SAT Chemistry Subject Test
Percent Dissociation
% dissociation = (Moles/liter that dissociate)/(original concentration) x 100
Molarity
(Abbreviated M) The number of moles of a substance dissolved in 1 liter of solution
Molality
(Abbreviated m) The number of moles of the solute dissolved in 1,000 grams of solvent
Amorphous Solids
(Literally, "solids without form") Characterized by a random structure, with little if any long-range order
Diatomic Elements
*H*ydrogen *O*xygen *N*itrogen *Cl*: Chlorine *Br*omine *I*odine *F*luorine
LEO the lion says GER
*L*oss of *E*lectrons *O*xidation *G*ain of *E*lectrons *R*eduction
Types of Solutes and Relationships of Type to Solubility
*Like dissolves like* Generally speaking, solutes are most likely to dissolve in solvents with similar characteristics; that is, ionic and polar solutes dissolve in polar solvents, and nonpolar solutes dissolve in nonpolar solvents
Sublimation
*Solid → Gas* When heated at certain pressures, some solids vaporize directly without passing through the liquid phase.
Periodic Table Trends
- Acid-forming properties increase from left to right on the table - Base-forming properties are high on the left side and decrease to the right - The atomic radii of elements decrease from left to right across a period - First ionization energies increase from left to right across a period - Metallic properties are greatest on the left side of the table and decrease to the right - Nonmetallic properties are greatest on the right side of the table and decrease to the left
Arrhenius Theory of Acids and Bases
- Acids contribute H⁺ (H₃O⁺) to solution - Bases contribute OH⁻ to solution
Bronsted-Lowry Acid Base Theory
- Acids donate H⁺ to solution - Bases accept H⁺ from solution (making OH⁻) - The original acid gives up its proton to become a *conjugate base*. After losing its proton, the remaining ion is capable of gaining a proton, thus qualifying as a base - The original base accept a proton, so it now is classified as a *conjugate acid* since it can release this newly acquired proton and thus behave like an acid *The stronger an acid is, the weaker its conjugate base; the stronger a base is, the weaker its conjugate acid*
Lewis Acids Base Theory (Kf)
- Any time there is a formation reaction when there is a Kf - A Lewis Acid accepts a pair of electrons - A Lewis Base donates a pair of electrons *Look for things with nitrogen, negative ions, and things with high electronegativity, electron rich, lone pairs, electron deficient (positive ions), Be, B*
Allotropic Forms of Carbon
- Diamond - Graphite - Amorphous - Fullerenes
Percent Yield
- In chemical reactions you calculate the Theoretical Yield = MAX based on the given amounts of reactants. In reality the amount that you actually obtain will be different from the theoretical yield (usually less... but not always). This is called the Experimental or Actual Yield. - Percent Yield = (Experimental Yield/Theoretical Yield) * 100 - Percent Yield is a "comment" on your lab technique
London Dispersion Forces
- Occur between all molecules - These very weak attractions occur because of the random motions of electrons within molecules. At a given moment, a nonpolar molecule might have more electrons on one side than on the other, giving it an instantaneous polarity. For that fleeting instant, the molecule will act as a very weak dipole. - *Since London dispersion forces depend on the random motions of electrons, molecules with more electrons will experience greater London dispersion forces. London dispersion forces can be very strong with a molecule with a lot of electrons (elements with high molar masses).*
Dipole-Dipole Forces
- Occur between polar molecules - The positive end of one polar molecule is attracted to the negative end of another polar molecule
Transition metals that form only one type of cation
- Silver Ag¹⁺ - Cadmium Cd²⁺ - Zinc Zn²⁺
Hydrogen Bonds
- Special dipole-dipole forces - In a hydrogen bond, the positively charged hydrogen end of a molecule is attracted to the negatively charged end of another molecule containing an extreme electronegative element (fluorine, oxygen, or nitrogen - F, O, N)
Le Chatelier's Principle
- When an equilibrium is subjected to a stress, the equilibrium shifts to lessen the stress - Same side = different - Different side = same
How to Calculate Leftover Excess Reactant
- When the Percent Yield is 100%, take the amount of product and subtract the limiting reactant - When the Percent Yield is less than 100%, take the original amount of excess reactant and subtract the amount of used excess reactant which you can find by taking the amount of the limiting reactant and converting to moles of the excess reactant using the molar ratio
*THE CHART*
- When ΔH is positive, ΔS is negative, and ΔG is positive, the reaction is non-spontaneous at all temperatures - When ΔH is negative, ΔS is positive, and ΔG is negative, the reaction is spontaneous at all temperatures - When ΔH is positive, ΔS is positive, and ΔG is positive or negative, the reaction is spontaneous at all high temperatures - When ΔH is negative, ΔS is negative, and ΔG is positive or negative, the reaction is spontaneous at low temperatures
Naming Salts formed from Acids
-ic acids form -ate salts -ous acids form -ite salts hydro-(stem)-ic acids form -ide salts
pH
-log[H₃O⁺] pH range of 1 to 6 is acidic pH range of 8 to 14 is basic
Absolute Zero
0 K or -273.15° C
calories to joules
1 calorie equals 4.18 joules
Milliliter to Centimeter Conversion
1 mL = 1 cm³
How to identify carbonate (CO₃⁻)
1. Add HCl acid; pass released gas through limewater - Result: White, cloudy precipitate forms
How to identify sulfide (S²⁻)
1. Add HCl and test gas released with lead acetate paper - Result: Gas, with rotten egg odor, turns paper brown-black
How to identify acetate (C₂H₃O₂⁻)
1. Add concentrated H₂SO₄ and warm gently - Result: Odor of vinegar released
How to identify chloride (Cl⁻)
1. Add silver nitrate solution - Result: White precipitate forms 2. Then add nitric acid, later followed by ammonium hydroxide - Result: Precipitate insoluble in HNO₃ but dissolves in NH₄OH
How to identify sulfate (SO₄⁻)
1. Add solution of BaCl₂, then HCl - Result: White precipitate forms; insoluble in HCl
How to identify ferrous (Fe²⁺)
1. Add solution of potassium ferricyanide, K₃Fe(CN)₆ - Result: Dark blue precipitate forms (Turnball's blue)
How to identify ferric (Fe³⁺)
1. Add solution of potassium ferrocyanide, K₄Fe(CN)₆ - Result: Dark blue precipitate forms (Prussian blue)
How to identify ammonium (NH₄⁺)
1. Add strong base (NaOH); heat gently - Result: Odor of ammonia
Significant Digits Rules
1. All digits other than zeros are significant 2. Zeros between nonzero digits are significant 3. Final zeros to the right of the decimal point are significant 4. In numbers smaller than 1, zeros to the left or directly to the right of the decimal point are not significant
Dalton's Model of the Atom
1. All matter is made up of very small, discrete particles called atoms 2. All atoms of an element are alike in weight is different from that of any other kind of atom 3. Atoms cannot be subdivided, created, or destroyed 4. Atoms of different elements combine in simple whole-number ratios to form chemical compounds 5. In chemical reactions, atoms are combined, separated, or rearranged
How to identify hydrogen (H₂)
1. Allow it to mix with some air, then ignite - Result: Gas explodes 2. Burn it - trap product - Result: Burns with blue flame - product H₂O turns cobalt chloride paper from blue to pink
How to solve for pH by hand
1. Arrange the concentration of the acid into scientific notation 2. Use the exponent to approximate the answer. The answer will be between the exponent and the integer directly below it.
Atomic and Ionic Radii Trend
1. Atomic radii decrease from left to right across a period in the Periodic Table (until the noble gases) *Explanation:* Since the number of electrons in the outer principal energy level increases as you go from left to right in each period, the corresponding increase in nuclear charge because of the additional protons pulls the electrons more tightly around the nucleus. 2. Atomic radii increase from top to bottom in a group or family *Explanation:* For a group of elements, the atoms of each successive member have another outer principal energy level in the electron configuration, and the electrons there are held less tightly by the nucleus. This is so because of their increased distance from the nuclear positive charge and the shielding of this positive charge by all the core electrons.
Base Properties
1. Bases are conductors of electricity in an aqueous solution 2. Bases cause a color change in indicators 3. Bases react with acids to neutralize each other and form a salt and water 4. Bases react with fats to form a class of compounds called soaps 5. Aqueous solutions of bases feel slippery, and the stronger bases are very caustic to the skin
How to identify carbon monoxide (CO)
1. Burn it and pass product through limewater, Ca(OH)₂ - Result: White precipitate forms, CaCO₃
How to predict if a precipitate will form
1. Calculate the Ksp of the reaction 2. Compare to the known value of Ksp at standard conditions. If the Ksp from step 1 is greater than the known Ksp, the concentrations cannot exist, and the ions will combine to form a solid precipitate. Only enough ions will remain to make the product of the respective ion concentrations equal to the known Ksp
Solubility Rules
1. Compounds with an alkali metal cation (Na⁺¹, Li⁺¹, K⁺¹, etc.) or an ammonium cation (NH₄⁺¹) are always soluble 2. Compounds with a nitrate (NO₃⁻¹) anion are always soluble 3. All chlorides are soluble *except those of silver, mercury (I) Hg₂²⁺, and lead* 4. All sulfates are soluble *except those of lead, barium, strontium, and calcium* 5. The normal carbonates, phosphates, silicates, and sulfides are insoluble *except those of sodium, potassium, and ammonium* 6. All hydroxides are insoluble *except those of sodium, potassium, ammonium, calcium, barium, and strontium (The strong bases)*
The Ten Commandments of Lab Safety
1. Dress appropriately for the lab. Wear safety googles and a lab apron or coat. Tie back long hair. Do not wear open-toed shoes. 2. Know what safety equipment is available and how to use it. This includes the eyewash fountain, fire blanket, fire extinguisher, and emergency shower. 3. Know the dangers of the chemicals in use, and read labels carefully. Do not taste or sniff chemicals. 4. Dispose of chemicals according to instructions. Use designated disposal sites, and follow the rules. Never return unneeded chemicals to the original containers. 5. Always add acids and bases to water slowly to avoid splattering. This is especially important when using strong acids and bases that can generate significant heat, form steam, and splash out of the container. 6. Never point heating test tubes at yourself or others. Be aware of reactions that are occurring so that you can remove them from the heat if necessary before they "shoot" out of the test tube. 7. Do not pipette anything by mouth! Never use your mouth as a suction pump, not even at home with toxic or flammable liquids. 8. Use the fume hood when dealing with toxic fumes! If you can smell them, you are exposing yourself to a dose that can harm you. 9. Do not eat or drink in the lab! It is too easy to take in some dangerous substance accidentally. 10. Follow all directions. Never haphazardly mix chemicals. Pay attention to the order in which chemicals are to be added to each other, and do not deviate!
