AP Chemistry Topic Review

  1. Know the following :
  1. Know Symbols for Elements (see S1)
  2. Rules for Significant Figures (see S2)
  3. Diatomic Elements (see S3)
  4. Common Polyatomic Ions and Their Charges(S4)
  5. Strong Acids and Basesand Strong Electrolytes(S5)
  6. Prefixes for Molecular Nomenclature (S6)
  7. Metric System Prefixes (S7)
  8. Base Units of the Metric System (S8)
  9. Solubility Rules (S9)
  10. Periodic Trends (S10)
  11. Basic pH Information (S11)
  12. Acid Nomenclature (S 12)
  13. Electron Configurations Using Periodic Table (S13)
  14. Safety Rules (S14)
  15. Name and Proper Use of Laboratory Equipment. (S15)
  1. You should be able to write formulas and/or name compounds for:
  2. Binary Ionic Compounds.
  3. Binary Molecular Compounds
  4. Ternary Ionic Compounds
  5. Acids and Bases
  6. Some hydrocarbons
  1. Be able to complete equations for reactions involving:
  2. Combination
  3. Decomposition
  4. Single-replacement
  5. Metathesis (precipitation)
  6. Acid-base (neutralization)
  7. Combustion
  8. Net ionic and Redox reactions
  1. Use dimensional analysis to solve problems/stoichiometric calculations using balanced equations.

S1.The Elements

Know the name and symbol of elements. Know family names or groups.

S2. Significant Figures

Rules for counting significant figures are summarized below.

  1. Zeros within a number are always significant. Both 4308 and 40.05 contain four significant figures.
  2. Zeros that do nothing but set the decimal point are not significant. Thus, 470,000 has two significant figures.
  3. Trailing zeros that aren't needed to hold the decimal point are significant. For example, 4.00 has three significant figures.
  4. If you are not sure whether a digit is significant, assume that it isn't. For example, if the directions for an experiment read: "Add the sample to 400 mL of water," assume the volume of water is known to one significant figure.

Significant Figures continued:

When measurements are added or subtracted, the answer can contain no more decimal places than the least accurate measurement.

150.0 g H2O
+ 0.507 g salt
150.5 g solution

When measurements are multiplied or divided, the answer can contain no more significant figures than the least accurate measurement.

Example: To illustrate this rule, let's calculate the cost of the copper in an old penny that is pure copper. Let's assume that the penny has a mass of 2.531 grams, that it is essentially pure copper, and that the price of copper is 67 cents per pound. We can start by from grams to pounds.

We then use the price of a pound of copper to calculate the cost of the copper metal.

There are four significant figures in both the mass of the penny (2.531) and the number of grams in a pound (453.6). But there are only two significant figures in the price of copper, so the final answer can only have two significant figures.

Rounding Off

When the answer to a calculation contains too many significant figures, it must be rounded off.

There are 10 digits that can occur in the last decimal place in a calculation. One way of rounding off involves underestimating the answer for five of these digits (0, 1, 2, 3, and 4) and overestimating the answer for the other five (5, 6, 7, 8, and 9). This approach to rounding off is summarized as follows.

If the digit is smaller than 5, drop this digit and leave the remaining number unchanged. Thus, 1.684 becomes 1.68.

If the digit is 5 or larger, drop this digit and add 1 to the preceding digit. Thus, 1.247 becomes 1.25.

S3. Know the 7 Diatomic Elements

Hydrogen (H2); Nitrogen (N2); Oxygen (O2); Fluorine (F2); Chlorine (Cl2); Bromine (Br2); Iodine (I2)

S4. Know the name, symbol for, and charge of Common Polyatomic Ions and TheirCharges

The following polyatomic ions are arranged in related groups according,mostly, to the periodic table. In MEMORIZING these ions, look for similarities with in families. Thesuffix X–ate is the common ion in a group of similar ions, X–ite means one oxygen less, hypo-x-itetwo oxygens less, per-X-ate one oxygen more. The prefix thio- usually means an oxygen atom has beenreplaced with a sulfur atom (not always but usually).

