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I. Chemistry Notes
A. Forms of Chemicals
1.Element- a substance composed of one kind of atom; a substance that cannot be broken down into other substances.
Examples include: Iron, sodium, hydrogen, neon, mercury, gold.
2.Compound- a substance that is a combination of two or more elements that cannot be separated by ordinary means. The elements in a compound lose some of their individual properties when they combine.
Examples of Compounds include: Water, Wood, Plastic, Salt, Iron oxide, paper.
3.Mixture- A substance made of two or more substances that can be separated by physical means; each member of the mixture keeps its individual properties.
Examples include: Salt water(solution); Sand and water; oil and vinegar; bronze(alloy)- a mixture of the metals copper and zinc; Stainless steel- a mixture of steel, chromium, and nickel; Chocolate milk; Fruit salad.
Elements, Compounds & Mixtures
II. The Periodic Table See Periodic Table provided by teacher on on-line source.
III. Specifics
A. Atoms- small units that that compose all matter;
1. Nucleus- center that contain a proton(+); neutron(no charge);
2. Electrons- negatively charged particles that orbit the nucleus and help to bond atoms;
3. Atoms are composed of smaller particles called quarks.
B. Bonds
1. Ionic bond- between atoms that give and take electrons to fill shells. Ex. Salt
2. Covalent bond- shared electrons between atoms; Water and diamond are the result of covalent bonds.
3. Metallic- wandering electrons that hold metals together; ex. Aluminum foil
C. Chemical Reactions:
1. Signs of chemical reactions: color, precipitate, smell, temperature change, bubbles
a. Not all reactions produce bubbles. Boiling is an example of a physical change; the bubbles do not show a chemical change. Alka-seltzer and water show a chemical reaction.
Ionic bond
Covalent bond
Diagram of the Atom
D. Chemical Reactions
1. Law of Conservation of Matter/Mass- mass can neither be created nor destroyed by ordinary means; matter is constant. It changes in form.
2. This law requires that chemical reactions must be mathematically balanced.
3. The 4 reactions:
a. Synthesis-
TYPES OF COMMON IONIC REACTION
SYNTHESIS REACTIONS
ALSO CALLED COMBINATION, CONSTRUCTION, OR COMPOSITION REACTIONS
The title of this section contains four names for the same type of reaction. Your text may use any of these. Chemtutor prefers the first of the names and will use “synthesis” where your text may use one of the other words. The hallmark of a synthesis reaction is a single product. A synthesis reaction might be symbolized by:
A + B AB
Two materials, elements or compounds, come together to make a single product. Some examples of synthesis reactions are: Hydrogen gas and oxygen gas burn to produce water.
2 H2 + O22 H2O and
sulfur trioxide reacts with water to make sulfuric acid.
H2O + SO3H2SO4
What would you see in a ‘test tube’ if you were witness to a synthesis reaction? You would see two different materials combine. A single new material appears.
b. Decomposition Reaction
Yes, a decomposition is a coming apart. A single reactant comes apart into two or more products, symbolized by:
XZ X + Z
Some examples of decomposition reactions are: potassium chlorate when heated comes apart into oxygen gas and potassium chloride
2 KClO3 2 KCl + 3 O2
and heating sodium bicarbonate releases water and carbon dioxide and sodium carbonate.
6 NaHCO33 Na2CO3 + 3 H2O + 3 CO2
In a “test tube” you would see a single material coming apart into more than one new material.
c. Single Replacement Reactions
Here is an example of a single replacement reaction: silver nitrate solution has a piece of copper placed into it. The solution begins to turn blue and the copper seems to disappear. Instead, a silvery-white material appears.
2 AgNO3 + Cu Cu(NO3)2 + 2 Ag
d. Double Replacement Reactions
AgNO3 + KCl AgCl(s) + KNO3
E. Catalysts vs Inhibitors
1. Catalysts- speed up chemical reactions without being lost in the reaction. Ex. Acid or salt used in the Hoffman Apparatus. Enzymes are catalysts found in living things.
2. Inhibitor- preservatives in food. They slow down chemical reactions.
F. Physical changes- changes in shape, size, or state. Examples:
Chemical changes below. Right click and open hyperlink below.
G. Chemical changes- molecules are rearranged; new products are produced. Examples.
Sour milk, yellow newspaper, baking a cake, rusting iron.
G. Balancing Equations
1. _____ H2 + _____ O2 ?_____ H2O
2. _____ N2 +_____ H2 ?_____ NH3
3. _____ S8 + _____ O2 ?_____ SO3
4. _____ N2 + _____ O2 ?_____ N2O
5. _____ HgO ?_____ Hg + _____ O2
6. _____ CO2 + _____ H2O ?_____ C6H12O6 + _____ O2
7. _____ Zn + _____ HCl ?_____ ZnCl2 + _____ H2
8. _____ SiCl4 + _____ H2O ?_____ H4SiO4 + _____ HCl
Open hyperlink to practice with balancing equations. The number of atoms on each side of the equation must be equal for each atom.
The left side is the reactant side. The right side is the product side. The number of atoms is indicated by the subscript. The coefficient is the number of molecules.
II. Isotopes- members of the same element having the same atomic number but a different mass. This is because they differ in the number of neutrons.
