CHEM 121 FINAL

list the oxidation numbers

list the oxidation numbers

• group 1 - 1

• group 2 - 2

• hydrogen 1 (Unless its H2O2)

• Oxygen - -2

• Fluorine - -1

• Chlorine - -1

explain boyles law (P1V1=P2V2)

• volume of an ideal gas is inversely proportional to its volume at constant temp

explain charles law (V1/T1 = V2/T2)

• volume of an ideal gas at constant pressure is directly proportional to absolute temperature

explain gay-lussac’s law (P1/T1 = P2/T2)

• Volumes of gases at constant temp and pressure are in simple ration of each other

what is avogadros law (V1/n1 =V2/n2)

• when P and T are constant, all have the same number of molecules

What is the kinetic molecular theory (KMT)?

• pressue = collisions of particles on the wall of the container

• do not exert force on each other

what is effusion of gasses?

• gas molecules going through a small evacuated chamber (pinhole).

what is diffusion of gasses?

• migration of gas molecules as a result of the mixing o two gases

What are real gasses? How do they differ from ideal gasses? Why do we not use pv=nrt?

• behave at low pressure unlike ideal which behaves at high pressure

• they attract other particles

• because pv is not equal to nrt anymore as they include corrected pressure, volume and constants

what happens when a piston pushes down on a cylinder? Is work done on the system or the surroundings?

• work is done on the system

• if V2-V1 is negative, work is done on the system

• if V2-V1 is positive, work is done on the surroundings

what is internal energy? (u or E)

• sum of potential and kinetic energy (q+w)

what is enthalpy?

• the internal energy of the system +work (H=E+PV)

• how do you change the KE of an ideal gas?

• change the temperature

• what is molar heat capacity?

• energy required to raise the temp of 1 mol of a substance

what is a state function?

• a system that remains the same no matter what path you take

• change in energy may be different but the answer is the same

what is a calorimetry?

• used to measure heat absorbed or released in a chemical reaction by measuring the change in temperature insulated in water

What is Hess’ Law?

• enthalpy remains the same no matter where you go/what steps you take

describe the components of electromagnetic waves

• transport energy through empty space in a propagating electric field and magnetic field

• travels until its absorbed

• change in magnetic field = change in electrical field

• self-propogates

How is light a wave? Describe it

• diffraction

• diffraction is when electromagnetic radiation is scattered from a regular array of objects

whats contructive interference? Whats destructive interference?

• constructive - when the peaks and troughs line up to make a bright area and increase intensity

• destructive - when the peaks and troughs cancel each other out to make a dark spot and decrease intesity

Why is C (constant for the speed of light) not constant?

• light travels slower in water than in any other medium

What does HHS and LLL describe in wavelengths?

• high energy, high frequency, small wavelength

• low energy, low frequency, low wavelength

What is black body radiation?

• radiation that is absorbed and is emitted at certain wavelengths

what is quanta?

• that the blackbody can absorb and emit packets of energy (Quanta)

what is the photoelectric effect?

• when a photon is shone onto a metal surface, it causes an electron to eject out from the metal

• Intensity doesn’t matter - it relies on frequency

• requires minimum frequecy

Why is Bhors model suitable for electrons from hydrogen, He, Li, and Be but not other elements as electrons go from ground state to excited state?

• fails to show the emission of more than one electron

Are electrons waves?

• Yes they are, they are standing waves

• cannot have any frequency that you want as the ends are fixed and have nodes

• form interference patterns

What is the quantum n?

• principal

• 1,2,3…

• determines size and energy level

What is the quantum l?

• angular momentum

• 0, n-1

• determines 3D shape

• 0=s, 1=p, 2=d, 3=f

What is the quantum ml?

• magnetic

• -1, 0, 1…

• orientation of orbitals

What is the quantum ms?

• spin

• +1/2, -1/2

what are the two exceptions to electron configuration?