6 Strong Acids
1. HCl - Hydrochloric Acid 2. HBr - Hydrobromic Acid 3. HI - Hydriodic Acid 4. HNO₃ - Nitric Acid 5. HClO₄ - Perchloric Acid 6. H₂SO₄ - Sulfuric Acid
Properties of Ionic Substances
1. In the solid phase at room temperature, they do not conduct appreciable electric current 2. In the liquid phase, they are relatively good conductors of electric current. The conductivity of ionic substances is much smaller than that of metallic substances. 3. They have relatively high melting and boiling points. There is a wide variation in the properties of different ionic compounds 4. They have relatively low volatilities and low vapor pressures. In other words, they do not vaporize readily at room temperature 5. They are brittle and easily broken when stress is exerted on them 6. Those that are soluble in water form electrolytic solutions that are good conductors of electricity. There is, however, a wide range in the solubilities of ionic compounds
How to identify oxygen (O₂)
1. Insert glowing splint - Result: Bursts into flame 2. Add nitric oxide gas - Result: Turns reddish brown
Chemical Properties of Hydrogen
1. It burns in air or in oxygen, giving off large amounts of heat. Its high heat of combustion makes it a good fuel 2. It does not support ordinary combustion 3. It is a good reducing agent in that it withdraws oxygen from many hot metal oxides
Physical Properties of Hydrogen
1. It is ordinarily a gas; colorless, odorless, tasteless when pure 2. It weights 0.9 gram per liter at 0°C and 1 atmosphere pressure. This is 1/14 as dense as air 3. It is slightly soluble in water 4. It becomes a liquid at a temperature of -240°C and a pressure of 13 atmospheres. 5. It diffuses (moves from place to place in gases) more rapidly than any other gas
How to find the limiting reactant and the theoretical yield
1. Make sure the equation is balanced 2. Calculate the mass of the appropriate product based on each amount of the reactants given 3. The smaller product amount (Theoretical Yield) points to the limiting reactant
Kinetic-Molecular Theory
1. Matter in all its forms (solid, liquid, and gas) is composed of extremely small particles. In many cases, these are called molecules. The space occupied by the gas particles themselves is ignored in comparison with the volume of the space in which they are contained. 2. The particles of matter are in constant motion. In solids, this motion is restricted to a small space. In liquids, the particles have a more random pattern but still are restricted to a kind of rolling over one another. In a gas, the particles are in continuous, random, straight-line motion 3. When these particles collide with each other or with the walls of the container, there is no loss of energy
6 Strong Bases
1. NaOH - Sodium Hydroxide 2. KOH - Potassium Hydroxide 3. LiOH - Lithium Hydroxide 4. Ca(OH)₂ - Calcium Hydroxide 5. Ba(OH)₂ - Barium Hydroxide 6. Sr(OH)₂ - Strontium Hydroxide
Properties of Molecular Crystals and Liquids
1. Neither the liquids nor solids conduct electric current appreciably 2. Many exist as gases at room temperature and atmospheric pressure, and many solids and liquids are relatively volatile 3. The melting points of solid crystals are relatively low 4. The boiling points of the liquids are relatively low 5. The solids are generally soft and have a waxy consistency 6. A large amount of energy is often required to decompose the substance chemically into simpler substances
How to identify carbon dioxide (CO₂)
1. Pass through limewater, Ca(OH)₂ - Result: White precipitate forms, CaCO₃
How to identify hydrogen chloride (HCl)
1. Smell cautiously - Result: Choking odor 2. Exhale over the gas - Result: Vapor fumes form 3. Dissolve in water and test with litmus - Result: Blue litmus turns red 4. Add AgNO₃ to the solution - Result: White precipitate forms
How to identify hydrogen sulfide (H₂S)
1. Smell cautiously - Result: Rotten egg odor 2. Test with moist lead acetate paper - Result: Turns brown-black (PbS)
How to identify ammonia (NH₃)
1. Smell cautiously - Result: Sharp odor 2. Test with litmus - Result: Red litmus turns blue 3. Expose to HCl fumes - Result: White fumes form, NH₄Cl
How to identify hydrogen (H⁺)
1. Test with blue litmus paper - Result: Turns red
How to identify hydroxide (OH⁻)
1. Test with red litmus paper - Result: Turns blue
Factors that affect the rate of reactions
1. The nature of the reactants - The rates of chemical reactions is affected by the nature of the bonds in the reacting substances - Reactions between ions in an aqueous solution may take place in a fraction of a second - In reactions where many covalent bonds must be broken, reaction usually takes place slowly at room temperatures 2. The surface area exposed - Greater surface area = faster reaction rate 3. The concentrations - Greater concentration of reactants = faster reaction rate - If more molecules or ions of the reactant are in the reaction area, then there is a greater chance that more reactions will occur 4. The temperature - As the temperature increases, the average kinetic energy of the particles involved increases. As a result, the particles move faster and have a greater probability of hitting other reactant particles. Because the particles have more energy, they can cause an effective collision, resulting in the chemical reaction that forms the product substance 5. The presence of a catalyst - The catalyst provides an alternative pathway by which the reaction can proceed and in which the activation energy is lower. It thus increases the rate at which the reaction comes to completion or equilibrium. Generally, the term is used for a substance that increases reaction rate (a positive catalyst). Some reactions can be slowed down by negative catalysts
Acid Properties
1. Water (aqueous) solutions of acids conduct electricity 2. Acids will react with metals that are more active than hydrogen ions to liberate hydrogen 3. Acids have the ability to change the color of indicators 4. Acids react with bases so that the properties of both are lost to form water and a salt (neutralization) 5. Acids react with carbonates to release carbon dioxide
Prefixes for Covalent Compounds
1: Mono- 2: Di- 3: Tri- 4: Tetra- 5: Penta- 6: Hexa- 7: Hepta- 8: Octa- 9: Nona- 10: Deca-
What does Kw equal at 25°C?
1x10⁻¹⁴
Composition of Water
2 parts hydrogen: 1 part oxygen Water can be made by mixing hydrogen and oxygen in a eudiometer over mercury and passing an igniting spark through the mixture
Joules to Kilocalories
4.18 x 10³ joules (J) equals 1 kilocalorie (kcal)
D Orbitals
5 orientations and can hold 2 electrons each, making a total of 10
Earth's Atmosphere
78% Nitrogen, 21% Oxygen, 0.9% Argon, 0.03% Carbon Dioxide, varying amounts of water vapor, and trace amounts of hydrogen, ozone, methane, carbon monoxide, helium, neon, krypton, and xenon.
Composition of Air by Volume
78% Nitrogen, 21% Oxygen, 1% Argon, small amounts of carbon dioxide, water vapor, and trace gases
Lewis Structure
A Lewis structure shows the atomic symbol to represent the nucleus and inner shell electrons. It shows dots to represent valence electrons
Sigma Bond
A bond between s orbitals, or an s orbital and another orbital such as a p orbital
Diamond
A close-packed crystal structure that gives it its property of extreme hardness. In it, each carbon is bonded to four other carbons in a tetrahedron arrangement. Diamond is the hardest natural substance. At atmospheric pressure, it melts at 3,550°C
Hydrogen Sulfide
A colorless gas having an odor of rotten eggs. It is fairly soluble in water and is poisonous in rather small concentrations. It burns in excess oxygen to form compounds of water and sulfur dioxide
Sulfur Dioxide
A colorless gas with a suffocating odor
Ethylene Glycol or 1, 2-ethanediol
A colorless liquid, high boiling point, low freezing point. Used as permanent antifreeze in automobiles
Nitrogen Properties
A colorless, odorless, tasteless, and rather inactive gas that makes up about four-fifths of the air in our atmosphere Nature "fixes" nitrogen, or makes nitrogen combine, by means of a nitrogen-fixing bacteria found in the roots of beans, peas, clover, and other leguminous plants
Calorimeter
A container well insulated from outside sources of heat or cold so that most of its heat is contained in the vessel
Transmutation
A conversion of an element to a new element (because of a change in the number of protons)
i (Colligative Properties)
A factor that corrects for the # of particles in a solution from the solute - Find the # of chunks that the compound breaks down into The relative degree of the effect depends only on the number of particles dissolved. However, the number of those particles also depends on the nature of the solute. Using a solute that is an ionic solid and that completely ionizes in an aqueous solution introduces a greater number of particles than when a nonionizing molecular solute is dissolved.
Scintillation Counter
A fluorescent screen (e.g., ZnS) will show the presence of electrons and X-rays, as already mentioned. If the screen is viewed with a magnifying eyepiece, small flashes of light, called scintillations, will be observed. By observing the scintillations, one not only can detect the presence of alpha particles, but also can actually count them
Heat Energy
A form of energy that transfers among particles in a substance (or system) by means of the kinetic energy of those particles
Liquids
A form of matter that has a definite volume and takes the shape of its container. When you consider that in a gas the molecules constitute far less than 1% of the total volume, while in the liquid state the molecules constitute 70% of the total volume, it is clear that in a liquid the forces between molecules are more important. Because of this decreased volume and increased intermolecular interaction, a liquid expands and contracts only very slightly with a change in temperature and lacks the compressibility typical of gases.
Molecular Formula (what it is and how to solve for it)
A formula that shows the actual number of atoms of each element in a compound To get the molecular formula, the molar mass of the unknown compound (given) is compared with the molar mass of the empirical formula (Solve) --> gives you a multiple. Multiply the empirical formula by this multiple
Gas Properties
A gas has neither a definite shape nor a definite volume
Crystal
A geometric form with a repeated pattern structure that is bounded by plane surfaces that make definite angles with each other
Polyatomic Ion
A group of elements that act like a single ion when forming a compound. The group as a whole has an excess charge, which is usually negative, because of an excess of electrons
Liquid Properties
A liquid has a definite volume but takes the shape of the container
Scientific Method
A logical approach to solving problems by observing and collecting data, formulating a hypothesis, and constructing theories supported by the data. The formulating of a hypothesis consists of carefully studying the data collected and organized to see if a testable statement can be made with regard to the data. The hypothesis takes the form of an "if... then" statement. If certain data are true, then a prediction can be made concerning the outcome. The next step is to test the prediction to see if it withstands the experimentation *1. Observing* - Collecting data - Measuring - Experimenting *2. Developing Hypothesis* - Organizing and classifying data - Inferring - Predicting *2.5: Revise or reject hypothesis* *3. Testing* - Predicting - Experimenting - Measuring *4. Theorizing* - Constructing models - Predicting - Communicating *5. Announcing results* - Telling results *5.5: Results confirmed by others/Validate Theory*
Manometer
A manometer is basically a U-tube containing mercury or some other liquid. When both ends are open to the air, the level of the liquid will be the same on both sides since the same pressure is being exerted on both ends of the tube. When there is one end of the U-tube connected to a vessel and the pressure inside the vessel is the same as the atmospheric pressure outside, the levels of liquid are the same. When the pressure inside is greater than outside, the column of liquid will be high on the side that is exposed to the air. When the pressure inside the vessel is less than the outside atmospheric pressure, the additional pressure will force the liquid to a higher level on the side near the vessel
Mass Spectroscopy
A mass spectroscope separates isotopes of the same element based on differences in their mass
Avogadro's Number
A mole is 6.02 x 10²³ particles
Nuclear Fission
A nuclear fission reaction is the splitting of a heavy nucleus into two or more lighter nuclei
Electronegativity
A number that measures the relative strength with which the atoms of the element attract valence electrons in a chemical bond *Trend:* Electronegativity decreases down a group and increases across a period
Bohr's Model of the Atom
A planetary model that quantized the energy of electrons to specific orbits. Bohr's model pictured the atom as having a dense, positively charged nucleus and negatively charged electrons in specific spherical orbits, also called energy levels or shells, around this nucleus. These energy levels are arranged concentrically around the nucleus, and each level is designated by a number: 1, 2, 3,... The closer to the nucleus, the less energy an electron needs in one of these levels, but it has to gain energy to go from one level to another that is farther away from the nucleus The maximum number of electrons = 2n² Example: Principal Energy Level 1 has a maximum number of 2 electrons Principal Energy Level 2 has a maximum number of 8 electrons Principal Energy Level 3 has a maximum number of 18 electrons Principal Energy Level 4 has a maximum number of 32 electrons Principal Energy Level 5 has a maximum number of 50 electrons
Chromatography
A process used to separate parts of a mixture. The component parts separate as the solvent carrier moves past the spot of material to be separated by capillary action.
