SARA ABU-GHNAIM
A Brief History of Chemistry
Section 1
Bronze Casting
1) A worker is stoking the fire and two others are operating the bellows
2) Bronze ingots are melted by placing a ceramic melting-pot over the fire
3) The crucible with the molten metal is lifted off the fire with two poles
4) The liquid bronze is poured through funnels into the clay mould
Egyptian Blue Scarab
Egyptian Ceramic Vase
Philosopher’s Stone and an Arabic Alchemy Book
Fire Arrow
Antoine and Madame Lavoisier
Atomic Structure
Intermolecular Force
The Periodic Table
Potential Energy Model for a Chemical Reaction
Section 2
Mass Spectrometry
Is able to separate and measure atoms and compounds because moving charged species (ions) of different mass (and energy) are affected differently by magnetic or electric fields
Basically 3 steps: compounds or atoms are given charge (ions), accelerated, and a detector measures number of ions present
Properties and Importance of Commonly Recognized Isotopes- 2H,
14C, 60Co Isotope- form of an element whose nucleus contains a different number
of neutrons from an atom of that element, but has the same number of protons.
2H (deutrium) may become very important as a fuel for fusion power production since it combines in a fusion reaction with another isotope of hydrogen, tritium, to release large amounts of energy
14C is used in dating of materials containing carbon because when a living system dies, it ceases to maintain equilibrium with the 14C being produced by cosmic rays, so the amount of the isotope decreases at the half-life rate (5730 years). Thus, by measuring the amount of 14C left, archeologists can determine when the material ceased to be alive.
60Co does not occur in nature and has been used to kill cancerous tumor cells. Also kills harmful bacteria, so the isotope is used to sterilize foods for longer storage and medical equipment prior to use in surgery.
Isotope Notation
Wave and Particle Nature of the Electron and Photon
Mysterious to scientists- wavelike properties and particle properties could be exhibited simultaneously in experiments!!! WHAT! How is that possible!!
We believe that all matter can be represented by wave equations, but recognize that matter also exhibits properties typical of a particle
Quantum physics deals with this http://www.pbs.org/wgbh/nova/programs/ht/tm/3501.html?site=10&
pl=wmp&rate=lo&ch=18
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Electronegativity
Is the measure of one atom’s attraction of electrons from the adjacent atom to which it is chemically bonded
EN is a way to measure the winner in a “tug of war” for bonding electrons
If the EN values of the two atoms forming a bond are widely different, then the one with the higher value will win the electrons away from the other, forming an ionic bond.
With a smaller difference in the EN values, there would be a covalent bond (electron sharing).
If EN values are identical, there is a non-polar covalent bond.
The Importance of Hydrogen Bonding in Living Systems
The DNA molecule consists of chains of nucleic acids. Each of these contains the necessary ingredients for hydrogen bonding, namely: H atoms, O atoms, and N atoms.
Watson and Crick made a model that suggested that the hydrogen bonds between parts of DNA formed a double helix structure
There is hydrogen bonding between thymine, adenine, cytosine, and guanine
The Formation of Molecular Orbitals
When two or more atoms combine to form a chemical molecule, the electrons are arranged differently. The models that trace out the “electron waves” that constitute these electron positions are called molecular orbitals (MOs).
Sigma MO- overlap in which the new MO is concentrated along an imaginary line connecting the atoms
Pi MO- overlap where the electron wave shape is concentrated between the atoms, but away from the center line
F2- one sigma bond 02- one sigma and one pi bond N2- one sigma and two pi bonds Molecular orbitals are much more complex, so don’t worry
your little brains about it
The Resonance Concept Model
Resonance applies in some instances to bonding in molecules with more than 2 atoms
It was thought that bonds oscillated between two sides of the O3 molecule, but we now know that bonding is truly equivalent and it can best be thought of as 1.5 bonds on each side.
SO3 can be thought of similarly with 1 1/3 bonds on each side.
A very modern theory has come to replace to resonance model, so just know that it is WRONG
Decay Equations and Predicting Products of Decay
Unstable nuclei result in radioactive decay.Alpha decay results in the loss of two neutrons and
two protons from the parent nucleusBeta minus decay results in the loss of one neutron
and the gain of one proton from the parent nucleusPositron (or beta plus) decay results in the gain of one
neutron and the loss of one proton from the parent nucleus
Predictions of beta decay are based on the understanding that a nucleus is unstable because of an imbalance between the number of neutrons and the number of protons .
