A.M.D.G ULTIMATE SCIENCE REVIEW • JOSEPH SZYMBORSKI 1/25 ULTIMATE SCIENCE REVIEW 436 AND 416 BY: JOSEPH SZYMBORSKI TOPICS: • Dimensional Analysis • Scientific Notation • Properties • Physical and Chemical Change • Elements and Compounds • Mixtures (Heterogeneous & Homogeneous) • Philosophers and Scientists • Electrostatics • Protons, Neutrons and Electrons • Bohr-Rutherford Diagrams • Cathode Ray Tube • Radioactivity • Copper Oxide Labs • Percent Yield • Names of the Elements (1-36) • Isotopes • Average Atomic Mass • Chemical Reactivity • Periodic Trends • Metals, Non-Metals and Metalloids • Four Families • Molecules • Balancing Equations • Mole • Stoichiometry • Structures of Matter• Nomenclature • Magnetism • Electromagnetism • Conductors/Insulators • Theory on I/V/R • Resistors • Ohm's Law • R eq Series/Parallel/Combo • Kirchoff Series/Parallel • Power Equations • Read a Hydrometer• Heat • Heat -> Electrical power• Concentration / Solutions / Dilutions • Acids, bases and salts • Indicators • pH DIMENSIONAL ANALYSIS: • Dimensional Analysis can always (and should always) be solved in one line • The focus is put on units (dimensions) • You should start with a certain unit, and end by canceling out units via conversion factors to end with the result that is asked of you EX: The density of air is 0.00129 g/ml. What volume (in liters) will 1g of air occupy? 1ml 1cl 1dl 1L 1g x ------- x -------- x -------- x ------- = 0.775193798 L 0.00129g 10ml 10cl 10dl
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A.M.D.GULTIMATE SCIENCE REVIEW • JOSEPH SZYMBORSKI 3/25
Electrolytes)
PHILOSOPHERS AND SCIENTISTS:
• Aristotle maintained that matter does not contain atoms and that anything can beinfinity divided (Continuous Theory)
• Democritus maintained that matter is made of atoms (Discontinuous Theory) and allthings are made of the same atoms in a different arrangement (the latter beingincorrect)
• Dalton believed in four main rules:1) All mater is composed of tiny indivisible atoms2) All atoms of the same element are the same3) Atoms of different elements are different4) During a chemical reaction, atoms combine and form bonds to create new
atoms
• J.J Thompson maintained three main beliefs:1) Protons are positively charged2) Electrons are negatively charged3) Atoms are neutrally charged because they have the same amount of protons as
they do electrons
• Created the plum pudding model (which is incorrect)
• Rutherford held the belief that:1) The atom is made mostly of space2) The Nucleus is mostly positive3) The nucleus is very dense4) The number of protons and neutrons vary from element to element
• Created the Rutherford model which involved electrons revolving around thenucleus in no particular order
• Niels Bohr added to Rutherford's model by introducing electron orbits and shells
ELECTROSTATICS: Ex:
• All matter is neutral
• Some attract a stronger negative charge thanothers (Silk, Wool,
Cotton, Rubber)
PROTONS, NEUTRONS AND ELECTRONS:Protons1uPositively ChargedInside the Nucleus
Neutrons1uNegatively ChargedInside the Nucleus
Electrons0u (1/1837 u)Negatively ChargedOutside the Nucleus
A.M.D.GULTIMATE SCIENCE REVIEW • JOSEPH SZYMBORSKI 7/25
92.58% of all lithium isotopes that exist are Li-77.42% of lithium isotopes are Li-6
Li-6 : 3 Protons, 3 ProtonsTotal: 6 Nucleons So it is called Li-6
• These percentages are called Relative Abundances
• Atomic Mass is not an integer because it is a weighted average
• Atoms of the same element have the same # of protons but neutrons vary
AVERAGE ATOMIC MASS = (MASS NUMBER ISTOPE 1 X % ABUNDANCE 1) +(MASS NUMBER ISTOPE 2 X % ABUNDANCE 2) +(MASS NUMBER ISTOPE 3 X % ABUNDANCE 3)
ETC...
