Honors Chemistry - Final Study Guide

basically everything

Subatomic Particles

Particles that when joined together form an atom; they are the proton (which holds a positive charge), the electron (which holds a negative charge), and the neutron (which holds a neutral charge).

Isotope

Form of any given element containing a specific number of neutrons in the nucleus of the atom; represented by its element and mass number.

Atom

Particle that makes up all of matter and is comprised of subatomic particles. Various elements, ions and isotopes can be made depending on how many subatomic particles are found in the particle.

Molecule

Two or more atoms chemically bonded together and share valence electrons and have a specific geometric shape as defined by Lewis Structures. Another word is compound.

Element

Pure substance comprised of a single atom with a specific number of protons. All of these are listed on the periodic table. This cannot be decomposed into smaller parts.

Compound

Pure substance comprised of more than one atom in fixed proportions. They can be decomposed into their elements and are more common in the natural world. Another word is molecule.

Mixture

Substance made of two or more different elements or compounds combined in variable proportions; can be divided into homogeneous and heterogeneous.

Pure Substance

Substance made of just one element or compound.

Ion

Form of any given element containing a specific number of electrons that are gained/lost in a chemical reaction. Some of these may be positive or negative because element naturally strive to have the same number of electrons as the balanced and stable noble gasses. Positive variants are called cations (which can usually be found on the left side of the periodic table), and negative variants are called anions (which can usually be found on the right side of the periodic table).

Predicting Ionic Charges

You can predict what the ionic charge of a main group element will be based on its group. The charges are as follows: 1A is +1, 2A is +2, 3A is +3, 5A is -3, 6A is -2, 7A is -1, and 8A is 0. There are a few elements which also have a predictable ionic charge, such as Ag with a charge of +1, and Zn & Cd with a charge of +2. You cannot predict the charges of transition metals.

Metal

Element that tends to lose electrons during chemical reactions (positive ionic charge) and is a solid at room temperature. Can mostly be found on the left side of the periodic table.

Non-metal

Element that tends to gain electrons during chemical reactions (negative ionic charge) and is a gas at room temperature. Can mostly be found on the right side of the periodic table.

Chemical Change

Change made to a substance that altars the chemical composition of that substance during a chemical reaction. The indicator of this is when a new substance is formed due to the reaction.

Physical Change

Change made to a substance that altars the appearance of the substance, without actually changing the chemical composition of the substance. You can detect this with your five senses after a reaction, but you won’t see any new substances formed.

Chemical Reaction

Reaction between two elements/molecules which altars the chemical composition of the reactants, creating a new substance as a product. There are many types of these, including Synthesis, Decomposition, and Single/Double Replacement.

Precipitation Reaction

Double Replacement reaction where the anions swap which cation they are bonded to. Two new compounds will be formed. An example could be NaCl + AgNO₃ → NaNO₃ + AgCl. To solve these, first write the products, then balance the equation and write the charges of both sides. After, determine the solubility of the products (the reactants will always be aqueous), then write any net ionic equations necessary is a reaction has occurred (there is no reaction if there is no solid).

Solubility of Ions

The solubility of certain ions can be predicted. For example, Li⁺, Na⁺, K⁺, NH₄⁺, NO₃⁻, and C₂H₃O₂⁻ are always soluble while Pb²⁺, CO₃²⁻, and PO₄³⁻ are never soluble unless paired with an always soluble ion.

Redox Reaction

Chemical reaction where electrons transfer during the reaction. This can be when elements become compounds or when elements are ionized and vice versa. Under this category there are Synthesis reactions, where two elements combine to make a new compound, Decomposition reactions, where a compound separates into two elements, and Single Replacement reactions, where an element/ion takes the place of an element/ion in a compound, leaving the other element/ion separate as a second product.

Double Replacement Reaction

Non-redox reaction where all the atoms/molecules are already ionized. The reactants are two compounds, and the products are two different compounds with swapped ions. Three types of these are Precipitation reactions, Acid-Base reactions, and Gas Evolution reactions.

Acid-Base Reaction

Double Replacement reaction where an acid (usually containing H⁺) and a base (usually containing OH⁻) are mixed, creating water and another new compound composed of the two ions paired with the H and OH. The equation for this reaction would be HA + BOH → H₂O + BA, where BA is almost always aqueous. Unless this is not the case for BA, the generic net ionic equation would be H⁺(aq) + OH⁻(aq) → H₂O(l).

Net Ionic Equation

Equation written based on the outcome of a Double Replacement Reaction showing how an insoluble product of the reaction was formed. This shows the actual reaction that took place.

Gas Evolution Reaction

Double Replacement reaction where the products are two compounds, with one of which decomposing into a gas and water, ultimately outputting three products. The following decomposition process is a redox reaction while the initial reaction is not. An example of this reaction could be NH₄A + BOH → NH₄OH + BA, with the resulting reaction being NH₄OH → NH₃(g) + H₂O(l). There will be a net ionic equation for the gas and the water, and if BA is a solid then there will be one for that as well.

Molar Mass

The ratio of grams of a substance to moles of that same substance. Can be devised by dividing the amount of grams you have by the amount of moles you have of the given substance. It is used as the conversion factor relating mole count and gram count as well; when given a number of grams, divide by the molar mass to find mole count, and when given a number of moles, multiply by the molar mass to find gram count.

Stoichiometry

The ratio that relates the moles of one chemical to the moles of another when given an equation. For any chemicals, this would be the amount of the chemical we want used in the reaction (multiplied by how much we are given of said chemical) divided by the amount of the chemical we have used in the reaction. The quotient will be how much of the chemical we want we will be able to make/use in the reaction.