Chem 121 Final

Be able to determine the energy absorbed or released when in electron moves between any two allowed levels in a hydrogen atom

-2.18x10-18 J (1/n^2) - -2.18x10^-18 J (1/n^2)

Given 🔺Hrxn be able to determine how much heat would be given off or taken in when a specified amount of reactant is consumed, or when a specified amount of product is produced

2H2(g)+ 02= 2H2O(g). 🔺H= -483.6kJ a. Calculate the heat associated with the complete reaction of 1.875 g of hydrogen gas 1.875g x (1 mol/2.016)x (-483.6kJ/2 mol)= -224.9kJ b. How much H2O is produced when 50.0 kJ of heat is admitted? -50kJ x (2 mol/ -483.6kj)= 0.207 mols

Be able to give a set of quantum numbers that describes a given electron

3d n=3 l=2 ml= -2,-1,0,1,2 ms= -1/2 or 1/2

Be able to explain what the square of the wavefunction represents

A mathematical function that describes the wavelike nature of an electron

Know and be able to use the equations that relate energy, frequency and wavelength

C=¥V Speed of light=wavelength(frequency) Ephoton=hv where h=6.626x10^-34 J*s

Know what is meant by the terms electromagnetic radiation, frequency, wavelength

Electromagnetic Radiation: A form of energy embodied in oscillating electric and magnetic fields Frequency: for waves, the number of cycles that pass through a stationary point in one second Wavelength: The distance between adjacent crests of wave

Be able to explain the model Bohr proposed for the atom and white parts of it violates classical physics

Electrons fall from one stable orbit to another then goes back, giving off energy in the form of light. No radiation was emitted by an electron orbiting the nucleus in the stationary state, it was only when the electron jumped, or made the transition from one stationary state to another, that radiation was emitted or absorbed

What determines the energy of a photon that is emitted the hydrogen atom?

Energy difference between the final and initial energy levels

Be able to define the terms exothermic and endothermic

Exothermic: A chemical reaction that releases heat into it surroundings, for an exothemic reacions, 🔺H<0 Endothermic: A chemical reaction that absorbs heat from its surroundings, for an endothermic reaction, 🔺H>0

Understand and be able to explain the types of relationships between energy, wavelength, and frequency

Frequency and wavelengh are inversely proportional (longer wavelength, shorter frequency) Energy of photon and frequency are directly related (high energy, high frequency, short wavelengths)

Know typical units for frequency, wavelength, and energy of electromagnetic radiation

Frequency- Hz, Hertz, s-1, or 1/s. They are all the same Wavelength: meters or nanometers. 1 m=10^9 nm Electromagnetic: 3.00x10^8 m/s

Know, in general, the ordering of the types of electromagnetic radiation shown in figure 7.5

Low energy to High energy Radio, microwave, infrared, visible light, ultravoliet, xray, gamma ray

Is it possible to draw a boundary surface diagram of the 1S orbital at the 100% probability limit

No. To reach the 100% probability limit you would have to be infinitely far away from the nucleus

Know what is meant by the term quantum numbers and orbital

Quantum numbers: one of four interrelated numbers that determines the shape and energy of orbitals, as specified by a solution of the Schrödinger model Orbital: A probability distribution map, based on the quantum mechanical model of the atom, used to describe likely position of an electron in an atom; also an allowed energy state for an electron

Be able to describe the basic shape of S and P orbital

S: spherically symmetrical P: two lobes of electrin density on either side of nucleus

Given🔺H be able to determine whether the reaction is endo or exothermic

Solid- liquid- gas is endothermic(+) Gas-liquid- solid is exothermic(-)

Be able to explain what is meant by the 'wave particle duality'

Sometimes light appears to behave like a wave, other times like a particle which behavior we observe depends on the particular experiment performed. it travels as a wave and interacts as a particle.

Know what 🔺H represents

The change in enthalpy 🔺H= 🔺E+P🔺V

Be able to define the standard mole Enthalpy of formation

The change in enthalpy when 1 mol of a compound forms from the constituent elements in their standard states

Millikans Oil Drop Experiment

The charge of the electron

Thomson's cathode Ray experiment

The charge-to-mass ratio of the electron

Know why gaseous species exhibit line spectra, be able to explain implications of these lines spectra

The emission spectrum of a particular element is always the same, it consist of the same bright line at the same characteristic wavelength. The white line spectrum is continuous, the emission spectra is not continuous, they consist of bright lines at specific wavelengths with complete darkness in between. The electron moves around the nucleus in circular orbits that can have only certain allowed radii.

Why doesn't the hydrogen atom produce light at all wavelengths?

The energy levels are discrete, not continuous, and electrons can only go from one energy level to another

Rutherford's gold foil experiment

The nucleus

Be able to explain the significance of each of the four quantum numbers

The principal quantum number(n): an integers that specifies the overall size and energy of an orbital. The higher the quantum number n, the greater the average distance between electron and the nucleus and the higher its energy Angular momentum quantum number(l): And integer that determines the shape of an orbital Magnetic quantum number(ml): an integer that specifies the orientation of an orbital Spin quantum number(ms): Denotes the electron spin as either 1/2 or -1/2

Be able to state, and words and as an equation, the uncertainty principle and explain why it must be true

The principle stating that due to the wave-particle duality, is fundamentally impossible to precisely determine both position and velocity of a particle at a given moment in time 🔺x * m🔺v greater than or equal to h/4pi An electron is observed as either a particle or wave, but never both at once

Be able to explain why we do not observe the matter waves of an object such as a golf ball or baseball

The uncertainty principle

Describe the difference between emission and absorption of light by an atom

When the atoms absorbs energy, in the form of heat, light, or electricity, it reemits that energy as light

Given a set of quantum numbers be able to state what type of electron it describes

l=0. s l=1. p l=2. d l=3. f

Know and be able to apply the selection rules for the quantum numbers

n= 1,2,3... l= 0,1,2....(n-1) ml= -/...0...+/ ms=-1/2,1/2

Be able to determine whether a given set of quantum numbers is or is not allowed

n=2, l=1, ml=0, ms= 1/2- allowed n=3, l=1, ml=-2, ms=-1/2- not allowed, ml can only be -1,0,1 if l=1

Be able to calculate the allowed energy states for the electron in hydrogen atom

¥= h/mv or E= hc/¥ Wavelength= (6.626x10^-34)/ mass(velocity)

Be able to determine🔺Hrxn from standard enthalpies of formation

🔺Hrxn=products-reactants