S5. Strong Acids and Bases

The 7 Strong Acids

HCl
hydrochloric acid / HNO3
nitric acid / H2SO4
sulfuric acid
HBr
hydrobromic acid
HI
hydroiodic acid / HClO3
chloric acid / HClO4
perchloric acid

The 8 Strong Bases

LiOH / lithium hydroxide
NaOH / sodium hydroxide
KOH / potassium hydroxide / Ca(OH)2 / calcium hydroxide
RbOH / rubidium hydroxide / Sr(OH)2 / strontium hydroxide
CsOH / cesium hydroxide / Ba(OH)2 / barium hydroxide

Strong Electrolytes: Strong electrolytes consist of substances that ionize completely (approximately 100%) in water. These substances are strong acids, strong bases, and soluble ionic salts.

Weak Electrolytes: Substances that ionize approximately 1-5% in water form weak electrolytes. These substances are weak acids, weak bases, and slightly soluble ionic salts.

Non-Electrolytes: Substances that dissolve in water but are considered polar covalent, like table sugar and some alcohols, are considered non-electrolytes.

S6. Prefixes for Molecular Compounds

This is a usual type of binary compound composed of two nonmetals. Such a compound is named by using a Greek prefix designating the number of atoms for the elements in the formula. Note that the Greek prefix "mono-" is not used with the first element, just the second. Also, end the name of the second element in "ide".

Greek Prefixes / Number
mono- / 1
di- / 2
tri- / 3
tetra- / 4
penta- / 5
hexa- / 6
hepta- / 7
octa- / 8
nona- / 9
deca- / 10
hendeka- / 11
dodeka- / 12

S7. Metric System Prefixes

To help the SI units apply to a wide range of phenomena, the 19th General Conference on Weights and Measures in 1991 extended the list of metric prefixes so that it reaches from yotta- at 1024 (one septillion) to yocto- at 10-24 (one septillionth). Here are the metric prefixes, with their numerical equivalents stated in the American system for naming large numbers:

yotta- (Y-) / 1024 / 1 septillion
zetta- (Z-) / 1021 / 1 sextillion
exa- (E-) / 1018 / 1 quintillion
peta- (P-) / 1015 / 1 quadrillion
tera- (T-) / 1012 / 1 trillion
giga- (G-) / 109 / 1 billion
mega- (M-) / 106 / 1 million
kilo- (k-) / 103 / 1 thousand
hecto- (h-) / 102 / 1 hundred
deka- (da-)** / 10 / 1 ten
deci- (d-) / 10-1 / 1 tenth
centi- (c-) / 10-2 / 1 hundredth
milli- (m-) / 10-3 / 1 thousandth
micro- (µ-) / 10-6 / 1 millionth
nano- (n-) / 10-9 / 1 billionth
pico- (p-) / 10-12 / 1 trillionth
femto- (f-) / 10-15 / 1 quadrillionth
atto- (a-) / 10-18 / 1 quintillionth
zepto- (z-) / 10-21 / 1 sextillionth
yocto- (y-) / 10-24 / 1 septillionth

S8. Base Units of the Metric System

Know the following 8 BASE UNITS:

BASE UNIT - meter (m) - LENGTH

Up until 1983 the meter was defined as 1,650,763.73 wavelengths in a vacuum of the orange-red line of the spectrum of krypton-86. And since then it is determined to be the distance traveled by light in a vacuum in 1/299,792,45 of a second.

BASE UNIT - second (s) – TIME

The second is defined as the duration of 9,192,631,770 cycles of the radiation associated with a specified transition of the cesium-133 atom.

BASE UNIT - kilogram (kg) – MASS

The standard for the kilogram is a cylinder of platinum-iridium alloy kept by the International Bureau of Weights and Measures in Paris. A duplicate at the National Bureau of Standards serves as the mass standard for the United States. The kilogram is the only base unit defined by a physical object.

BASE UNIT - Kelvin (K) and °Celsius (°C) - TEMPERATURE

The Kelvin is defined as the fraction 1/273.16 of the thermodynamic temperature of the triple point of water; that is, the point at which water forms an interface of solid, liquid and vapor. This is defined as 0.01 °C on the Celsius scale and 32.02 °F on the Fahrenheit scale. The temperature zero K (Kelvin) is called "absolute zero".

BASE UNIT - ampere (A) - ELECTRIC CURRENT

The ampere is defined as that current that, if maintained in each of two long parallel wires separated by one meter in free space, would produce a force between the two wires (due to their magnetic fields) of 2 x 10-7 N (newton) for each meter of length. (a Newton is the unit of force that when applied to one kilogram mass would experience an acceleration of one meter per second, per second).

