general chem knowledge

1 mL

1 cm³

nucleon numbers/mass number (A)

protons+neutrons. property of individual isotope ¹⁴C → carbon-14

atomic mass

property of element as a whole

atomic number (z)

number of protons

molecular mass

can be mass of element multiplied by how many atoms present

ion

atoms with electric charge

cation

ion with positive charge (metal loses electrons)

anion

ion with negative charge (nonmetal gains electrons)

1 mL water

1 g

1 m (to in)

39.4 in

1 qt (to L)

0.946 L

C to F

convert, add

F to C

subtract, convert

diatomic elements

Have no Fear Of Ice Cold Beer (H₂, N_2, F₂, O₂, I₂, Cl₂, Br₂

oxidation

loss of electrons (gain of positive charge)

reduction

gaining of electrons (loss of positive charge)

ionic compounds

atoms of different elements join chemically due to attractions between oppositely charged ions

ionization

when neutral atoms become ions

propetoes of ionic compounds

metal and nonmetal, solid at room temp, high melting points (bc attractions between charges make it hard for ions to move out their positions), conduct electricity when in motion (liquid NOT solid). break up in solution

covalent compound

when two nonmetals share electrons. made up of molecules, do not break apart in solution

empirical formula

lowest terms/proportions of atoms/ simiplest whole number ratio ex. HO (instead of H₂O₂) ionic compounds only have this

molecular formula

absolute number of atoms in a molecule ex.H₂O₂

scientific law

explains what happens

hypothesis

educated guess of how something happens

theory

explains how something happens

compound

pure substance of different kinds of atoms chemically joined in definite proportion. molecules are alike

gas to liquid

condensation

solid to liquid

melting

gas to solid

deposition

liquid to gas

evaporation

solid to gas

sublimation

liquid to solid

freezing

1^o C

1.8F

beta decay

one neutron turns into one proton and one electron

carbon burning

two carbon-12 nuceli combine and produce two products

alpha decay

nucleus of atom ejects a helium-4 nucleus. (subtract the helium)

ite becomes…

ous + acid

ate becomes…

ic + acid

ide becomes…

hydro + ic + acid

when finding proportions put the —— number on top and round to the nearest whole number ratio

larger

find emperical compound given mass of different elements how?

convert to moles using atomic masses of each element and put greatest number of moles over the smallest

decomposition reaction

a more complex reactant is being broken down into simpler products

synthesis reaction

simpler reactants form a more complex product

what happens in a double displacement reaction?

cations and anions switch between two reactant to form new products. Ex: MgCl₂ + 2NaOH —> Mg(OH)₂ + 2NaCl

what happens in a single displacement reaction?

one element is substituted for another element in a compound (ex: 3Ca +2AlCl₃ —> 3CaCl₂ + 2 Al)

what should you do to find what reactant is limiting and which is excess?

if given in grams, convert to moles, then use mole ratio given from the balanced chemical reacction. whichever is less is the limiting reactant.

what is percent yield?

actual/theoretical *100

nuclear fission

uranium-235 splits into two smaller atoms and two free neutrons

% w/v

mass of solute in g / volume of solution in mL * 100%

% w/w

mass of solute in g / mass of solution in g * 100%

% v/v

volume of solute in mL / volume of solution in mL

mole fraction (x)

xA = moles A / (moles A + moles B)

electrolyte

water-solube ionic compounds, a substance that produces ions when dissolved

what happens when an acid reacts with water?

get a positively charged hydronium ion and a negatively charged ion of some sort

acids are…

proton donors

bases are…

proton acceptors

what happens when a base interacts with water?

get a negatively charged hydroxide ion and a positively charged ion of some sort

solvent and solute polar

solubiliity likely

solvent and solute nonpolar

solubility likely

solvent polar and solute nonpolar

solubility not likely

molarity (m)

moles solute / L solution

what do electrolytes do in aqueous solution?

conduct electricity

molality (m)

moles solute / kg solvent

formula for dilutions

C1V1=C2V2

H2CO3 (carbonic acid) decomposes into…

H2O (l) + CO2 (g)

H2SO3 (sulfurous acid) decomposes into…

H2O (l) + SO2 (g)

NH4OH (ammonium hydroxide) decomposes into…

H2O (l) + NH3 (g)

what compounds are always water soluble?

Li+, Na+, K+, NH4+, NO3-, C2H3O2-

solubility rule #3

Cl-, Br-, I- often soluble (except Ag+, Hg22+, Pb2+)

solubility rule #4

SO42- often water soluble (except Sr2+, Ba2+, Pb2+, Ag+, Ca2+)

solubility rule #5

OH-, S2- often NOT water soluble (except Li+, Na+, K+, NH4+)

solubility rule #6

PO43-, CO32- often NOT water soluble (except Li+, Na+, K+, NH4+)

what happens in a redox reaction?

a more active metal will spotaneously give electrons to a less active metal

P=

F/A

boyles law

P1V1=P2V2

charles’s law

T1/V1 = T2/V2

avogadro’s law

n1/V1 = n2/V2

what are the conditions of STP?

T=0.00 C = 273.15 K and P=1.00 atm. For one mole of an ideal gas, V=22.4 L (use if question asks for density)

PA=

(Ptotal)(xA)

mole fraction

moles A / (moles A + moles B +…)

Urms= (m/s)

sqrt(3RT/molar mass m) use kg/mol

J= (unit conversion)

1kg(m/s)²

q (J) =

c(heat capacity)*deltaT OR m(mass)*Cs*deltaT

rate of effusion

rate A / rate B = sqrt(molar mass B / molar mass A)

when does PV=nRT fail?

very high pressure, very low temp

what does gas pressure result from?

constant collision of of gas molecules against any surface with which the gas is in contact

what happens at very high presssure?

V is often larger than PV=nRT predicts

what happens at very low Temp?

molecules move slowly enough that intermolecular forces act as a brake on motion…P is often lower than PV=nRT predicts

absorbing energy is

KE to PE

releasing energy is

PE to KE

any charged object is more —— when its close to an oppositely charged object

stable

what does stable mean?

low in PE

what does breaking bonds do?

stores energy

what does forming bonds do?

release energy

deltaE=

q+w OR q-pdeltaV

W=

P*D*A or -(PdeltaV)

Hess’s Law

If a chemical eq can be expressed as the sum of series of steps, then delta Hrxn for the overall eq (pathway) is the sum of the heats of the reaction for each step

large negative enthalpy / low chemical energy

stable

large positive enthalpy / high chemical energy

unstable

E (energy of photon) =

hv where v is freq