EX: The percent abundance for the isotope of potassium with the least amount of neutron is94%, while the percent abundance of the isotopes with the second-least amount of neutronsis 5%. Calculate the average atomic mass of potassium.
39.10 = ( x-1 x 0.05) +
( x-2 x 0.94) +
( x-3 x 0.01)
CHEMICAL REACTIVITY:
• Reactivity is determined by valence shell
• Families have same valence, ergo the same reactivity
• Group number = valence
•For metals, reactivity increases from right to left in a period and top from bottom in afamily
A.M.D.GULTIMATE SCIENCE REVIEW • JOSEPH SZYMBORSKI 8/25
• For non-metals, reactivity increase left to right in a period and bottom to top in a family
• In chemical reactions, atoms tend to become as stable as possible. They try to acquirethe electron configuration of the closest inert gas in the period by either losing or gaining electrons
EX:
Li + F → LiF3 Na + N → Na3NMg + 2 Cl → MgCl2Ca + 2 Br → CaBr 2Ra + At → Ra2At
PERIODIC TRENDS:
• Certain trends can be observed in the periodic table concerning the atomic properties
• Atomic Mass: The mass in mol/g for each element increases from left to right
• Why? From left to right, up to down, the atomic number increases. This means that theprotons increase and protons make up the majority of the mass of the atom.
• Metallic Properties: Metallic properties like conductors of both electricity and heat.This increases right to left
A.M.D.GULTIMATE SCIENCE REVIEW • JOSEPH SZYMBORSKI 9/25
• Atomic Radius: Atomic radius (the proximity of the electron shells to the nucleus)increases right to left
• Why? The less positive the nucleus is, the further away the electron shell is, the larger
the atomic radius number is. The nucleus becomes more positive the higher the atomicnumber gets (from left to right)
• Ionization Energy: Energy required to remove 1 mol of electrons from materialcomposed in a single atom (measured in kJ/mol) increases from right to left
• Why? Right side (other than inert gases) already want to give away their electrons
•Electronegativity: Ability of an atom to attract electrons to itself. More or less oppositeof Ionization Energy. Measured on the Paulis Scales, a dimensionless scale from 0.7 to4 (like Richter scale).
• Why? Left side already wants to receive electrons
• Characteristic Properties: Density (g/ml), Boiling Point (ºc or K), Melting Point (ºc or K) etc are all greater in the middle of the table.
A.M.D.GULTIMATE SCIENCE REVIEW • JOSEPH SZYMBORSKI 10/25
METALS, NON-METALS AND METALLOIDS:
• Metals are characteristically electrically and thermally conductive, usually solids atroom temperature, are generally malleable, ductile and lustrous and are found typicallyfrom the 1st to 13th family
• Metalloids have some of the same characteristic properties as metals and someproperties from the non-metals. They are found along the step-line which is locatedbetween the metals and the nonmetals
• Non-Metals are characteristically not lustrous, usually gases at room temperature, notmalleable, ductile or good conductors of electricity and heat. They are foundincreasingly from the 14th to 18th family.
FOUR FAMILIES:• Alkali Metals (IA), when in presence of water create a base and hydrogen gas
EX:2 Li(g) + H2O(l) → 2 LiOH(l) + H2(g)
• Alkaline Earth Metals (IIA), much like Alkali metals, create a base and hydrogen gaswhen in presence of water EX:
Ca + 2 H2O → H2(g) + Ca(OH2)(g)
• Halogens (VIIA), halogens have a high electronegativity and often have colorsattributed to them
• Inert Gases (VIIIA), Inert gases (a.k.a Noble Gases) have a full valence shell and tendnot to bond with other elements. These are, as the family name suggests, gases atroom temperature and are normally colorless unless electrically charged.