BASEUNIT - candela (cd) - LUMINOUS INTENSITY

The candela is defined as the luminous intensity of 1/600,000 of a square meter of a cavity at the temperature of freezing platinum (2,042 K).

BASE UNIT - mole - (mol) AMOUNT OF SUBSTANCE

The mole is the amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12.

BASE UNIT – liter - (L) VOLUME OF A SUBSTANCE (THIS IS A DERIVED UNIT)

S9. Solubility Rules

Soluble Compounds

1. All compounds of the alkali metals (Group 1) are soluble.

2. All salts containing NH4+, NO3-, ClO4-, ClO3-, and C2H3O2- are soluble.

3. All chlorides (Cl-), bromides (Br-), and iodides (I-) are soluble, except those of Ag+, Pb2+, and Hg22+.

4. All sulfates (SO42-) are soluble, except those of Ag+, Pb2+, Ca2+, Sr2+, Hg22+, and Ba2+.

Insoluble Compounds

5. All hydroxides (OH-) are insoluble except those of Group 1, NH4+ and Ca2+, Sr2+, and Ba2+

6. All salts containing PO43-, CO32-, SO32-, and S2- are insoluble, except those of Group 1 and NH4+.

S10. Periodic Trends

Atomic radius

The atomic radius is the distance from the atomic nucleus to the outermost stable electron orbital in an atom that is at equilibrium. The atomic radius tends to decrease as one progresses across a period because the effective nuclear charge increases, thereby attracting the orbiting electrons and lessening the radius. The atomic radius usually increases while going down a group due to the addition of a new energy level (shell). However, diagonally, the number of protons has a larger effect than the sizeable radius. For example, lithium (145 pm) has a smaller atomic radius than magnesium (150 pm). Atomic radii decrease left to right across a period, and also increase top to bottom down a group.

Ionization potential

The ionization potential (or the ionization energy) is the minimum energy required to remove one electron from each atom in a mole of atoms in the gaseous state. The first ionization energy is the energy required to remove one, the nth ionization energy is the energy required to remove the atom's nth electron, after the (n−1) electrons before it have been removed. Trend-wise, ionization potentials tend to increase while one progresses across a period because the greater number of protons (higher nuclear charge) attract the orbiting electrons more strongly, thereby increasing the energy required toremove one of the electrons.There will be an increase of ionization energy from left to right of a given period and a decrease from top to bottom.

Electron affinity

The electron affinity of an atom can be described either as the energy gained by an atom when an electron is added to it, or conversely as the energy required to detach an electron from a singly-charged anion. As one progresses from left to right across a period, the electron affinity will increase, due to the larger attraction from the nucleus, and the atom "wanting" the electron more as it reaches maximum stability. Down a group, the electron affinity decreases because of a large increase in the atomic radius, electron-electron repulsion and the shielding effect of inner electrons against the valence electrons of the atom.

Electronegativity

Electronegativity is a measure of the ability of an atom or molecule to attract pairs of electrons in the context of a chemical bond. The type of bond formed is largely determined by the difference in electronegativity between the atoms involved, using the Pauling scale. Trend-wise, as one moves from left to right across a period in the periodic table, the electronegativity increases due to the stronger attraction that the atoms obtain as the nuclear charge increases. Moving down a group, the electronegativity decreases due to the longer distance between the nucleus and the valence electron shell, thereby decreasing the attraction, making the atom have less of an attraction for electrons or protons.

Metallic character

Metallic character refers to the chemical properties associated with elements classified as metals. These properties, which arise from the element's ability to lose electrons, are: the displacement of hydrogen from dilute acids; the formation of basic oxides; the formation of ionic chlorides; and their reduction reaction, as in the thermite process. As one moves across a period from left to right in the periodic table, the metallic character decreases, as the atoms are more likely to gain electrons to fill their valence shell rather than to lose them to remove the shell. Down a group, the metallic character increases, due to the lesser attraction from the nucleus to the valence electrons (in turn due to the atomic radius), thereby allowing easier loss of the electrons or protons.

The following diagram represents the trend in the periodic table for atomic size (atomic radius in picometers).

The following represents the trend in ionization energy.