• chromium and copper

• 4s13d5 and as1sd10 are more stable rather than having a 4s2 shell full

what is ionization energy? What does the trend look like?

• energy needed to remove an electron

• bottom left hand side and goes diagonally up to the right

what is electron affinity? whats the trend?

• energy change to add an electron

• increases up and to the right

how is radius size change?

• increases when you go down a group and decreases moving left to right

what is lattice energy?

• converting from a solid to a gas

• larger the ion, lower the lattice energy

why are triple bonds stronger than single?

• because electrons are held closer together to the nuclear which causes then to be shorter and stronger

list the bond angles of linear, trigonal planer, trigonal bipyramidal, tetrahedral, octahedral

• linear - 180

• trigonal planer - 120

• trigonal bipyramidal - 120, 90

• tetrahedral - 109.5

• octahedral - 90, 180

why do orbitals overlap?

• increase of electron probability

name the % of s and p in sp3, sp2, sp

• sp3 - 25%s 75%p

• sp2 - 33%s 67%p

• sp - 50%s 50%p

describe the orientation of sigma bonds

• head to head overlap

describe the orientation of pi bonds

• side by side overlap

name the 3 types of intramolecular forces

• ionic

• covalent

• metallic

why cant ions get infinitely close

• intermolecular distance

name the 6 types of intermolecular forces

• ion dipole

• dipole dipole

• h bonding

• LDF

• induced dipoles

• ion induced

what is ion dipole?

• when an ion is attracted to a molecule

what dipole - dipole?

• attraction between two POLAR molecules

what is H Bonding

• when H is attached to NOF and has a lone pair

what is LDF

• attraction between two non-polar molecules

what is induced dipole

• forcing an attraction between polar-polar or nonpolar-nonpolar when they have a weak attraction

what is ion induced dipole

• forcing an ion to with weak attraction to a non-polar/polar molecule

rank all 6 intermolecular forces from greatest strength to least amount of strength

• ion dipole

• h bonding

• dipole dipole

• ion induced dipole

• induced dipole

• LDF

what is the strength of covalent bonds and intermolecular attraction?

• covalent bonds are STRONG bonds

• intermolecular forces are WEAK

what prevents liquids and solids from being heated

• intermolecular forces

• intermolecular forces are strong enough to keep them from expanding significantly

why are liquids and solids less compressible

• little empty space between molecules

describe fluidity

• gravity causes molecules to move/fallan opening is left free

• the next molecule/closes molecule moves into the opening and repeats

what is an amorphous solid?

• a substance that lacks an ordered internal structure

why is a water droplet spherical

• uneven distribution of molecular forces

• surface molecules are pulled inwards

• inner molecules are pulled in all directions

what is adhesion? What is cohesion?

• cohesion is the attraction of like molecules that cause a net attraction on the surface

• adhesion is the attraction of unlike molecules, which when something is polar and is dropped onto a water droplet it will disperse out

what is surface tension?

• resistance of a liquid to an increase in its surface area

whats the difference between a non-wettable surface and a wettable surface

• non-wettable: when the surface tension dominates the attractive force on the surface

• wettable: when the attractive forces of the surface is greater than the surface tension of the water

what is viscocity?

• the resistance to flow

• liquids with higher intermolecular forces and complex molecules have high viscosity

• viscosity is temperature dependent as increased molecular motion disruptions disrupt molecular interactions

name the three types of solids

• crystalline

• polycrystalline

• amorphous

name difference between crystalline and amorphous solids

• crystalline: definite melting points, rigid, definite shape, incompressible

• amorphous: no definite geometrical shape, wide range of fusion points,

what is anisotropic and isotropic

• anisotropic: their mechanical propteries depend on the way they’re measured

• isotropic: similar physical properties in all directions as that are arranged in a random matter

whats the smallest repeating unit of a lattice called?

• unit cell

describe differences of evaporation and boiling

• evap: when molecules are able to leave the solution

• boil: when bubbles form in the solution and increases vapor pressure

whats the boiling point of a solution

• when the vapour pressure is equal to 1atm

what is a phase diagram?