Pure Substance
A pure substance can be subdivided into the smallest particle that still has the properties of that substance
Element
A pure substance that is made up of only one kind of atom. All parts are the same throughout (homogeneous)
Compound
A pure substance that is made up of two or more kinds of atoms joined together in a definite grouping. Composition is definite (homogeneous). All parts react the same. Properties of the compound are distinct and different from the properties of the individual elements that are combined in its make-up
Heavy Water
A small portion of water is called "heavy" water because it contains an isotope of hydrogen, deuterium (symbol D), rather than ordinary hydrogen nuclei. Deuterium has a nucleus of one proton and one neutron rather than just one proton. Another isotope of hydrogen is tritium. Its nucleus is composed of two neutrons and one proton. Both of these isotopes have had use in the nuclear energy field
Solid Properties
A solid has both a definite size and a definite shape
Hydrate
A substance that holds a definite proportion of water in its crystal structure. Notated with the formula of the compound • __ H₂O (The • is read as "with"). When these crystals are heated gently, the water of hydration can be forced out of the crystal and the structure collapses into an anhydrous (without water) powder.
Catalyst
A substance that is introduced into a reaction to speed up the reaction by changing the amount of activation energy. *The catalyst speeds up the reaction but is not consumed itself*
Hydrogen Peroxide
A well-known bleaching and oxidizing agent *Remember that peroxide has an oxidation number of -1*
Carbon Dioxide
A widely distributed gas that makes up 0.04 percent of the air Made in the laboratory by reacting calcium carbonate (marble chips) with hydrochloric acid The test for carbon dioxide consists of passing it through limewater, (Ca(OH)₂). If CO₂ is present, the limewater turns cloudy because of the formation of a white precipitate of finely divided CaCO₃ Important uses: 1. Because CO₂ is the acid anhydride of carbonic acid, it forms the acid when reacted with soft drinks, thus making them "carbonated" beverages 2. Solid carbon dioxide (-78°C), or "dry ice," is used as a refrigerant because it has the advantage of not melting into a liquid; instead, it sublimes and in the process absorbs 3 times as much heat per gram as ice 3. Fire extinguishers make use of CO₂ because of its properties of being 1.5 times heavier than air and not supporting ordinary combustion. It is used in the form of CO₂ extinguishers, which release CO₂ from a steel cylinder in the form of a gas to smother the fire 4. Plants consume CO₂ in the photosynthetic process, in which chlorophyll (the catalyst) and sunlight (the energy source) must be present. The reactants and products of this reaction are: 6CO₂(g) + 6H₂O(l) → C₆H₁₂O₆(s) + 6O₂(g)
Atmospheric Pressure
AKA air pressure and barometric pressure Approximately equal to the weight of a kilogram mass on every square centimeter of surface exposed to it The pressure of the atmosphere varies with altitude. At higher altitudes, the weight of the overlying atmosphere is less, so the pressure is less. On the average, the air pressure at sea level can support a column of mercury 760 millimeters in height
C₂H₃O₂⁻¹
Acetate
Acid Rain
Acid rain forms when the oxides of sulfur and nitrogen combine with atmospheric moisture to yield sulfuric and nitric acids - both known to be highly corrosive, especially to metals
Hydrofluoric Acid
Acid used to etch glass by reacting with SiO₂ to release silicon fluoride gas. Also used to frost lightbulbs
Naming Ternary Acids
Acids with 3 elements 1. The acid containing one less atom of oxygen than the most common acid is designated by the ending -ous. The name of the acid containing one more atom of oxygen than the most common acid has the prefix per- and the ending -ic; that of the acid containing one less atom of oxygen than the -ous acid has the prefix hypo- and the ending -ous
Group 1 Name
Alkali metals
Alkyl Halides
Alkanes that can be reacted with halogens so that hydrogens are replaced by a halogen atom
Sterling Silver
Alloyed with copper
Physical Change
Alters some aspect of the physical properties of matter, but the composition remains constant (does not alter the identity of the substance)
NH₄⁺¹
Ammonium ion
Alloys
An *alloy* is a mixture of two or more metals 1. Melting Point: The melting point of an alloy is lower than that of its components 2. Hardness: An alloy is usually harder than the metals that compose it 3. Crystal structure: The size of crystalline particles in the alloy determines many of the physical properties. The size of these particles can be controlled by heat treatment. If the alloy cools slowly, the crystalline particles tend to be larger. Thus, by heating and cooling an alloy, its properties can be altered considerably
Nitric Acid
An acid useful in making dyes, celluloid film, and many of the lacquers on cars. Its physical properties are: it is a colorless liquid (when pure), it is one and one-half times as dense as water, it has a boiling point of 86°C, the commercial form is about 68% pure, and it is miscible with water in all proportions Its outstanding chemical properties are: the dilute acid shows the usual properties of an acid except that it rarely produces hydrogen when it reacts with metals, and it is quite unstable and decomposes as follows: 4HNO₃(aq) → 2H₂O(l) + 4NO₂(g) + O₂(g) A good oxidizing agent When nitric acid is mixed with hydrochloric acid, the mixture is called aqua regia because of its ability to dissolve gold
Double Replacement (Double Displacement) Reaction
An actual exchange of "partners" to form new compounds For double replacement reactions to go to completion, that is, proceed until the supply of one of the reactants is exhausted, one of the following conditions must be present: (1) an insoluble precipitate is formed (2) a nonionizing substance is formed - A nonionizing substance keeps its component ions in molecular form and thus eliminates the possibility of reversing the reaction. All neutralization reactions are of this type. (3) a gaseous product is given off
Steel
An alloy of carbon, manganese, sulfur, phosphorous, and silicon Steel is alloyed with nickel and chromium
Bronze
An alloy of copper and tin
Brass
An alloy of copper and zinc
Salt
An ionic compound containing positive ions other than hydrogen ions and negative ions other than hydroxide ions Five methods for preparing salts are as follows: 1. Neutralization Reaction: An acid and a base neutralize each other to form the appropriate salt and water 2. Single Replacement Reaction: An active metal replaces hydrogen in an acid 3. Direct combination of elements 4. Double Replacement Reaction: When solutions of two soluble salts are mixed, they form an insoluble salt compound 5. Reaction of a metallic oxide with a nonmetallic oxide
Excited State
Any level higher than the ground state
Matter
Anything that occupies space and has mass
Properties of Gases
As the temperature of a gas is increased, its kinetic energy is increased, thereby increasing the random motion
Gay-Lussac's Law
At *constant volume*, the pressure of a given mass of gas varies directly with the absolute temperature. Then, P₁/T₁ = P₂/T₂ at constant volume or P₁/T₁ = k *When only gases are involved in a chemical reaction, the volumes of the reacting gases and the volumes of the gaseous products are in small whole-number ratios with each other. Those small whole numbers are the coefficients in the balanced reaction equation.*
Phase Equilibrium
At first, more energetic molecules near the surface are escaping into the gaseous phase faster than some of the gaseous water molecules are returning to the surface and possibly being caught by the attractive forces that will retain them in the liquid phase. After some time, the rates of evaporation and condensation equalize in a *phase equilibrium*
Isotopes
Atoms of the same element that have different masses. The isotopes of a particular element all have the same number of protons and electrons but different numbers of neutrons
Percentage Concentration
Based on the percent of solute in the solution by mass
HCO₃⁻¹
Bicarbonate or Hydrogen Carbonate
Silver hydrogen sulfide test
Black (Ag₂S)
Copper hydrogen sulfide test
Black (CuS)
Iron hydrogen sulfide test
Black (FeS)
Mercury hydrogen sulfide test
Black (HgS)
Nickel hydrogen sulfide test
Black (NiS)
Strontium flame color
Bright red
Bismuth hydrogen sulfide test
Brown (Bi₂S₃)
Lead hydrogen sulfide test
Brown-black (PbS)
CO₃⁻²
Carbonate
Anhydrides
Certain oxides that react with water to form two classes of compounds - acids and bases
Chemical Change
Changes in the composition and structure of a substance (alters the identity of the substance)
Crystalline Solids
Characterized by a three-dimensional representation much like a brick wall. They have a regular structure, in which the particles pack in a repeating pattern from one edge of the solid to the other
Polycrystalline Solids
Characterized by an aggregate of a large number of small crystals or grains in which the structure is regular, but the crystals or grains are arranged in a random fashion
ClO₃⁻¹
Chlorate
ClO₂⁻¹
Chlorite
CrO₄⁻²
Chromate
Glycerine or glycerol or 1,2,3-propanetriol
Colorless liquid, odorless, viscous, sweet taste. Used to make nitroglycerine, resins for paint, and cellophane
Hydrochloric acid
Common acid prepared in the laboratory by reacting sodium chloride with concentrated sulfuric acid. It is used in many important industrial processes
Mixtures
Composition is indefinite (generally heterogeneous). Properties of the constituents are retained. Parts of the mixture react differently to changed conditions. Solutions are mixtures, such as sugar in water, but since the substance, like sugar, is distributed evenly throughout the water, the mixture can be said to be homogeneous
The Law of Definite Composition (or Proportions)
Compounds are made by combining atoms of two or more elements in a definite proportion (or ratio) by mass
Hydrocarbons
Compounds containing only carbon and hydrogen in their structures
Atom
Considered to be the basic building blocks of matter that cannot be easily created nor destroyed
Cu⁺¹
Copper (I) or Cuprous
Cu⁺²
Copper (II) or Cupric
Lithium flame color
Crimson
CN⁻¹
Cyanide
Cycloalkanes
Cycloalkanes form single-bonded ring compounds Cycloalkanes are named by adding the prefix cyclo- to the name of the straight-chain alkane with the same number of hydrocarbons. When there is only one alkyl group attached to the ring, no position number is necessary. When there is more than one alkyl group attached to the ring, the carbon atoms in the ring are numbered to give the lowest numbers possible to the alkyl groups. This means that one of the alkyl groups will always be in position 1. The general formula is C(n)H(2n). If there are two or more alkyl groups attached to the ring, number the carbon atoms in the ring. Assign position number one to the alkyl group that comes first in alphabetical order, then number in the direction that gives the rest of the alkyl groups the lowest numbers possible.
