DAT General Chemistry

Hydroxide

OH^-

Nitrate

NO₃^-

Carbonate

CO₃^2-

Sulfate

SO₄^2-

Phosphate

PO₄^3-

Ammonium

NH₄⁺

Methane

CH₄

Ammonia

NH₃

Hydrogen Peroxide

H₂O₂

accuracy

closeness of data value to literature value

precision

consistency of all data values

log 2

0.3

log 3

0.48

1 Liter = ? mL and ? cm³

1000 mL and 1000 cm³

t (K) =

t (C) + 273.15 (K)

Pressure: 1 atm = ? torr / mmHg, ? kPa, and ? bar

760 torr / mmHg, 101.3 kPa, and 1.013 bar

Boiling Point of water

100 C

Freezing Point of water

0 C

Amount of substance

mole (mol)

thermodynamic temperature

kelvin (K)

mass

kilogram (kg)

length

meter (m)

time

second (s)

giga-

G = 10⁹

mega

M = 10⁶

kilo

k = 10³

hecto

h = 10²

deca

da = 10¹

deci

d = 10^-1

centi

c = 10^-2

milli

m = 10^-3

micro

u = 10^-6

nano

n = 10^-9

Have No Fear Of Ice Cold Beer

Diatomic gases: H2, N2, F2, O2, I2, Cl2, Br2

Metal Properties: (6)

• Malleable and lustrous

• Form basic oxides

• High melting and boiling points

• Lose electrons to form cations

• Good conductors of electricity 

• Solid at room temperature (exception: mercury)

Non-metal Properties: (6)

• Brittle and dull

• Form acidic oxides

• Low melting and boiling points

• Gain electrons to form anions

• Poor conductors of electricity and heat 

• Gas or solid at room temperature (exception: bromine) 

Atomic radius

½ the bond length between identical atoms;

increases to the left and down the periodic table

Effective Nuclear Charge

Z_eff = Z (proton #) - S (# of shielding electrons)

= the amount of positive charge experience by an electron;

increasing to the right and down the periodic table

isoelectronic series

atoms/ions with the same number of electrons but different proton numbers; anions have larger atomic radius, cations have smaller atomic radius

ionization energy/potential

the energy needed to remove an electron from a gaseous, neutral atom… = change in enthalpy (delta H)

increases to the right and up (1st ionization energy)

• 2nd ionization energy: after 1st electron is removed, the 2nd ionization is harder and higher energy; easier for 1st group and smaller elements than group 2, but still a high energy;

• alkaline earth metals have a higher than usual 1st ionization energy because of p orbital valence electrons;

• group 15 higher energy than group 16 because of half filled orbitals

• group 2 have higher energy than group 13 because of group 2 filled orbital

electron affinity

the amount of energy released/required when an electron is added to a gas-phase atom

increase to the right and up; becomes more negative

• noble gases have low affinity (they have all of their valence electrons);

• if an element can perfectly half fill their orbital with the electron, it will have a higher affinity than an adjacent element with an already half-filled orbital (group 4 > group 5)

electronegativity

the ability of an atom to attract electrons to itself in a covalent bond

increase to the right and up

• noble gases are negligible

Soluble Salts (5)

• group 1 metal cations

• NO₃^-

• ClO₄^-

• C₂H₃O₂^-

• NH₄⁺

Insoluble Salts (7)

• Ag⁺

• Pb²⁺

• Hg²⁺

• OH^-

• S^2-

• CO₃^2-

• PO₄^3-

Strong Acids: (7) + acronym

• HI Hi

• HCl Class (is)

• HBr Boring.

• HNO₃ No (it isn’t)

• HClO₃ Class (is) Over

• HClO₄ Class (is) Over

• H₂SO₄ So (what)

Strong Bases (4)

• Group 1 Metal Hydroxides

• Ba(OH)₂

• Sr(OH)₂

• Ca(OH)₂

Weak Acids: (3)

• HF

• HCN

• CH₃COOH

Weak Base: (2)

• NH₃

• CH₃NH₂

Colligative properties

depend upon the concentration of solute molecules or ions, but not the identity of the solute

ex: salt makes water harder to freeze

Non-colligative properties

depend on the identity of the dissolved species and the solvent

ex: surface tension varies between substances, color depends on substances

Surface Tension

property of a liquid that allows it to resist an external force, due to cohesion

non-colligative

Viscosity

measure of a liquids resistance to flow

non-colligative

Solubility

ability of a solute to for a solution with a solvent

non-colligative

Color and density

do not depend on the number of particles

non-colligative

Boiling Point

when the vapor pressure = atmospheric pressure; liquid is converted into gas

colligative

BP at sea level

100 C

BP above sea level

decreases; as elevation increases the atmospheric pressure decreases and this BP is easier to reach

