Chemistry unit 2

What effects Effusion?

The mass of the molecule

What is the difference between effusion and diffusion?

Effusion is through a pin hole and diffusion is through an open space

When will gasses behave most ideally?

High temperature and low pressure

What is heat capacity?

the number of heat units needed to raise the temperature of a body by one degree.

what is specific heat capacity?

The amount of energy required to increase the temperature of 1kg of a substance by 1oC

what is oxidation? (OIL RIG)

loss of electrons

what is reduction? (OIL RIG)

gain of electrons

How to calculate the oxidation number?

Look at the charge of a molecule and take use known from the periodic table.

Nuclear Charge is

the ability of protons in nucleus to attract negative electrons. (charge of protons)

Atomic size

Decrease along the period and increases along the group

cation

A positively charged ion

anion

A negatively charged ion

Ionization energy is

energy required to complete removal of 1 mol of electrons from 1 mol of gaseous atoms or iions

Ionization energy

decreases down group and increases across period

Larger atoms

hold electrons less tightly

smaller atoms

hold electrons tighter

Electron Affinity is

the energy charge that occurs when 1 mole of electrons is added to 1 mol of gaseous atoms or ions.

Electron Affinity

Decreases down group and increases along period

Paramagnetism

attracted by a magnetic field

diamagnetism

not attracted (and is slightly repelled) by magnetic field.

Ionic bond

transfer of electrons and is usually observed when metal bonds to nonmental

covalent bonding

sharing of electrons, usually observed when a nonmetal bonds to a metal

Electronegativity is

the ability for an atom to pull electron toward it

Electronegativity

increased across the period and decreases down the group.

What is the most electronegative element?

Fluorine (F)

Bond order

the number of shared electron pairs between two atoms

Bond energy

energy needed to overcome attraction between nuclei and shared electrons

Bond order: Shorter bond =

stronger strength

Bond energy: Stronger bond=

higher bond energy

Higher bond order results in

shorter bond length and higher bond energy

In LDD, what element goes in the center?

The least electronegative

How to calculate bond order

sum of bond types/number of bonds

Formal charge

charge of atom if all electrons were shared equally

How to calculate formal charge?

#valence electrons-(#unshared electrons+1/2# of shared valence electrons)

change in heat of reaction =

sum of change heat of reactant bonds broken (heat of reactants) + sum of change in heat of product bonds formed (heat of products)

Shape of molecule with 2 electron clouds

linear (180 degree)

Shape of molecule with 3 electron clouds

Triangular planar (120 degree)

Shape of molecule with 4 electron clouds

tetrahedral (109.5 degrees)

Shape of electron with 5 electron clouds

triagonal bipyramid

shape of six electron clouds

octohedral

Electrolytes

substance that produces a solution that conducts electricity when it is dissolved in water

What is Dilution?

process of adding water to a concentrated solution to achieve the molarity desired for a particulate solution

How to Calculate dilution

M1V1=M2V2

What is neutralization?

acid + base = salt + water

What is the Gas Law equation?

PV=nRT

Density of Gas equation

d=PM/RT

Moles of gas

mass/Molar Mass

Boil Law

Pressure is proportionate to 1/v

Volume is proportionate to moles

Volume is proportionate to temperature

What is 1 atm in mmHg?

760mmHg

combine gas law

P1V1/T1=P2V2/T2

What is 0 degrees C in K?

273K

Partial Pressure is

the total pressure in a mixture is the sum of the partial pressures of the component gases.

Partial Pressure equaiton

Pa=Xa*Ptot

Higher temperature=

Higher speed

Lower temperature=

lower speed

Endothermic reaction

heat is ABSORBED from environment

Exothermic reaction

heat is RELEASED into environment

Energy=

Heat+Work

Enthalpy=

E+PV or P/\ V

Higher specific heat means

it takes more heat to change the temperature.