Density Formula
D = m/V *Usually expressed as g/L*
Cr₂O₇⁻²
Dichromate
P Orbitals
Dumbbell shape, oriented on the x, y, and z axes, and can hold a total of 2 electrons each, making a total of 6
Preparation of Hydrogen
Electrolysis of water, which is the process of passing an electric current through water to cause it to decompose, is one method of obtaining hydrogen. Another method of producing hydrogen is to displace it from the water molecule by using a metal. With Potassium, Calcium, and Sodium the reaction is: Very active metal + Water = Hydrogen + Metal Hydroxide. With the metals that react more slowly, a dilute acid reaction is needed to produce hydrogen in sufficient quantities to collect in the laboratory: Active metal + Dilute acid → Hydrogen + Salt of the acid
Law of Conservation of Energy
Energy is neither created nor destroyed in ordinary physical and chemical changes. The system's surroundings must gain the energy that the system loses so that energy is conserved
Kinetic Energy
Energy of motion
Avogadro's Hypothesis
Equal volumes of different gases contain equal numbers of particles at the same temperature and pressure
Buffer Solutions
Equilibrium systems that resist changes in acidity and maintain constant pH when acids or bases are added to them Practically speaking, there are two ways to construct a buffer: 1. Dump approximately equal molar amounts of a weak acid and the salt of its conjugate base OR a weak base and the salt of its conjugate acid into the same container. - For example: Place approximately equal molar amounts of HF (weak acid) and NaF (salt of the conjugate base F⁻¹). - For example: Place approximately equal moral amounts of NH₃ (weak base) and NH₄Br (salt of the conjugate acid) 2. Add a strong acid to a weak base to generate the conjugate acid OR add a strong base to a weak acid to generate the conjugate base. *However, for both the weak acid and conjugate base OR the weak base and conjugate acid to both be present you must use FEWER moles of strong acid or strong base.*
Esters
Esters are often compared to inorganic salts because their preparations are similar. To make a salt, you react the appropriate acid and base. To make an ester, you react the appropriate organic acid and alcohol. The name is made up of the alkyl substituent of the alcohol and the acid name, in which -ic is replaced with -ate. Esters usually have sweet smells and are used in perfumes and flavor extracts. The characteristic group of an organic ester is -COO- General Equation: Alcohol + Acid → Ester + HOH
Distillation
Evaporate, then condense This method of purification will remove any substance that has a boiling point higher than the substance you are trying to purify. It cannot remove dissolved gases or liquids that boil off before the substance you want purified. Distillation is used to purify water
Law of Definite Composition
Every time a particular compound forms, it forms in the same percent composition
Prefixes for Metric System
Exa- (E) 10¹⁸ Peta- (P) 10¹⁵ Tera- (T) 10¹² Giga- (G) 10⁹ Mega- (M) 10⁶ Kilo- (k) 10³ Hecto- (h) 10² Deka- (da) 10¹ Deci- (d) 10⁻¹ Centi- (c) 10⁻² Milli- (m) 10⁻³ Micro- (µ) 10⁻⁶ Nano- (n) 10⁻⁹ Pico- (p) 10⁻¹² Femto- (f) 10⁻¹⁵ Atto- (a) 10⁻¹⁸
When do the concentrations of all participants change most rapidly?
Experiments have shown, that for most reactions, the concentrations of all participants change most rapidly at the beginning of the reaction; that is, the concentration of the products shows the greatest rate of increase, and the concentrations of the reactants the highest rate of decrease, at this point. This means that *the rate of a reaction changes with time*
Pressure
Force per unit area
Binary Covalent Compounds (what are they and how to name them)
Formed between two nonmetals Name by using these steps: 1. The first element in the formula is named first, using the full elemental name 2. The second element is named as if it were an anion and uses its elemental name 3. Prefixes are used to denote the number of the second element present 4. The prefix mono- is never used for naming the first element
Fullerenes
Found in soot that forms when carbon-containing materials are burned with limited oxygen. Their structure consists of near-spherical cages of carbon atoms resembling geodesic domes
Fluorine (state and color at room temperature)
Gas - Pale yellow
Chlorine (state and color at room temperature)
Gas - green
Double and Triple Bonds
Greater energy is required to break double bonds than single bonds, and triple bonds than double bonds. Also, since these stronger bonds tend to pull atoms closer together, the atoms joined by double and triple bonds have smaller inter-atomic distances and greater bond strengths, respectively
Barium flame color
Green
Silver Bromide and Silver Iodide
Halides used on photographic film. Light intensity is recorded by developing as black metallic silver those portions of the film upon which the light fell during exposure
How does heating affect the rate of solution making
Heating increases the rate of solution making by increasing molecular action and giving rise to mixing by convection currents (this heating affects the solubility as well as the rate of solubility)
Mercury (I)
Hg₂²⁺
Gamma Rays
High-energy radiations similar to X-rays (electromagnetic radiation identical with light; high energy) 1. Beta particles and gamma rays are usually emitted together; after a beta is emitted, a gamma ray follows 2. Arrangement in nucleus is unknown. Same velocity as visible light 3. Range: no specific range 4. Shielding needed: about 13 cm of lead 5. Interactions: weak of itself; gives energy to electrons, which then perform the ionization
Accuracy
How close a measurement is to its known or accepted value
Deliquescent (Hydroscopic)
Hydrate which absorb water from the air and become wet
Efflorescent
Hydrated crystals that lose the water of hydration on exposure to air at ordinary temperatures
H₃O⁺
Hydronium ion
OH⁻¹
Hydroxide
ClO⁻¹
Hypochlorite
If an aqueous equilibrium has water removed, where does the equilibrium shift?
If some water were removed (by evaporation), the reaction would shift to the side with less aqueous species
Charles's Law (V/T = k)
If the *pressure remains constant*, the volume of a gas varies directly as the absolute temperature. Then, initial V₁/T₁ = Final V₂/T₂ at constant pressure or V/T = k
Boyle's Law (PV = k)
If the *temperature remains constant*, the volume of a gas varies inversely as the pressure changes. Then, P₁V₁ = P₂V₂ at a constant temperature or PV = k
Primary Alcohol vs Secondary Alcohol
If the -OH is attached to an end carbon, the alcohol is called a *primary alcohol*. If attached to a "middle" carbon, it is called a *secondary alcohol*.
Exothermic Reaction
If the energy released in the formation of a new structure exceeds the chemical energy in the original substances, energy will be given off, usually in the form of heat or light or both
Endothermic
If the heat content of the products is greater than the heat content of the reactants, ∆H is a positive quantity (∆H > 0)
Exothermic
If the heat content of the products is less than the heat content of the reactants, ∆H is a negative quantity (∆H < 0)
If an aqueous equilibrium is diluted, where does the equilibrium shift?
If you were to dilute an equilibrium with extra water, it would shift to the side that has more aqueous species
Dynamic Equilibrium
In a closed system like this, when opposing changes are taking place at equal rates, the system is said to have *dynamic equilibrium*
Pauli Exclusion Principle
In a given atom, no two electrons can have the same four quantum numbers (n, ℓ, mℓ, and ms). Therefore, *each orbital can hold only two electrons with opposite spins*.
Radioactive Dating
In any living organism, the ratio of carbon-14 to carbon-12 is the same as in the atmosphere because of the constant interchange of materials between organism and surroundings. When an organism dies, this interaction stops, and the carbon-14 gradually decays to nitrogen. By comparing the relative amounts of carbon-14 and carbon-12 in the remains, the age of the organism can be established
Coefficients
In balanced chemical reaction equations, coefficients provide mole ratios for reacting substances and substances produced
Metallic Bonds
In most metals, one or more of the valence electrons become detached from the atom and migrate in a "sea" of free electrons among the positive metal ions
Multiplying and Dividing Significant Digits Rules
In multiplication and division, the number of significant figures in a product or a quotient of measured quantities is the same as the number of significant figures in the quantity having the smaller number of significant figures
Ideal Gas Deviations
In the Ideal Gas Law, we assume that the molecules of the gas were not taking up space in the gas volume and that no intermolecular forces of attraction were serving to pull the molecules closer together. *Least deviations occur at low pressures and high temperatures* *High deviations occur at high pressures and very low temperatures* Under high pressures, the molecules will be forced into closer proximity with each other as the volume decreases until the attractive force between molecules becomes a factor. This factor decreases the volume, and therefore the PV values at high pressure conditions will be less than those predicted by the Ideal Gas Law, where PV remains a constant. At very low temperatures, the molecules, because they have slowed down at low temperatures, come into closer proximity with each other and begin to feel the attractive force between them. This tends to make the gas volume smaller and, therefore, causes the PV to be lower than that expected in the ideal gas situation
Indicators
Indicators are acids They have a pH range of color change where there is a color for pHs below the lower pH, a color for pHs above the higher pH, and a mix of those two colors for the middle of the range
Fe⁺²
Iron (II) or Ferrous
Fe⁺³
Iron (III) or Ferric
Iron Ore
Iron ore is refined by reduction in a blast furnace, that is, a large, cylinder-shaped furnace charged with iron ore (usually hematite, Fe₂O₃), limestone, and coke. Molten iron from the blast furnace is called pig iron. From pig iron, the molten metal may undergo one of three steel-making processes that burn out impurities: 1. The basic oxygen furnace uses a lined "pot" into which the molten pig iron is poured. Then a high-speed jet of oxygen is blown from a water-cooled lance into the top of the pot 2. The open-hearth furnace is a large oven containing a dish-shaped area to hold the molten iron, scrap steel, and other additives with which it is charged. Alternating blasts of flame are directed across the surface of the melted metal until the proper proportions of additives are established for that "heat" so that the steel will have the particular properties needed by the customer 3. The electric arc furnace uses enormous amounts of electricity through graphite cathodes that are lowered into the molten iron to purify it and produce a high grade steel
Isomers
Isomers have the same formula, but different structures. The isomers have different properties, both physical and chemical, from those of hydrocarbons with the normal structure
Heisenberg's Uncertainty Principle
It is impossible to know both the precise location and precise velocity of a subatomic particle at the same time
Different types of solute particles
It should also be mentioned that polar molecules that do not ionize in aqueous solution have molecules as solute particles; polar molecules that partially ionize in aqueous solution have a mixture of molecules and ions as solute particles; and polar molecules that completely ionize in aqueous solution have ions as solute particles
Electron Configuration
Just use the periodic table
Celsius to Kelvin Conversion
K = ° C + 273
What type of K Value occurs if an equilibrium involves a transfer of 1 H⁺ to H₂O?
Ka
What type of K Value occurs if an equilibrium involves a transfer of 1 H⁺ from H₂O?