• phases of a pure substance as a function of temp and p

what is the critical point?

• when it is a fluid (liquid and gas propteries)

what is the triple point

• when it exists in all three states

why is the phase diagram of water different than a pure substance?

• the solid form of water (ice) is less dense than water in its liquid form because of its hexagonal lattice structure shape

what’s the difference between immiscible and miscible solutions

• immiscible - solutions that do not mix due to different intermolecular bonds

• miscible - solutions that mix due to similar intermolecular forces

describe the formation of a liquid

• solute breaks IMF bonds - endo

• solvent breaks IMF bonds - endo

• solvent and solute molecules join - exo

what if you delta H is greater than delta H 1+2

• your solution is heterogenous(non ideal solution)

how does IMF effect solutbility?

• if unlike substances are mixed, their bonds actually cause MORE ORDER than disorder

whats the relationship between concentration and pressure

• proportional related

whats the relationship between concentration and temp? Why?

• inversely related

• increase in temp causes molecules to escape from the solution

• why we keep soda in the fridge as pressure allows more gas into the solution

in ideal solutions, forces between solvent molecules are _____ than solute and solvent

• equal

• requires the same energy for solvent molecules to break away

what happens to vapour pressure when solute is added

• lowers as the solute begins to take up more space and won’t allow molecules to leave the solution

what does weak A-B mean? What does strong A-B mean?

• weak A-B: positive deviation with weak IMF

• strong A-B: Negative deviation with strong IMF, lower vapour pressure

what are colligative properties of a solution

• boiling point elevation

• freezing point depression

• osmotic pressure

why is van’t hoff factors slightly lower?

• ions do not dissociate 100% and therefore still remain in pairs

what do nuclear changes affect?

• alter number of protons in a nucleus of an atom

• AKA nuclear transmutation

what do nuclear reactions involve?

• involve protons and neutrons

• atomic number changes

• different isotopes behave differently

• small amount of matter is converted to energy

what is radioactive decay?

• when natural isotopes spontaneously alter the number of protons to become more stable

what are the 4 particles and their identity?

• alpha - helium nucleus

• beta - electron

• beta (+) - positron

• gamma - high energy photon

what is alpha decay, beta decay, positron, and electron capture

• alpha: Alpha particle is ejected out

• beta: neutron becomes a proton by ejecting an electron

• positiron: When positrons are emitted

• electron capture: draws inner core electrons into the nucleus causing a proton turn into a neutron

What happens when attractive forces (Nuclear) And repulsive (ELectrostatic) are not balenced?

• atom undergoes radioactive decay to become balanced

what is the belt of stability?

• when N+Z where anything over or under the curve undergoes decay to stablize it

When elements get heavier, what happens in relation to the protons

• the heavier it is, the more protons required in the nucleus

describe how nuclides over 82 decay? Describe how nuclides under 82 decay?

• heavy - alpha decay to reduce atomic number

• neutron rich - beta decay

• proton rich - positron decay

what is radiometric dating?

• using principals of half life to predict rock formation

what is artificial radioactivity?

• induce bombardment of certain nuclei with atoms produced by nuclear reaction or particle accelerators

what are the 4 particles in artificial radioactivity?

• neutron - uncharged nucleon

• proton - hydrogen nucleus

• deutron - nucleas of 2H

• Positron - positivley charged ion

what is nuclear fission

• when neutrons are used into creating nuclear reactions

• chain reactions - when another neutron initiates a series of more reaction

What happens when something is fissionable? How do they maintain it?

• cannot undergo nuclear fission

• they keep material under critical mass (min mass)

what kinds of hydrogens can nuclear fission make?

• deuterium and tritium

give examples of natural radiation

• UV rays

• visible light

• infrared

• microwaves

• radio and TV rays

give examples of ionizing energy

• xrays

• gamma rays

• alpha and beta

• delta