

neutralization

a reaction between an acid and a base

specific heat capacity

-quantity of heat required to raise 1 gram of a substance by 1 degree C

-represented by c

specific heat of H2O

4.184J/g*c

formula for specific heat regulation

heat regulation = mc(change in temp)

m: mass

c: specific heat

charles' law

V1/T1=V2/T2

combined gas law

P1V1/T1=P2V2/T2

graham's law

r1/r2=MM1/MM2

r: volume

MM: molar mass

la chatelier's principle

if an equilibrium system is stressed, a reaction will occur in the direction which tends to relieve the stress