BP below sea level

increases; as elevation decreases the atmospheric pressure increases because the air is denser

Vapor-Pressure Depression

vapor pressure without solute is higher than VP with a non-volatile solute; adding solute increases boiling point by lowering VP and requiring higher temp to reach atmospheric pressure; Raoult’s Law

colligative

Raoult’s Law (Vapor Pressure)

VP of solution = mole fraction of solvent x VP of solvent

colligative

Boiling Point Elevation

BP of a liquid will be higher when a non-volatile solute is added; large van’t Hoff factor increases BP

Change in BP = solvent’s BP-elevation constant x i x molal

colligative

Freezing-Point Depression

a drop in the minimum temp at which a substance freezes when a non-volatile solute is added; solution has a lower FP due to the solute

ex: alcohol lowers the FP of water

Change in FP = (-) solvent’s FP-depression constant x i x molal

colligative

Osmotic Pressure

the pressure required to stop osmosis

Osmotic Pressure (atm) = i x M x universal gas constant x temp (K)

colligative

van’t Hoff Factor

“i”

the number of particles a solute breaks down into

ex: MgCl2 … i = 3 because of Mg²⁺, Cl^-, and Cl^-

Normality

N= number of equivalents x M

Combined Gas Law

(P1V1)/(n1T1) = (P2V2)/(n2T2)

Boyle’s Law

P1 V1 = P2 V2

Charles’s Law

V1/T1 = V2/T2

Avogado’s Law

V1/n1 = V2/n2 where n is the number of moles

Gay-Lussac’s Law

P1/T1 = P2/T2

Dalton’s Law of Partial Pressure

total pressure of the mixture is equal to the sum of the partial pressures of individual gases

• P_total= P1 + P2 + …

• P1 = X1 x P_total where X1 is the mole fraction of gas 1

Gas density

Density = m / v

Density = (P x M) / (R x T)

Effusion

A confined gas escaping through a small hole, which gas effused faster are ones with lower molecular weight

Graham’s Law of Effusion

r1/r2 = √(M2/M1) where r is the effusion rate and M is the molar mass

inversely proportional

Ideal Gas Law

PV = nRT

STP

Standard Temp and Pressure: 273K, 1 atm, 1 mol = 22.4 L

1st Order Half-life

t_1/2= 0.693/k

Properties of Work (2)

1. ΔE = q + w (change in internal energy = heat + work)

2. w = -P x ΔV (work = -Pressure x change in volume)

Arrhenius Acid

produces H⁺ ions

Arrhenius Base

produces OH^- ions

Bronsted-Lowry Acid

a proton (H⁺) donor

Bronsted-Lowry Base

a proton (H⁺) acceptor

Lewis Acid

accepts a pair of electrons

Lewis Base

donates a pair of electrons

Henderson-Hasselbach Equation:

pH=

pH = pKa + Log ([A^-]/[HA])

determine the ratio of acid to conjugate base in a buffer solution

Heat absorbed/released:

q= mass x C x delta T

q= mass X delta H

*In calorimetry: q= C x delta T

Common Oxidizing agents: (4)

• O2

• O3

• H2SO4

• halogens

Common Reducing Agents: (4)

• H2

• Fe

• Zn

• Alkali metals (Group 1)

Bohr’s Principle

model of the atom describes electrons orbiting around the nucleus in a circular path

Pauli Exclusion Principle

no two electrons in an atom can have the exact same four quantum numbers

Heisenberg Uncertainty Principle

it is impossible to know both the location and momentum of an electron at the same time

Hund’s Rule

every orbital in a subshell must be occupied with an electron first before the electrons begin occupying in pairs

Aufbau Principle

electrons fill orbitals in the order of increasing energy levels

VSEPR: 2 bonding 0 lone

Linear: 180 deg

ex: CO₂

VSEPR: 3 bonding 0 lone

Trigonal Planar: 120 deg

ex: BF₃

VSEPR: 2 bonding 1 lone

Bent/V-shaped: <120 deg

ex: SO₂

VSEPR: 4 bonding 0 lone

Tetrahedral: 109.5 deg

ex: CH₄

VSEPR: 3 bonding 1 lone

Trigonal Pyramidal: 107.5 deg

ex: NH₃

VSEPR: 2 bonding 2 lone

Bent/V-shaped: 104.5 deg

ex: H₂O

VSEPR: 5 bonding 0 lone

Trigonal bipyramidal: 90 and 120 deg

ex: PCl₅