Kb
Equilibrium Constant
Keq If Keq is large, this means that equilibrium does not occur until the concentrations of the original reactants are small and those of the products large. A small value of Keq means that equilibrium occurs almost at once and relatively little product is produced
What type of K Value occurs if 2 ions or 1 ion and something else form a great big messy ion called a complex ion?
Kf
What type of K Value occurs when a solid decomposes into ions?
Ksp (the solubility constant)
What type of K Value occurs if H₂O dissociates into ions?
Kw
Concentrated
Large amount of solute is dissolved in the solvent
Pb⁺²
Lead (II) or Plumbous
Pb⁺⁴
Lead (IV) or Plumbic
Planck's Quantum Theory of Light
Light has both particle-like properties and wave-like characteristics
Arsenic hydrogen sulfide test
Light yellow (As₂S₃)
Bromine (state and color at room temperature)
Liquid - dark red
How does pressure affect the solubility of solids
Little effect
Graphite
Made up of planes of hexagonal structures that are weakly bonded to the planes above and below. This explains graphite's slippery feeling and makes it useful as a dry lubricant. Graphite is also mixed with clay to make "lead" for lead pencils. Graphite is an electrical conductor
Law of Conservation of Mass and Energy
Mass and energy are interchangeable under special conditions E = mc² Energy = mass x (velocity of light)²
Hg₂⁺²
Mercury (I) or Mercurous
Hg⁺²
Mercury (II) or Mercuric
Basic Anhydrides (basic oxides)
Metal oxides that react with water to form bases such as sodium hydroxide, potassium hydroxide, and calcium hydroxide Metal oxide + H₂O → Metal hydroxide
Where are metals and nonmetals found
Metals are found on the left of the periodic table Nonmetals are found on the right side of the periodic table with the most active nonmetal in the upper right-hand corner
Ionic Radius Compared with Atomic Radius
Metals tend to lose electrons in forming positive ions. With this loss of negative charge, the positive nuclear charge pulls in the remaining electrons closer and thus reduces the ionic radius below that of the atomic radius. Nonmetals tend to gain electrons in forming negative ions. With this added negative charge, which increases the inner electron repulsion, the ionic radius is increased beyond the atomic radius
Metal Characteristics
Metals usually have high melting points, show great strength, and are good conductors of electricity
Millikan's Experiment
Millikan was able to measure the charge on an electron using oil droplets sprayed into a chamber with an electric field in front of a telescope. He calculated the mass of a single electron to be 9.11 x 10⁻²⁸ gram
Surface Tension
Molecules at the surface of a liquid experience attractive forces downward, toward the inside of the liquid, and sideways, along the surface of the liquid. On the other hand, molecules in the center of the liquid experience uniformly distributed attractive forces. This imbalance of forces at the surface of a liquid results in surface tension. The uneven forces make the surface behave as if it had a tight film stretched across it.
Unsaturated
More solute can go into solution at that temperature. The solvent has further capacity to hold more solute
Periodic Law
Moseley stated that the properties of elements are a periodic function of their atomic numbers, thus changing the basis of the periodic law from atomic weight to atomic number
Dilution
M₁V₁ = M₂V₂ 1 = solution before 2 = solution after
NO₃⁻¹
Nitrate
NO₂⁻¹
Nitrite
Acidic Anhydrides (acidic oxides)
Nonmetallic oxides that react with water to form an acid such as sulfuric acid, carbonic acid, or phosphoric acid Nonmetallic oxide + H₂O → Acid
Naming Alkane Substitutions
One method of naming a substitution product is to use the alkyl name for the respective chain and the halide as shown above. The halogen takes the form of fluoro-, bromo-, iodo-, and so on, depending on the halogen, and is attached to an alkane name. It precedes the alkane name; for example, bromomethane. The name of the longest carbon chain is the parent chain. The carbon atoms are numbered in the parent chain to indicate where branching or substitution takes place. The direction of numbering is chosen so that the lowest numbers possible are given to the side chains. The complete name of the compound is arrived at by first naming the attached group, each of these being prefixed by the number of the carbon to which it is attached, and then the parent alkane. If a particular group appears more than once, the appropriate prefix (di, tri, and so on) is used to indicate how many times the group appears. A carbon number must be used to indicate the position of each such group. If two or more of the same group are attached to the same carbon atom, the number of the carbon atom is repeated. If two or more different substituted groups are in a name, they are arranged alphabetically.
Atmosphere to Pascal and Kilopascal
One standard atmosphere (1 atm) is equal to 101,325 Pascals or 101.325 Kilopascals
Atmosphere to mmHg/Torr
One standard atmosphere (1 atm) is equal to 760 millimeters of mercury (760 mmHg) or 760 torr
Single Replacement (Single Displacement) Reaction
One substance displaces another A prediction of the feasibility of this type of reaction can be based on a comparison of the heat of formation of the original compound and that of the compound to be formed. *Basically, find ∆H using Hess' law* Another simple way of predicting single replacement reactions is to check the relative positions of the two elements in the activity series below. *If the element that is to replace the other in the compound is higher on the chart, the reaction will occur. If it is below, there will be no reaction.*
Aufbau Principle
Only one electron will fill each orbital until each has one electron. An electron occupies the lowest energy orbital that can receive it
Antimony hydrogen sulfide test
Orange (Sb₂S₃)
Calcium flame color
Orange-red
Amino Acids
Organic acids that contain one or more amino groups. The simplest uncombined amino acid is glycine, or amino acetic acid, NH₂CH₂-COOH
C₂O₄⁻²
Oxalate
Oxidation States (Numbers)
Oxidation states are designated by a small number superscript preceded by a plus or minus sign. This is not to be confused with the ionic charges we have been using thus far that are shown as plus or minus signs to the right of the magnitude of ionic charge as a superscript *Oxidation states may be expressed in fractions* *Negative numbers indicate responsibility for electrons it is sharing in its bond* The sum of oxidation states must be zero for an electrically neutral compound. For a polyatomic ion, the sum of the oxidation states must be equal to the charge on the ion. 1. The oxidation state of an element of an atom in an element is 0 2. The oxidation state of a monoatomic ion is the same as its charge 3. The oxidation state for fluorine is -1 in its compounds 4. The oxidation state of oxygen is usually -2 in its compounds (*Exceptions occur when the oxygen is bonded to fluorine and the oxidation state of fluorine takes precedence, and in peroxide compounds where the oxidation state is assigned the value of -1*) 5. The oxidation state of hydrogen in most compounds is +1 (*Exception occurs in hydrides, where hydrogen acts like an anion compounded with a metal, and hydrogen is assigned the value of -1*)
Properties of Oxygen
Oxygen is a gas under ordinary conditions of temperature and pressure, and it is gas that is colorless, odorless, tasteless, and slightly heavier than air. Oxygen is only slightly soluble in water. Although oxygen will support combustion, it will not burn
Ozone
O₃ The ozone layer prevents harmful wavelengths of ultraviolet (UV) light from passing through Earth's atmosphere
Ideal Gas Law
PV = nRT R = 0.0821 (L x atm)/(mol x K)
Hund's Rule of Maximum Multiplicity
Pairing will occur with the addition of one more electron to each orbital
ClO₄⁻¹
Perchlorate
Periods vs. Groups
Periods are the horizontal row 1-7. Groups are the vertical columns 1-18.
MnO₄⁻¹
Permanganate
O₂⁻²
Peroxide
PO₄⁻³
Phosphate
PO₃⁻³
Phosphite
Naming Binary Acids
Place the prefix hydro- in front of the stem or full name of the nonmetallic element and add the ending -ic
Alpha Particles
Positively charged (+2) particles of helium nuclei (helium nucleus ⁴₂He) 1. Ejection reduces the atomic number by 2, the atomic weight by 4 amu 2. High energy, relative velocity 3. Range: about 5 cm in air 4. Shielding needed: stopped by the thickness of a sheet of paper, skin 5. Interactions: produces about 100,000 ionizations per centimeter; repelled by the positively charged nucleus; attracts electrons, but does not capture them until its speed is much reduced 6. An example: Thorium-230 has an unstable nucleus and undergoes radioactive decay through alpha emission. The nuclear equation that describes this reaction is: ²³⁰₉₀ Th → ⁴₂ He + ²²⁶₈₈ Ra In a decay reaction like this, the initial element (thorium-230) is called the parent nuclide and the resulting element (radium-226) is called the daughter nuclide
Spontaneous Disintegration
Produces the gas known as radon
Chemical Properties
Properties that can be observed in regard to whether or not a substance changes chemically, often as a result of reacting with other substances
Physical Properties
Properties that can usually be observed with our senses
Colligative Properties
Properties that depend primarily on the concentration of particles and not the type of particle
Mendeleev
Proposed a table containing 17 columns and is usually given credit for the first periodic table since he arranged elements in groups according to their atomic weights and properties. Mendeleev is given credit for the first Periodic Table. It was based on placement by properties
How does pulverizing affect the rate of solution making
Pulverizing increases the rate of solution making by increasing the surface area exposed to solvent
What is not included in equilibrium constants?