The following represents trends between Metals, Metalloids and Non-Metals

S11. Basic pH Information

S12. Acid Nomenclature

Naming Acids

Acids-For simplicity, the acids that we will be concerned with naming are really just a special class of ionic compounds where the cation is always H+. So if the formula has hydrogen written first, then this usually indicates that the hydrogen is an H+cation and that the compound is an acid. When dissolved in water, acids produce H+ ions (also called protons, since removing the single electron from a neutral hydrogen atom leaves behind one proton).

Rules for Naming Acids that Do Not Contain Oxygen in the Anion:

  • Since all these acids have the same cation, H+, we don't need to name the cation.
  • The acid name comes from the root name of the anion name.
  • The prefix hydro- and the suffix -ic are then added to the root name of the anion.

HCl, which contains the anion chloride, is called hydrochloric acid.

HCN, which contains the anion cyanide, is called hydrocyanic acid.

Rules for Naming Oxyacids (anion contains the element oxygen):

  • Since all these acids have the same cation, H+, we don't need to name the cation.
  • The acid name comes from the root name of the oxyanion name or the central element of the oxyanion.
  • Suffixes are used based on the ending of the original name of the oxyanion. If the name of the polyatomic anion ended with -ate, change it to -ic for the acid and if it ended with -ite, change it to -ous in the acid.

HNO3, which contains the polyatomic ion nitrate, is called nitric acid.

HNO2, which contains the polyatomic ion nitrite, is called nitrous acid.

S13. Electron Configurations Using the Periodic Table

The primary determinant of an element's chemical properties is its electron configuration, particularly the valence shell electrons. For instance, any atoms with four valence electrons occupying p orbitals will exhibit some similarity. The type of orbital in which the atom's outermost electrons reside determines the "block" to which it belongs. The number of valence shell electrons determines the family, or group, to which the element belongs.
The total number of electron shells an atom has determines the period to which it belongs. Each shell is divided into different subshells, which as atomic number increases are filled in roughly this order (the Aufbau principle):

Subshell: / S / G / F / D / P
Period
1 / 1s
2 / 2s / 2p
3 / 3s / 3p
4 / 4s / 3d / 4p
5 / 5s / 4d / 5p
6 / 6s / 4f / 5d / 6p
7 / 7s / 5f / 6d / 7p
8 / 8s / 5g / 6f / 7d / 8p

Hence, the structure of the table. Since the outermost electrons determine chemical properties, those with the same number of valence electrons are grouped together.

S14. Laboratory Safety Rules

Using Bunsen Burners Safely

• Remove all flammable and combustiblematerials from the lab bench and surrounding work area when Bunsenburners will be used. Do NOT use aBunsen burner in any lab when workingwith flammable liquids or solvents.

• Review the basic construction of aBunsen burner and inspect the burner,attached tubing, and gas valve beforeuse. Check for holes or cracks in thetubing and replace the tubing if necessary.

• Use only heat-resistant, borosilicateglassware when using a Bunsen burner.Check the glassware for scratches, nicksor cracks before use and discard defectiveglassware—cracked glassware mayshatter without warning when heated.

• Wear chemical-splash goggles wheneverworking with chemicals, heat or glassware in the science lab. Tie back long hairwhen working with a Bunsen burner, anddo not wear loose, long-sleeved clothing.Never reach over an exposed flame!

• Never leave a lit burner unattended. Always turn off the gas at the gas source when finished using a Bunsen burner.

• To reduce heat stress, allow hot glassware or equipment to cool slowly before moving or removing the object. Remember that hot objects remain HOT for a very long time—use tongs and handle with care!

Using Hot Plates Safely

Hot plates offer convenience and important safety benefits for use in preparing hot water baths for mild to moderate heating.

• Use only heat-resistant, borosilicate glassware, and check for cracks before heating on a hot plate. Do not place thick-walled glassware, such as filter flasks, or soft-glass bottles and jars on a hot plate. The hot plate surface should be larger than the vessel being heated.

• Do not use the hot plate in the presence of flammable or combustible materials. Fire or explosion may result—the device contains components that may ignite such material.

• Place boiling stones in liquids being heated to facilitate even heating and boiling. Do not evaporate all of the solvent or otherwise heat a mixture to dryness on a hot plate—the glass may crack unexpectedly when heated directly on a hot plate.

• Use a medium to medium-high setting of the hot plate to heat most liquids, including water. Do not use the high setting to heat low-boiling liquids. The hot plate surface can reach a maximum temperature of 540 °C.