A.M.D.GULTIMATE SCIENCE REVIEW • JOSEPH SZYMBORSKI 12/25
Covalent Bonds
• Atoms that share pairs of electrons are said to form a covalent bond
•
Covalent bond usually only occur between two identical non-metals and two metals
The Cross-Over Rule
1. Write the symbols of the two elements placing the metal first
Mg Br
2. Write the valence of each element as a superscript
Mg2 Br 1
3. Cross over the valencesMg2 Br 1
4. Divide the valences by the G.C.F (if necessary, in this case, it isn't)
Mg1 Br 25. Drop any subscript that is 1
MgBr 2
BALANCING EQUATIONS:
• The most important concept to understand when balancing equations is tat the mass of the reactants is always equal to the mass of the products (Lavoisier's Law of Conservation of Mass)
A.M.D.GULTIMATE SCIENCE REVIEW • JOSEPH SZYMBORSKI 13/25
Steps for balancing an equation
1. Pick the most complex reactant or product2. Balance the elements contained in that substance on the other side of the equation3. Continue until all substances are balanced4. If there are any fractional coefficients, they must be eliminated by multiplaying every termby a constant
MOLE:
602,000,000,000,000,000,000,000 atoms in a mole (6.02 x 1023)
•The mole is the amount of substance that contains 6.02 x 10
23
particles of thatsubstance
• It can abbreviated as mol
• The number of moles of a given substance can be calculated with the formula
MASS OF SUBSTANCE (g) mn= ----------------------------------------- = --------
MOLAR MASS (g/mol) M
EX:12g of Carbon is 1 mol or Carbon44g of Carbon Dioxide is 1 mol of Carbon Dioxide4g of Helium is 1 mol of Helium40g of Argon is 1 mol of Argon18g of water is 1 mol of water 40g of Calcium is 1 mol of Calcium
STOICHIOMETRY:
• Are you stoic'd for stoichiometry?
• Stoichiometry is a method from which the quantities of substances required or produced from a given equation are defined.
EX:
How many grams of Aluminum Bromide will you need to create the following reaction if youhave 618.81 grams of Potassium Sulphate.
A.M.D.GULTIMATE SCIENCE REVIEW • JOSEPH SZYMBORSKI 24/25
ACIDS/BASES/SALTS:
• Acids contain at least one hydrogen atom that can be removed when the acid
dissolved in water, it therefore can donate H+ ion• Bases any substance that form hydroxide ions, OH-, in a water solution is a base. In
addition, a base is any substance that accepts H+ from acids. Most bases have ahydroxide ion.
• Salts neither start with H, nor end with OH: they start with the first part of the formulaof a base and end with the last part of the formula of an acid (because they are formedby the neutralization of an acid with a base)
ACID + BASE → WATER + SALT
H x + yOH →H2O + yx
INDICATORS:
• An indicator is an organic compound that changes color in an acid or a base
• Universal Indicators turn a different color at each pH level
• Most other indicators have one turning point and a total of three different colors
• A turning point is a usually small range in which the indicator changes color
• Both before and after the turning point, indicators usually have different colors
• However, some indicators only have two colors, having the same color for before andafter the turning point
pH:• Stands for “power of hydrogen”
• Scale of acidity or bascicity from 0 to 14
• Measure of the concentration of hydrogen ions within a solution
• Acids have a greater number of H+ ions than OH-
• Neutral (distilled water) contain an equal number of H+ and OH- ions
• Bases contains less H+ ions than OH- ions
• The higher the pH, the more basic it is
• The lower the pH, the more acidic it is
Concentration Formulas and Equations
• The [H+] concentration is equal to ten to the power of the negative pH of the substance
• [H+] = 10-pH
• The pH of a substance is equal to the negative log of the [H+] concentration
• pH = -log([H+])
• The sum of the [H+] concentration plus the [OH-] concentration is equal to ten to thepower of negative fourteen