Pure solids and pure liquids
Sulfuric Acid Properties
Reacts like other acids: With active metals: Zn(s) + H₂SO₄(aq) → ZnSO₄(aq) + H₂(g) With bases: 2NaOH(aq) + H₂SO₄(aq) → Na₂SO₄(aq) + 2H₂O(l) With metal oxide: MgO(s) + H₂SO₄(aq) → MgSO₄(aq) + H₂O(l) With carbonates: CaCO₃(s) + H₂SO₄(aq) → CaSO₄(aq) + H₂O(l) + CO₂(g) As an oxidizing agent: Cu(s) + 2H₂SO₄(aq) (concentrated) → CuSO₄(aq) + SO₂(g) + 2H₂O(l) As a dehydrating agent with carbohydrates: C₁₂H₂₂O₁₁ (sugar) → (H₂SO₄(concentrated) as a dehydrating agent) 12C(s) + 11H₂O(l)
Noble Gas Notation
Represent all of the lower filled orbitals up to the closest noble gas. By enclosing its symbol in brackets, it represents all of the complete noble gas configuration. Then, the remaining orbitals are written in the usual way
Resonance Structures
Resonance structures are hybrids of the possible drawings because no 1 Lewis structure can represent the situation. *To represent this situation, the possible alternatives are drawn with arrows between them*
Allotropes of Sulfur
Rhombic - Shape: Rhombic or octahedral crystals - Color: Pale-yellow, opaque, brittle Allotropic Form Monoclinic - Shape: Needle-shaped monoclinic crystals - Color: Yellow, waxy, translucent, brittle Amorphous - Shape: Noncrystalline - Color: Dark, tough, elastic
Rutherford's Experiment
Rutherford fired alpha particles (helium nuclei) at gold foil; some alpha particles bounced back towards the source. This led Rutherford to conclude that *the atom is mostly empty space* with a *highly concentrated positively charged nucleus* that contained most of the mass of an atom. The electrons define the volume of an atom. The nucleus is made up of still smaller particles called protons. He predicted the existence of a neutral nuclear particle (the neutron), but the neutron wasn't discovered until James Chadwick in 1932
Acid Salts
Salts formed with the HSO₄⁻ (bisulfate ion)
Normal Salts
Salts formed with the SO₄²⁻ (sulfate ion)
Naming Oxygen-containing Polyatomic Ions
Several of the polyatomic anions contain an atom of a given element and a diffferent number of oxygen atoms. When there are two members of such a series, the name of the one with fewer oxygen atoms ends in -ite and the name of the one with more oxygen atoms ends in -ate. Sometimes an element combines with oxygen to form more than just two polyatomic ions. When this occurs, the prefix hypo- is used to name the polyatomic ion with the fewest oxygen ions and the prefix per- to name the polyatomic ion with the most oxygen ions
If the central atom has 3 electron pairs and 1 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: Bent Hybridization: SP² Bond Angles: LLT 120°
If the central atom has 4 electron pairs and 2 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: Bent Hybridization: SP³ Bond Angles: LLT 109.5°
If the central atom has 5 electron pairs and 3 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: Linear Hybridization: DSP³ Bond Angles: 180°
If the central atom has 2 electron pairs and 0 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: Linear Hybridization: SP Bond Angles: 180°
If the central atom has 6 electron pairs and 0 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: Octahedral Hybridization: D²SP³ Bond Angles: 90°, 180°
If the central atom has 4 electron pairs and 1 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: Pyramidal Hybridization: SP³ Bond Angles: LLT 109.5°
If the central atom has 5 electron pairs and 1 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: See Saw Hybridization: DSP³ Bond Angles: LLT (little less than) 120°, 90°, 180°
If the central atom has 6 electron pairs and 2 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: Square Planar Hybridization: D²SP³ Bond Angles: 90°, 180°
If the central atom has 6 electron pairs and 1 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: Square Pyramid Hybridization: D²SP³ Bond Angles: LLT (little less than) 90°, 180°
If the central atom has 5 electron pairs and 2 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: T-Shaped Hybridization: DSP³ Bond Angles: LLT (little less than) 90°, 180°
If the central atom has 4 electron pairs and 0 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: Tetrahedral Hybridization: SP³ Bond Angles: 109.5°
If the central atom has 5 electron pairs and 0 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: Trigonal Bipyramidal Hybridization: DSP³ Bond Angles: 120°, 90°, 180°
If the central atom has 3 electron pairs and 0 lone electron pairs, what is its shape, hybridization, and bond angles?
Shape: Trigonal Planar Hybridization: SP² Bond Angles: 120°
Empirical Formula (what it is and how to solve for it)
Simplest whole number ratio If given mass: Convert the mass to moles and divide all by the smallest number of the moles. The total is the ratios of each element of the compound. If given moles: Divide all by the smallest number of moles. The total is the ratios of each element of the compound. If given percentage composition: Convert percentage composition to mass. Convert the mass to moles and divide all by the smallest number of the moles. The total is the ratios of each element of the compound.
Mole Fraction
Simply the number of moles of that component divided by the total moles of all the components
Dilute
Small amount of solute is dispersed in the solvent
Iodine (state and color at room temperature)
Solid - purplish black crystals
How does temperature affect the solubility of gases
Solubility usually decreases with temperature increase
How does temperature affect the solubility of solids
Solubility usually increases with temperature increase
How does pressure affect the solubility of gases
Solubility varies in direct proportion to the pressure applied to it: *Henry's Law*
Continuum of Water Mixtures
Solutions are clear; may have color Suspensions are cloudy; opaque color Colloids show Brownian movement Suspensions show no Brownian movement
Properties of Metals
Some physical properties of metals are: they have metallic luster, they can conduct heat and electricity, they can be pounded into sheets (are malleable), they can be drawn into wires (are ductile), most have a silvery color, and none are soluble in any ordinary solvent without a chemical change The general chemical properties of metals are: they are electropositive, and the more active metallic oxides form bases, although some metals form amphoteric hydroxides that can react as both acids and bases
Supersaturated
Sometimes, a saturated solution at a higher temperature can be carefully cooled so that the solute does not get a chance to come out of the solution. At a lower temperature, then, the solution will be holding more solute in solution than it should for saturation and is said to be supersaturated. As soon as the solute particles are jarred or a "seed" particle is added to the solution to act as a nucleus, they rapidly come out of solution so that the solution reverts to the saturated state
Orbitals
Specific wave functions. The electron does not move in a circular orbit in this model. Rather, the orbital is a three-dimensional region around the nucleus that indicates the probable location of an electron but gives no information about its pathway
Net Ionic Equation
Spectator ions, ions that appear on both sides of the equation, are omitted from the net ionic equation
Catalysts
Speeds up the rate of reactions by lowering the activation energy needed for a reaction. A catalyst is not consumed
S Orbitals
Spherical and can hold 2 electrons
How does stirring affect the rate of solution making
Stirring increases the rate of solution making by bringing more solvent that is unsaturated into contact with solute
Charge
Stored energy
Potential Energy
Stored energy due to overcoming forces in nature
Beta Particles
Streams of high-speed electrons (-1) (fast electron) 1. Ejected when a neutron decays into a proton and an electron 2. High velocity, low energy 3. Range: about 12 m 4. Shielding needed: stopped by 1 cm of aluminum or thickness of average book 5. Interactions: weak because of high velocity, but produces about 100 ionizations per centimeter 6. An example: Protactinium-234 is a radioactive nuclide that undergoes beta emission. The nuclear equation is: ²³⁴₉₁ Pa → ²³⁴₉₂ U + ⁰_₁ e
Amphoteric Substances
Substances that can act as either proton donors (acids) or proton receivers (bases), depending upon which other substances they come into contact with These substances donate protons in the presence of strong bases and accept protons in the presence of strong acids
SO₄⁻²
Sulfate
SO₃⁻²
Sulfite
Nonpolar Molecules
Symmetric molecules
Lyman Series
Th emissions consisting of ultraviolet radiation, that occur when an electron cascades from a level higher than the first level down to n = 1
Paschen Series
Th emissions that occur when an electron cascades from a level higher than the third level down to n = 3
Alloy
The "solid solution" of two molten metals mixed together
Alkanes
The alkanes (or paraffin series) have a general formula of C(n)H(2n+2), where n is the number of carbons in the molecule. As the number of carbons in the chain increases, the boiling point also increases. The first four alkanes are gases at room temperature; the subsequent compounds are liquid, then become more viscous with increasing length of the chain. Since the chain is increased by a carbon and two hydrogens in each subsequent molecule, the alkanes are referred to as a homologous series 1. Methane: CH₄ 2. Ethane: C₂H₆ 3. Propane: C₃H₈ 4. n-Butane: C₄H₁₀ 5. n-Pentane: C₅H₁₂ 6. n-Hexane: C₆H₁₄ 7. n-Heptane: C₇H₁₆ 8. n-Octane: C₈H₁₈ 9. n-Nonane: C₉H₂₀ 10. n-Decane: C₁₀H₂₂
Alkene Series (Unsaturated)
The alkene series has a double covalent bond between two adjacent carbon atoms. The general formula of this series is C(n)H(2n). In naming these compounds, the suffix of the alkane is replaced by -ene. If the double bond occurs on an interior carbon, the chain is numbered so that the position of the double bond is designated by the lowest possible number assigned to the first doubly bonded carbon
Alkyne Series (Unsaturated)
The alkyne series has a triple covalent bond between two adjacent carbons. The general formula of this series is C(n)H(2n-2). In naming these compounds, the alkane suffix is replaced by -yne. If there is more than one triple bond, modify the suffix to indicate the number of triple bonds. For example, 2 would be a diyne, 3 would be a triyne, and so on. Next, add the names of the alkyl groups if they are attached. Number the carbon atoms in the chain so that the first carbon atom in the triple bond nearest the end of the chain has the lowest number. If numbering from both ends gives the same positions for two triple bonds, then number from the end nearest the first alkyl group. Then, place the position numbers of the triple bonds immediately before the name of the parent hydrocarbon alkyne and place the alkyl group position numbers immediately before the name of the corresponding alkyl group.
Heat of Vaporization
The amount of energy required at the boiling point temperature to cause the change of phase to occur (liquid → gas)
Heat of Fusion
The amount of energy required at the melting point temperature to cause the change of phase to occur (solid → liquid)
Molar Heat of Fusion
The amount of heat energy required to melt one mole of solid at its melting point
Molar Heat of Vaporization
The amount of heat energy required to vaporize one mole of liquid at its boiling point
calories (lower case c)
The amount of heat needed to raise the temperature of 1 gram of water by 1 degree on the Celsius scale
Aromatics
The aromatic compounds are unsaturated ring structures. The basic formula of this series is C(n)H(2n-6), and the simplest compound is benzene (C₆H₆). Most of the aromatics have an aroma. The C₆H₅ group is a substituent called phenyl. This is the benzene structure with one hydrogen missing. If only two groups are substituted in the benzene ring, the compound formed will be a benzene derivative having three possible isomeric forms. In such cases, the prefixes ortho-, meta-, and para-, abbreviated as o-, m-, and p-, may be used to name the isomers. In the ortho- structure, the two substituted groups are located on adjacent carbon atoms. In the meta- structure, they are separated by one carbon atom. In the para- structure, they are separated by two carbon atoms.
Stable Octet
The arrangement of two s electrons and six p electrons in the valence energy level (8 valence electrons total)
Capillary Action
The attraction of the surface of a liquid to the surface of a solid. A liquid will rise quite high in a very narrow tube if a strong attraction exists between the liquid molecules and the molecules that make up the surface of the tube. This attraction tends to pull the liquid molecules upward along the surface against the pull of gravity. This process continues until the weight of the liquid balances the gravitational force
Principal Quantum Number (n)
The average distance of the orbital from the nucleus. 1 is closest to the nucleus and has the least energy. The numbers are called energy levels
Ethanol
The best known and most used alcohol. Ethanol is a colorless, flammable liquid with a boiling point of 78°C. It is miscible with water and is a good solvent for a wide variety of substances (these solutions are often referred to as "tinctures"). It can be used as an antifreeze because of its low freezing point, -115°C, and for making acetaldehyde and ether. It is presently used in gasoline as an alternative to reduce the use of petroleum.