Hydrogen Isotopes
III. Periodic Table
A. Atomic Mass- the number of protons + neutrons.
B. Atomic Number- the number of protons or electrons in the atom.
C. To find the number of neutrons: Atomic Mass Subtract
- Atomic Number
______
Go to the following link for a great Periodic Table. Find the atomic numbers and mass numbers.
Exothermic and Endothermic Reactions or Examples
Heat given off….ExothermicEndothermic…..heat is absorbed away and material gets cold
III. Molecular Models
Examples of MoleculesCaffeine
The Diatomics
- Some elements exist as “twins” or two atoms bonded together.
- The Diatomic atoms are: Iodine, Bromine, Hydrogen, Nitrogen, Chlorine, Oxygen, Fluorine
- They are written as: I2 Br2 H2 N2 Cl2 O2 F2
- An example of Nitrogen would be:
Subcripts and Superscripts Subscript- the number written below and to the right of the element that tells the number of atoms of that element.
Because atoms are neither created nor destroyed in a reaction, a chemical equation must have an equal number of atoms of each element on each side of the arrow (i.e. the equation is said to be 'balanced').
Subscripts Must Never Be Changed. You can only change the coefficients.
Superscript- the number written above and to the right of the element that tells the charge and number of electrons that the element has to give or receive. These are the Cations and Anions. See the list provided by the teacher.
Here are some examples of cations and anions.
Aluminum / Al+3Ammonium / NH4+
Barium / Ba+2
Calcium / Ca+2
Chromium(II) / Cr+2 / Chromous
Chromium(III) / Cr+3 / Chromic
Copper(I) / Cu+ / Cuprous
Copper(II) / Cu+2 / Cupric
Iron(II) / Fe+2 / Ferrous
Iron(III) / Fe+3
You will need the following list of cations and anions to write chemical formulas.
These are the recommended cations an anions that you need in high school. Keep in mind that cations are + and anions are -
There are also polyatomic ions….multiple atoms bonded together with one charge for the entire group.
Cations + / Anions -H +1 / Cl -1
Li +1 / Br -1
Na +1 / O -2
K +1 / I -1
Rb +1 / F -1
Cs +1 / S -2 sulfide
Fr +1 / N -3
Be +2 / P -3
Mg +2
Ca +2
Sr +2
Ba+2
Ra+2
Ag+1
Ni+2
B+3
Al+3
Ga+3
In+3
Tl+3
C+4
Zn+2
Hg +1 and +2
Fe +2 and+3
Sn +2 and+4
Cu +1 and+2
Cr +2 and +3
Pb +2 and +4
Si +4
Polyatomic Cations and Anions Ammonium is the only + polyatomic below.
NH4+1 ammonium / ClO2 -1 chloriteCH3COO -1 acetate / CrO4 -2 chromate
CO3 -2 carbonate / Cr2O7 -2 dichromate
HCO3 -1 hydrogen carbonate / OH -1 hydroxide
ClO3 -1 chlorate / NO3-1nitrate
NO2 -1 nitrite / PO4-3 phosphate
SO4-2 sulfate / SO3-2 sulfite
AsO4-3 arsenate / O2-2 peroxide
SiO3-2 silicate / MnO4-1 permanganate
ClO4-1 perchlorate / C2O4-2oxalate
The Atom
Neutron-particle found in the nucleus with NO charge and a mass of 1 A.M.U.
Proton- particle found in the nucleus with a Positive charge and a mass of 1 A.M.U.
Electron- particle found orbiting the nucleus in cloud formation with a mass of .00054 A.M.U. An A.M.U. =
10.Atomic Mass Unit or 1.66 x 10 -24 grams.
Atoms bond to form molecules. Bonds include: metallic; ionic; and covalent.
11. Ion- charged atom
12. Physical change- changing state; solids, liquids, and gases.
13. Chemical change- change in molecular arrangement; the original material changes to a new product.
14. Product- material produced at the end of the chemical equation.
15. Reactants- materials that combine to produce products in a chemical reaction.
16. Exothermic- a chemical reaction that results in heat loss. Ex. Adding strong acid to metal. Rusting iron. Adding calcium chloride to water is an exothermic reaction.
17. Endothermic- a chemical reaction in which heat is taken in. Adding heat to bake a cake; Adding ammonia to barium sulfate produces and endothermic reaction.
18. Sublimation- changing directly from a solid to a gas without passing through the liquid state.
19. Condensation- changing from a gas to a liquid by cooling.
20. Evaporation- changing from a liquid to a gas.
21. AMU= atomic mass unit.
22. Law of Conservation of Mass and Matter- Mass and matter are neither created nor destroyed; the sum total of mass/matter in the universe is constant.
23. Law of Conservation of Energy- Energy is conserved; the sum total of energy is constant and is changed from one form to another.
24. Energy- the ability to do work.
25. Energy forms include: Electrical, Chemical, Heat, Light, Sound, Nuclear, Mechanical
26. Valence electrons or Valence number=number of electrons in the outermost shell of an atom.
27. Molecule- the smallest chunk of matter that still acts like that matter. Examples; water, iodine, rust, chalk.
28. Dmitri Mendeleev- “father” of the Periodic Table.
29. John Dalton- “father” of the Atomic Theory. “billiard ball model.”
30. Niels Bohr- “father” of the modern Atomic Theory.
31. Ernest Rutherford- famous gold foil experiment in which he proved a small, positively charged nucleus and that the atom is mostly empty space.
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