Regents Review Sheet 4 Naming Chemical Compounds, Shapes of Compounds and Balancing Chemical Equations These are some important points to remember about Naming Compounds. Use this sheet when you do the Review Problems. Rules for Naming Chemical Compounds A) Binary Compounds composed of a Metal and Non-Metal Metal is written first Non-metal is written second, but the ending ide is added to it Ex. NaCl sodium chloride B) Binary Compounds with 2 non-metals Less electronegative element is written first The other element is given the ending-ide Ex. NBr nitrogen bromide C) Other Binary Compounds In some binary compounds in which there can be more than one atom of the same element, we use prefixes to state the number of that atom Ex. CO carbon monoxide CO2 carbon dioxide D) Tertiary Compounds composed of Polyatomic Ions You can find a list of polyatomic ions in the reference tables Metal is written first Polyatomic ion is written last Ex. Na(OH) sodium hydroxide Mg(SO4) magnesium sulfate There is an exception to the rule Ammonium is written first Ex. NH4Cl ammonium chloride E) Binary Acids Hydrogen bound to another element is often a binary acid Write the other element with the prefix hydro-, the suffix ic, then add the word acid Ex. HCL hydrochloric acid H2S hydrosulfuric acid HF hydroflouric acid
F) Ternary Acids-usually are written with H s in front No hydro- prefix Take the polyatomic ion name, change the ending to ic, and add the word acid Ex. H2SO4 sulfuric acid H2CO3 carbonic acid G) Compounds With Metals That Make Multiple Ions Some metals can make several different ions, such as iron Example Fe+2 0-2 makes Fe0 this is called iron (II) oxide the (II) refers to the ion or oxidation state of the metal iron I could also have Fe+3 0-2 come together to make Fe2O3 this is called iron (III) oxide Note: you do the criss-cross method to find these molecular formulas Molecular Shape Or Geometry Linear Molecules All molecules that have just two atoms are linear or in a straight line. Linear molecules with three atoms occur when the center atom is bonded to two other atoms and there are no additional unpaired electrons Trigonal Planar To get a trigonal planar molecular shape, the central atom must be bonded to 3 other atoms and must not have any extra unshared electrons Tetrahedral Central atom is bonded to 4 other outside atoms Pyramidal It looks like a tetrahedral molecule except you have only 3 atoms bound to the central atom and 1 pair of unshared electrons on that central atom.
Balancing Equations Each side of the equation must have the same number of atoms of each element; this is because of the Law of Conservation of Matter. If an element is in a reactant prior to a chemical reaction, then it has to be somewhere in the products after the reaction takes place. By Balancing Equations we insure that this is true. A way to do this is to list your Reactants and Product Al2(SO4) 3 + Ca(OH) 2 Al(OH) 3 + Ca(SO4) Reactants Products 2 Al 1 Al 3 SO4 1 SO4 1 Ca 1 Ca 2 OH 3 OH
Regents Review Sheet 5 Matter and Energy These are some important points to remember about Matter and Energy. Use these sheets when you do the Review Problems. Matter and Energy Chemistry-the study of the composition, structure and properties of matter, the changes that matter undergoes and the energy accompanying those changes A. Substances homogeneous matter having identical properties and composition All samples of a particular substance will have the same heat of vaporization, melting point, etc. Substance include: 1. elements-composed of atoms of the same atomic number; cannot be decomposed by chemical means 2. compounds-two or more different elements chemically combined in a definite ratio by weight; can only be decomposed by a chemical means, not by a physical means Binary compounds-composed of just 2 elements Ternary compounds-composed of 3 elements B. Mixtures-combinations of varying amounts of two or more substances that differ in properties and composition Homogeneous mixture-uniform intermixture of particles; also called solutions One substance dissolves in the other Heterogeneous mixtures-have uniformly dispersed ingredients, but they don t dissolve into one another Energy- The Ability to Do Work Forms of energy- A. mechanical energy B. heat energy C. Radiant energy-light, radio waves, etc. D. chemical energy E. nuclear energy
Types of energy 1. Potential energy- the energy of position 2. Kinetic energy- the energy of motion Heat energy 1. Exothermic reactions-when heat energy is given off 2. Endothermic reactions-when heat energy is absorbed Specific Heat The amount of heat energy required to raise the temperature of 1 g of a material by 1 C Q = m c (change in T) Temperature Average kinetic energy of the particles in a system Converting from Kelvin to Celsius: Kelvin = 273 + Celsius Phases of Matter The term phase refers to the gas (g), liquid (l) or solid (s) forms of matter Solid Phase Atoms or molecules that make up the substance are in a fixed position While these atoms or molecules can t move around freely, they are free to vibrate This vibration increases as the temperature increases Gaseous Phase The molecules are undergoing Translation ( that is, the attractions between the molecules are broken and the molecules are able to move about one another very freely) The molecules also undergo Rotation and Vibration Liquid Phase The atoms or molecules are vibrating, translating, and rotating, but there is still a stronger attraction between these particles than there is in a gas The liquid in a container stays in the container even if its top is open because of this stronger attraction
Heating Curve Boyle s Law-if the temperature is held constant, the volume and pressure will have and inverse relationship P1 V1 = P2 V2 Charles Law - At constant pressure the volume of a given mass of a gas varies directly with the Kelvin temperature V1 = V2 T1 T2 Gay Lussac Law -When the volume is constant, there is a direct relationship between temperature and pressure T1 = P1 T2 P2 The Combined Gas Law Also called The Easy Way To Remember the Gas Law Formulae because instead of memorizing the previous 3 formulae, you only need to memorize this 1 It allows you to also see the effect if two variables of a gas change P1 V1 = P2 V2 T1 T2 Standard Temperature and Pressure (STP) Temperature gas 0 C or 273 K Pressure 760 mmhg or 760 torr or 1atm
Partial Pressures The pressure exerted by each of the gases in a mixture of gases P Total = P gas 1 + P gas 2+ P gas 3 + P gas n Ideal Gas Model A) A gas is composed of individual particles which are in continuous, random, straight-line motion B) Not all particles of a gas have the same kinetic energy, but the K temperature of the gas gives the average kinetic energy of the gas C) Collisions between gas particles are totally elastic. This also holds true for collisions between gas particles and the sides of the container. This means that no kinetic energy is lost when things collide. D) The volume of the gas particles is small compared to the volume of the container E) Gas particles are considered to have no attraction for one another. Hydrogen and Helium are the 2 most ideal gases. Do not forget this! Characteristics of Liquids A) Vapor Pressure-since the molecules in a liquid are freely moving, they collide, transferring energy from one to another. This transfer of energy allows some to break free of the liquid and become gaseous This tends to occur near the surface of the liquid This vapor near the surface actually imparts a pressure on the underlying liquid As temperature increases, so does vapor pressure B) Boiling Point-a liquid will boil at the temperature at which the vapor pressure equals the pressure on the liquid C) Heat of Vaporization-energy required to vaporize (evaporate) a unit mass of a liquid to a gas at constant temperature Characteristics of Solids Density = mass/volume A) Crystals-particles in a crystal vibrate but they keep their regular pattern
B) Melting Point-temperature at which a solid will change to a liquid at 1 atm of pressure C) heat of Fusion-energy required to change a unit mass of a solid to a liquid at a constant temperature Sublimation Occurs when certain substances change from solids directly into gases, without passing into a liquid state Examples are dry ice, iodine crystals and naphthalene