Naming Ionic Compounds
The binary ionic compounds formed are composed of a positive ion (cation) that is written first and a negative ion (anion) 1. Name the cation first and then the anion 2. The cation takes its name from the name of the element 3. The anion with which the cation combines is named by taking the root of the element's name and adding -ide. The anion's name comes second Multivalent Metals - Iron (II) and Iron (III) - Copper (I) and Copper (II) - Mercury (I) and Mercury (II) - Tin (II) and Tin (IV) - Lead (II) and Lead (IV) *Alternative Naming System for Multivalent Metals:* Instead of using roman numerals, for metals that form only two ions, the ion with the higher charge has a name ending in -ic and the ion with the lower charge has a name ending in -ous
Boiling Point Colligative Property
The boiling point is raised by the addition of more solute ΔTb = Kb x m x i *Use the Kb of the solvent*
Decomposition (Analysis) Reaction
The breakdown of a compound to release its components as individual elements or other compounds If the heat of formation is a high exothermic (∆H is negative) value, the compound will be difficult to decompose since this same quantity of energy must be returned to the compound. A relatively low and negative heat of formation indicates decomposition would not be difficult. A high positive heat of formation indicates extreme instability of a compound, which can explosively decompose
Energy
The capacity to do work. Work is done whenever a force is applied over a distance. Therefore, anything that can force matter to move, to change speed, or to change direction has energy
Properties and Uses of Alkanes
The carbon-hydrogen bonds are nonpolar. The only forces of attraction between nonpolar molecules are weak intermolecular, or London dispersion, forces. These forces increase as the mass of a molecule increases. Smaller alkanes exist as gases at room temperature, while larger ones exist as liquids. Gasoline and kerosene consist mostly of liquid alkanes. Seventeen carbons are needed in the chain for the solid form to occur. Paraffin wax contains solid alkanes. The differences in the boiling points of mixtures of liquid alkanes found in petroleum make it possible to separate the various components by fractional distillation. This is the major industrial process used in refining petroleum into gasoline, kerosene, lubricating oils, and several other minor components.
Molar Heat of Formation
The change in enthalpy that accompanies the formation of 1 mole of a compound from its elements with all substances in their standard states at 25°C
Combustion Reactions
The chemical processes in which substances (called fuels) are rapidly oxidized, accompanied by the release of heat and usually light
Nuclear Fusion
The combination of very light nuclei to make a heavier nucleus. Extremely high temperatures and pressures are required to overcome the repulsive forces of the two nuclei
Meniscus
The curve in the upper surface of a liquid close to the surface of the container or another object, caused by surface tension. It can be either concave or convex, depending on the liquid and the surface
Solvent
The dissolving medium
Electrons moving between energy levels
The electron can exist only in certain energy levels without an energy change but that, when the electron changes its state, it must absorb or emit the exact amount of energy that will bring it from the initial state to the final state. ∆E electron = E final - E initial When an electron moves from the ground state to an excited state, it must absorb energy. When an electron moves from an excited state to the ground state, it emits energy
Valence Electrons
The electrons found in the outermost energy level
Transition Elements
The elements involved with the filling of a d sublevel with electrons after two electrons in the s sublevel of the next principal energy level *Some of these elements gain stability by promoting a 4s electron into the 3d sublevel. This is because the 3d and 4s sublevels are very close in energy and that there is a state of greater stability in half-filled and filled sublevels*. *Transition elements have several common characteristic properties:* - They often form colored compounds - They can have a variety of oxidation states - At least one of their compounds has an incomplete d electron subshell - They are often good catalysts - They are silvery blue at room temperature (except copper and gold) - They are solids at room temperature (except mercury) - They form complex ions - They are often paramagnetic due to unpaired electrons
Balmer Series
The emissions that occur when an electron cascades from a level higher than the second level down to n = 2
Where does the energy released in a nuclear reaction come from?
The energy comes from the fractional amount of mass converted into energy
Activation Energy
The energy necessary to get the reaction going by increasing the energy of the reactants so they can combine
Ionization Energy
The energy necessary to remove an electron *Trend:* Inverse to atomic radius; the smaller the atom, the more tightly packed and harder to remove the electrons are In general, left to right = increases and down = decreases
Second Law of Thermodynamics
The entropy of the universe increases for any spontaneous process. This means that the entropy of a system may increase or decrease but that, if it decreases, then the entropy of the surroundings must increase to a greater extent so that the overall change in the universe is positive
If the volume of the reaction vessel is increased, where does the equilibrium shift?
The equilibrium will shift to the side with the more moles. The pressures will all go down.
Photographic Plate
The fogging of a photographic emulsion led to the discovery of radioactivity. If this emulsion is viewed under a high-power microscope, it is seen that beta and gamma rays cause the silver bromide grains to develop in a scattered fashion
Synthesis
The formation of a compound by uniting its components
Combination (Synthesis) Reaction
The formation of a compound from the unions of its elements -∆H = exothermic reaction +∆H = endothermic reaction If *the heat of formation is a large number preceded by a minus sign*, the combination is likely to occur *spontaneously* and the reaction is exothermic. If, on the other hand, the number is small and negative or is positive, heat will be needed to get the reaction to proceed at any noticeable rate
Freezing Point Colligative Property
The freezing point is lowered by the addition of more solute Δtf = Kp x m x i *Use the Kp of the solvent*
Viscosity
The friction or resistance to motion that exists between the molecules of a liquid when they move past each other. It is logical that the stronger the attraction between the molecules of a liquid, the greater its resistance to flow - and thus the greater its viscosity. The viscosity of a liquid depends on its intermolecular forces. More viscous liquids move more slowly
Reduction
The gain of electrons
General VSEPR Formula for Molecules
The general VSEPR formula for a molecule such as ammonia (NH₃) is AB₃E, where A replaces N, B replaces H, and E represents the unshared electron pair. A water molecule has two unshared electron pairs and can be represented as an AB₂E₂
Organic Acids (Carboxylic Acids)
The general formula is R-COOH. Organic acids can be prepared by the mild oxidation of an aldehyde. The simplest acid is methanoic acid, which is present in ants, bees, and other insects. Notice that the name is derived from the alkane stem by adding -oic. It is possible to have more than one carboxyl group in a carboxylic acid; add a prefix after the stem and before the -oic suffix. For example, in the ethane derivative, it would be ethanedioic acid
Aldehydes
The general formula is RCHO, where R represents a hydrocarbon radical. Aldehydes can be prepared by the oxidation of an alcohol. The aldehyde name is derived from the alcohol name by dropping the -ol and adding -al. Formed from the slight oxidation of a primary alcohol
Amine
The group NH₂⁻ is found in the amide ion and the amino group. Under the proper conditions, the amide ion can replace a hydrogen in a hydrocarbon compound. The resulting compound is called an *amine*. In amides, the NH₂⁻ group replaces a hydrogen in the carboxyl group. When naming amides, the -ic of the common name or the -oic of the IUPAC name of the parent acid is replaced by -amide
Enthalpy
The heat content ∆H = Change of heat content ∆H = H of products - H of reactants
Heat of Combustion
The heat released by the combustion of 1 mole of a substance. Heat of combustion is defined in terms of *1 mole of reactant, whereas the heat of formation is defined in terms of 1 mole of product*
Endpoint of a Titration
The indicator changes color
Spectroscope
The instrument used to examine light emitted by energized atoms. The prism or diffraction grating in the spectroscope disperses the light to allow an examination of the spectra or distinct colored lines
Kilocalories (aka Calories with a Capital C)
The kilocalorie equals 1,000 calories. It is the quantity of heat that will increase the temperature of 1 kilogram of water by 1 degree on the Celsius scale
Oxidation
The loss of electrons
Electropositivity
The lower the electronegativity number, the more electropositive an element is said to be
Ground State
The lowest energy state available to the electron
Entropy
The measure of disorder The entropy of the universe is always increasing Solids → Liquid → Aqueous Solution → Gas
Critical Pressure
The minimum pressure required to liquefy a gas at its critical temperature
Brownian Movement
The molecules in the dispersing medium are in motion and continuously bumping into the colloidal particles, causing them to change direction in a random fashion
Equilibrium Vapor Pressure
The molecules in the vapor that are in equilibrium with the liquid at a given temperature exert a constant pressure
Endothermic Reaction
The new structure needs to absorb more energy than is available from the reactants
Atomic Number
The number of protons
Magnetic Quantum Number (mℓ)
The number of spatial orientations of orbitals s = 1 space-oriented orbital p = 3 space-oriented orbitals d = 5 space-oriented orbitals f = 7 space-oriented orbitals The value of m, can equal -ℓ,...0... + ℓ .
Triple Point
The only temperature and pressure at which all three phases of a pure substance can exist in equilibrium with one another in a system containing only the pure substance
Hydrolysis Reactions
The opposite of neutralization reactions. In hydrolysis, the salt and water react to form an acid and a base 1. The salt of a strong acid and a strong base forms a neutral solution when dissolved in water 2. The salt of a strong base and a weak acid forms a basic solution when dissolved in water 3. The salt of a strong acid and a weak base forms an acid solution when dissolved in water 4. The salt of a weak acid and a weak base forms a neutral solution when dissolved in water
Nucleons
The particles inside the nucleus: protons and neutrons
Effusion
The passage of a gas through a tiny orifice into an evacuated chamber
Equivalence Point of a Titration
The point at which enough acid is added to neutralize all the standard solution in the flask
Inertia
The property of mass to resist change of position or motion
Mass
The quantity of matter that a substance possesses and, depending on the gravitational force acting on it, has a unit of weight assigned to it
Diffusion
The random motion of gases in moving from one position to another
Law of Mass Action
The rate of a chemical reaction is proportional to the product of the concentrations of the reactants
Graham's Law of Effusion (Diffusion)
The rate of effusion of a gas is inversely proportional to the square root of its molecular mass
Avogadro's Law
The relationship between the volume and the number of particles of a gas sample when the temperature and pressure constant is: V/n = k In other words, volume and the number of gas particles are directly related
Density
The relationship of mass to a unit volume
Precision
The reliability or reproducibility of a measurement
Dialysis
The separation of a solution from a colloidal dispersion through a semipermeable membrane
Reaction Mechanism
The series of steps by which the reacting particles rearrange themselves to form the products of a chemical reaction The rate of a reaction is determined by the slowest step of the reaction mechanism (this is called *the rate-determining step*)
Angular Momentum (ℓ) Quantum Number
The shape of the orbital: s, p, d, f (in order of increasing energy). The value of ℓ can = 0, 1,..., n - 1 ℓ = 0 indicates a spherical-shaped s orbital ℓ = 1 indicates a dumbbell-shaped p orbital ℓ = 2 indicates a five orbital orientation d orbital
Which side will an equilibrium shift to when the contents of the reaction vessel are pumped into a smaller container? What will happen to its pressures?
The side with less moles. The pressures will all go up.
Methanol
The simplest alcohol. Methanol is a colorless, flammable liquid with a boiling point of 65°C. It is miscible with water, is exceedingly poisonous, and can cause blindness if taken internally. It can be used as a fuel, as a solvent, and as a denaturant to make ethyl alcohol, unsuitable for drinking.
Alcohols
The simplest alcohols are alkanes that have one or more hydrogen atoms replaced by the hydroxyl group -OH. This is called its functional group. Alcohol's function group is R-OH. A hydroxyl group attached to an alkyl stem. Methanol is the simplest alcohol. The alcohol names are derived from alkanes by replacing the -e ending with -ol.
Molecule
The smallest naturally occurring unit of an element or a compound that retains the characteristics of the original substance. A molecule of a compound has a definite shape that is determined by how the atoms are bonded to or combined with each other
Unit Cell
The smallest portion of the crystal lattice that is repeated throughout the crystal
Solid Characteristics
The solid state has the most ordered system. Particles are fixed in rather definite positions and maintain definite shapes. Particles in solids do vibrate in position, however, and may even diffuse through the solid.