Alpha Bombardment Reactions
In these reactions, the mass stays the same, which conserves the number of protons and neutrons, which do not convert in alpha decay (they do convert in beta decay)
Fission and Fusion Reactions
Very simply, fission splits a massive element into fragments, releasing energy in the process. Fusion joins two light elements, forming a more massive element, and releasing energy in the process.
In fission of 235U, the products fly apart with a large amount of kinetic energy and this heat can be used to raise the temperature of water.
Fusion of 2H and 3H takes a lot of energy to overcome the positive charges and has not yet yielded enough energy to produce electrical power.
Section 3
Partial Pressures…
Dalton’s Law tells us that the total pressure is proportional to the number of particles of each gas
The value of the water pressure only depends on the temperature of the liquid. So you can just look this up in a table…
The Behavior of Gases under Extreme Conditions
There are 3 key assumptions with Kinetic Molecular theory (KMT)
However, most gases do not behave ideally in extreme conditions
Van der Waals developed a useful equation to monitor the behavior of non-ideal gases
Gases with large Van der Waals constants are good choices for refrigerator liquids
Carbon Dioxide
Liquid CO2 cannot be observed unless the pressure is at least 5.11 times the normal atmospheric pressure on Earth and at lower temperatures
Above the critical pressure point (point C on yall’s graphs), C02 becomes supercritical- acts as a liquid and gas, which is ideal for a solvent
When liquid CO2 is used, it is often recycled so it doesn’t hurt the environment
Raolt’s Law and Colligative Properties
Colligative properties are properties that depend on the amounts of substances present
Colligative property effects depend on the number of particle species present, not the moles of the original salt
Raolt established that the key factor determining the physical properties of a solution was the relative number of moles of solute in the solution
Reverse Osmosis vs. distillation of water
Section 4 (Last Section WHOOHO)
Acid-Base Reactions and Salts
When salt dissolves in water, its ions can interact with water molecules in a reaction called hydrolysis
Generally, the anions of weak acids will form basic salts
Cations of weak bases will form acidic saltsThere is no reaction when the cation of a
strong base and the anion of a strong acid join in water
Precipitates
The control of pH is important for plant growth
Perhaps the most well known contaminant is mercury (Figure 21)
Other precipitates are hazardous and can be inhaled, where they may stick to one’s lungs
Precipitation to remove toxic substances is a common process
Electroplating
Is the process of passing an electrical current through a solution containing a cation like Cu2+ and reducing it to Cu while coating an object with a thin layer of the metal
The amount of energy in electroplating is dependant on amount to be electroplated and number of electrons need to reduce a metal ion to its element
The electric charge on one mole of electrons was named the Faraday in honor of Michael Faraday
The Nernst Equation
Nernst equation connects cell potential to free energy changes for chemical reactions
One conclusion that can be drawn is that even if a cell has the same chemical in each compartment, if the concentrations are not equal, then there will be a cell voltage, even though E0=0. Such a cell is called a concentration cell.
Hess’s Law
This law states that the heat evolved or absorbed in a chemical process is the same whether the process takes place in one or in several steps
This is essentially a restatement of the law of conservation of energy!!!
This law allows us to calculate enthalpy changes that have not been measured based on our knowledge of other enthalpy changes that have been measured and using a cycle of reactions.
TIME FOR A HAPPIER SLIDESHOW!!!!
References
http://www.ehow.com/about_4728246_what-metal-casting-used.html http://www.reshafim.org.il/ad/egypt/trades/bronze_casting.htm http://www.signicast.com/casting_education/index.php http://en.wikipedia.org/wiki/File:Bronze_casting_by_the_Lost_Wax_Method.png http://weber.ucsd.edu/~dkjordan/arch/metallurgy.html http://en.wikipedia.org/wiki/Alchemy http://en.wikipedia.org/wiki/Glass http://en.wikipedia.org/wiki/Potter's_wheel http://en.wikipedia.org/wiki/Philosopher%27s_stone http://www.pyrouniverse.com/history.htm http://www.unomaha.edu/philosophy/NaturePhil.htm http://www.exampleessays.com/viewpaper/49419.html http://mattson.creighton.edu/History_Gas_Chemistry/Lavoisier.html http://www.biographybase.com/biography/Lavoisier_Antoine_Laurent.html http://www.cartage.org.lb/en/themes/Sciences/Chemistry/Generalchemistry/Energy/
LawofConservation/LawofConservation.htm http://www.grc.nasa.gov/WWW/K-12/airplane/thermo.html Science Research Guide