Saturated
The solution is holding all the solute possible at that temperature This is not a static condition. In reality, portions of the undissolved solute continue to go into solution as previously dissolved solute particles re-crystallize. This type of condition - when two opposing processes [like dissolving and crystallization] equal each other in rate - is called an equilibrium state.
How do you rank aqueous solutions based on the range of temperature in which the solution is a liquid
The solution that has the greatest range of temperature over which the solution is a liquid is the one that has the lowest freezing point and the highest boiling point 1. Multiply the number of particles (the i factor) by molality 2. Compare the result of the first step to the molality. The range between those two numbers is the difference in freezing point and boiling point
Spin Quantum Number (ms)
The spin in either of two possible directions. Each orbital can be filled by only two electrons with opposite spins + spin - spin The value of m = +½ or -½
Solute
The substance dissolved
Reducing Agent (Reducer)
The substance that is being oxidized is referred to as a *reducing agent* because it facilitates the reduction of the other substance in the reaction
Oxidizing Agent (Oxidizer)
The substance that is being reduced is referred to as a *oxidizing agent* because it facilitates the oxidation of the other substance in the reaction
Mass Number
The sum of the number of protons and the number of neutrons in the nucleus
Critical Temperature
The temperature above which the liquid phase of a substance cannot exist. Above its critical temperature, no gas can be liquefied regardless of the pressure applied
Melting Point
The temperature at which atomic or molecular vibrations of a solid become so great that the particles break free from fixed positions and begin to slide freely over each other in a liquid state
Boiling Point
The temperature at which the liquid's vapor pressure equals the atmospheric pressure. At this point, the average kinetic energy of the molecules is such that they are rapidly converted from the liquid to the vapor phase within the liquid as well as at the surface
Half-Life
The time required for half of the atoms of a radioactive nuclide to decay
First Law of Thermodynamics
The total energy of the universe is constant and cannot be created or destroyed
Vapor Pressure
The vapor pressure of an aqueous solution is always lowered by the addition of more solute The concentration in the vapor drops and so does the pressure the molecules exert
Average Atomic Mass
The weighted average of the atomic masses of the naturally occurring isotopes of an element
Law of Multiple Proportions
There are some compounds formed by the same two elements in which the mass of one element is constant, but the mass of the other varies. In every case, the mass of the other element is present in a small-whole-number ratio to the weight of the first element
Solubility Curve
These curves show the number of grams of solute that will dissolve in 100 grams (milliliters) of water over a temperature range of 0°C to 100°C To find the solubility at any particular temperature, for example at 50°C, you follow the vertical line up from 50°C until it crosses the curve. At that point you place a ruler horizontally across the page and take the reading on the vertical axis
Metalloids
These elements have certain characteristics of metals and other characteristics of nonmetals
Ionic Solids
These ions do not form an individual molecule in the liquid or solid phase but are arranged into a crystal lattice or giant ion molecule containing many such ions. Ionic solids of this type tend to have high melting points and will not conduct a current of electricity until they are in the molten state
Geiger Counter
This instrument is perhaps the most widely used at the present time for determining individual radiation. Any particle that will produce an ion gives rise to an avalanche of ions, so the type of particle cannot be identified. However, each individual particle can be detected
Thomson's Model of the Atom
Thomson discovered the electron as the first subatomic particle. Thomson found the ratio of the electrical charge of the electron to its mass
Sn⁺²
Tin (II) or Stannous
Sn⁺⁴
Tin (IV) or Stannic
Hydrated Ion
To make molecules or ions of another substance go into solution, water molecules must overcome the forces that hold these molecules or ions together. To make sugar molecules go into solution, the water molecules cluster around the sugar molecules, pull them off, and disperse, forming the solution. For an ionic crystal such as salt, the water molecules orient themselves around the ions (which are charged particles) and again must overcome the forces holding the ions together The water molecules that surround the ion differ in number for various ions, but the whole group is called a *hydrated ion*
Semiconductors
Under certain conditions, pure metalloids conduct electricity, but do so poorly, and are thus termed *semiconductors*
Polar Molecules
Unsymmetrical molecules
Fluorides
Used in drinking water and toothpaste to reduce tooth decay
Potassium flame color
Violet (use cobalt-blue glass to screen out Na impurities)
The Universal Solvent
Water is often referred to as "the universal solvent" because of the number of common substances that dissolve in water
Chemical Bond Forming vs Breaking
When a chemical bond forms, energy is released; when this bond is broken, energy is absorbed
Correction of pressure when a gas is collected over water
When a gas is collected over a volatile liquid, such as water, some of the water vapor is present in the gas and contributes to the total pressure. Assuming that the gas is saturated with water vapor at the given temperature, you can find the partial pressure due to the water vapor in a table of such water vapor values. This vapor pressure, which depends only on the temperature, must be subtracted from the total pressure to find the partial pressure of the gas being measured.
Dalton's Law of Partial Pressures
When a gas is made up of a mixture of different gases, the total pressure of the mixture is equal to the sum of the partial pressures of the components; that is, the partial pressure of the gas would be the pressure of the individual gas if it alone occupied the volume. The formula is: Ptotal = Pgas1 + Pgas2 + Pgas3 + ...
Ethers
When a primary alcohol is dehydrated with sulfuric acid, an ether forms. The ether name is made up of two attached alkyl chains to the oxygen. The shorter of the two chains becomes the first part of the name, with the -ane suffix changed to -oxy and the name of the longer alkane chain as the suffix
Hess's Law of Heat Summation
When a reaction can be expressed as the algebraic sum of two or more reactions, the heat of the reaction is the algebraic sum of the heats of these reactions
Common Ion Effect
When a reaction has reached equilibrium, and an outside source adds more of one of the ions that is already in solution, the result is to cause the reverse reaction to occur at a faster rate and reestablish the equilibrium The "common" ion is the one already present in an equilibrium before a substance is added that increases the concentration of that ion. The effect is to reverse the solution reaction and to decrease the solubility of the original substance
Ketones
When a secondary alcohol is slight oxidized, it forms a compound called a ketone. The R' indicates that this group need not be the same as R. The name of the ketone has the ending -one with a digit indicating the carbon that has the double-bonded oxygen preceding the ending in larger chains, as shown in butan-2-one. Another method of designating a ketone is to name the radicals on either side of the ketone structure and use the word ketone. In the preceding reaction, the product would be dimethyl ketone. Note that both aldehydes and ketones contain the carbonyl group in their structures. In the aldehydes, it is at the end of the chain, and, in acids, it is the interior of the chain
Adding and Subtracting Significant Digits Rules
When adding or subtracting measured quantities, the sum or difference should be rounded to the same number of decimal places as the quantity having the least number of decimal places
Alkyl Groups
When an alkane hydrocarbon has an end hydrogen removed, it is referred to as an alkyl substituent or group. The respective name of each is the alkane name with -ane replaced by -yl
Disproportionation
When an element/ion is both reduced and oxidized in a redox reaction
Photons
When energy is released in the "allowed" values, it is released in the form of discrete radiant energy
Correction of difference in the height of the fluid
When gases are collected in eudiometers (glass tubes closed at one end), it is not always possible to get the level of the liquid inside the tube to equal the level on the outside. This deviation of levels must be taken into account when determining the pressure of the enclosed gas. There are then two possibilities (1) When the level inside is higher than the level outside the tube, the pressure on the inside is less, by the height of fluid in excess, than the outside pressure. If the fluid is mercury, you simply subtract the difference from the outside pressure reading to get the corrected pressure of the gas. If the fluid is water, you must first convert the difference to an equivalent height of mercury by dividing the difference by 13.6 (since mercury is 13.6 times as heavy as water) (2) When the level inside is lower than the level outside the tube, a correction must be added to the outside pressure. If the difference in height between the inside and the outside is expressed in terms of water, you must take 1/13.6 of this quantity to correct it to millimeters of mercury. This quantity is then added to the expression of the outside pressure, which must also be in millimeters of mercury.
Law of Conservation of Matter
When ordinary chemical changes occur, the mass of the reactants equals the mass of the products. *In a chemical change, matter can neither be created nor destroyed, but only changed from one form to another*
Ionic Bond
When the electronegativity difference between atoms is 1.7 or greater, the more electronegative atom will borrow the electrons it needs to fill its energy level, and the other atom will lend electrons until it, too, has a complete energy level. Because of this exchange, the borrower becomes negatively charged and is called an anion; the lender becomes positively charged and is called a cation
Non-polar Covalent Bond
When the electronegativity difference between two or more atoms is between 0 and 0.4, the atoms tend to share the valence electrons in their respective outer energy levels. In general, covalent compounds are gases, liquids having fairly low boiling points, or solids that melt at relatively low temperatures. Unlike ionic compounds, they do not conduct electric currents
Polar Covalent Bond
When the electronegativity difference is between 0.4 and 1.6, there will not be an equal sharing of electrons between the atoms involved. The shared electrons will be more strongly attracted to the atom of greater electronegativity, creating dipoles. The atom that is more electronegative—the one that holds electrons more tightly—pulls the electrons closer to itself, creating a partial negative charge there. The less electronegative atom becomes partially positive as a result because it has lost partial possession of the electrons. This is indicated by the use of partial negative (δ-) and partial positive (δ+) signs.
Molecular Speed Distribution in a Gas at Different Temperatures
When the temperature is lowered, the gas reaches a point at which the kinetic energy can no longer overcome the attractive forces between the particles (or molecules) and the gas condenses to a liquid
What does a positive change in entropy and a negative change in entropy mean?
When the ∆S is positive for the system, it means greater disorder When the ∆S is negative for the system, it means less disorder
Miscible
When two liquids are mixed and they dissolve in each other
Immiscible
When two liquids separate and do not mix
Pi Bond
When two p orbitals share electrons in a covalent bond and the interaction is not symmetrical about a line between the two nuclei
Zinc hydrogen sulfide test
White (ZnS)
Sodium flame color
Yellow
Cadmium hydrogen sulfide test
Yellow (CdS)
When can you drop x in the denominator?
You can only drop the x in the denominator if K is small
[H₃O⁺] and [OH⁻] Relationship
[H₃O⁺][OH⁻] = 1 x 10⁻¹⁴
Rate Law Expression
k = the specific rate constant for the reaction at the temperature of the reaction The exponents are the coefficients of the reactants
pH and pOH Relationship
pH + pOH = 14
Heat Formula
q = SH x m x ∆t q = heat SH = specific heat m = mass ∆t = change in temperature
Weight Formula
w = mg, where m is the mass of the substance and g is a gravitational constant
Gibbs Free Energy
∆G = ∆H - T∆S (T is temperature in kelvins) If ∆G is negative, the reaction is (probably) spontaneous If ∆G is positive, the reaction is improbable If ∆G is 0, the system is at equilibrium and there is no net reaction
Entropy of Universe Equation
∆S universe = ∆S system + ∆S surroundings
