Chemistry 2201 Unit One Terms

Decomposition Reaction

A Reaction where a single compound is broken down into simpler substances.

Unified Atomic Mass Unit

A Unit for measuring the small masses of the atoms. One unified atomic mass unit has a mass of 1.662 x 10 to the -27 kg.

Ionic Compound

A compound made up of a metal and a non metal.

Base

A compound made up of a metal and hydroxide (OH).

Acid

A compound made up of hydrogen and a non metal. H must always be in the beginning of the formula, unless COO is in the middle!

Molecular Compound

A compound made up of two or more non metals.

Solution

A homogeneous mixture; a mixture of uniform composition prepared by dissolving a solute in a solvent.

Solution Stoichiometry

A method of predicting the concentration, volume, or the mass of a substance in a chemical reaction, given the concentration and volume of another substance.

Gas Stoichiometry

A method of using mole ratios to predict the amount (volume, moles, mass) of a gas used in a chemical reaction.

Electron

A negatively charged particle with almost no mass (1/1836 the mass of a proton). Found outside the nucleus.

Nucleus

A small structure located at the centre of the atom and is made up of protons and neutrons. It has a positive charge and is the majority of the mass. It takes up only 10 to the -15 of the volume of the atom.

Unsaturated Solution

A solution capable of dissolving more solute in a given amount of solvent at a given temperature.

Supersaturated Solution

A solution containing more solute than can normally be dissolved in a given solvent at a given temperature. When it cools, the solution will crystallize.

Amalgam

A solution of a liquid in a solid.

Standard Solution

A solution of precisely known concentration made using precision equipment to measure mass of solute and volume of solution.

Alloys

A solution of two or more metals that have been melted together then cooled back to the solid state.

Saturated Solution

A solution that contains the maximum amount of solute that can be dissolved in a given amount of solvent at a given temperature. If you add too much solute, it will settle at the bottom.

Concentrated Solution

A solution that has a large amount of solute dissolved in a given amount of solvent. Anything with a concentration greater than 3.00 mol/L.

Gas

A substance that fills and assumes the shape of its container, diffuses rapidly, and mixes readily with other gasses. It is highly compressible and decreases in volume when pressure is applied. Is affected by temperature change. As temperature increases, the volume and/or the pressure increases.

Solvent

A substance, either solid, liquid, or gas, in which a solute dissolves to produce a solution. However, it is most commonly water. Is a larger quantity than the solute.

Solute

A substance, either solid, liquid, or gas, that dissolves in a solvent to produce a solution. Is a smaller quantity than the solvent.

Miscible

A term referring to two liquid that will dissolve in one another.

Immiscible

A term referring to two liquids that will not dissolve when mixed.

Avagadro's Hypothesis

At a constant temperature and pressure, the volume occupied by a gas depends directly on the number of gas particles (or moles).

Isotopes

Atoms of the same element that have different numbers of neutrons, thus different mass numbers, hence different atomic masses.

Electrolyte Solutions

Compounds that conduct an electric current in aqueous solutions or molten state. Generally include ionic compounds, acids, and bases, which form ions when dissolved in water.

Non-Electrolyte Solutions

Compounds that do not conduct an electric current in aqueous solutions or molten state. Generally includes molecular compounds because they are nonionic.

Molecular Diatomic Elements

Group VIIA (F2, Cl2, Br2, I2) as well as H2, O2, and N2.

Neutron

Has no electric charge, and a mass almost equal to that of a proton. Is found in the nucleus.

Endothermic

Heat energy is absorbed from surroundings.

Exothermic

Heat energy is released.

Hydrocarbon Combustion

Hydrocarbon is a compound that contains only hydrogen and carbon atoms. The products are always carbon dioxide and water vapour.

Mole

Is 6.022 x 10 to 23 particles (atoms, ions, or molecules). Often referred to as Avagadro's number after the scientist who determined it. Is the number of atoms in exactly 12 g of the most common isotope of carbon, carbon 12.

Combustion Reaction

Is a reaction which produces energy (exothermic) in the form of heat and light. Usually oxygen reacting with another substance.

Neutralization Reaction

Is a special type of Double Replacement Reaction where an acid reacts with a base to produce water and a salt.

Composition Reaction

Is the Reaction of two or more substances to form one compound, either ionic or molecular.

Molecular Formula

Is the actual number of atoms of each element in one molecule of the compound.

Actual Yield

Is the amount of product that is actually produced in a chemical reaction when performed in the lab.

Simple Decomposition

Is the breakdown of a compound into its component elements.

Empirical Formula

Is the lowest whole number ratio of atoms or ions in a compound.

Atomic Mass

Is the mass of an atom, measured in grams.

Molar Mass

Is the mass of one mole of particles of a substance. Measured in g/mol, and is found on the periodic table.

Gravimetric Stoichiometry

Is the prediction of the number of moles or the mass of one substance given the moles or mass of another in the reaction.

Percent Yield

Is the ratio of the actual yield to the theoretical yield, expressed as a percent.

Diffuse

Move spontaneously through any available space.

Molecular Monatomic Elements

Noble gasses such as He, Ne, Ar, & Kr.

Percent by Volume %(v/v)

Often used for a liquid dissolved in a liquid solvent.

Polyatomic Elements

P4 and S8.

Proton

Positively charged particle. Each has a mass of 1.67 x 10 to the -24 grams. Found in the nucleus.

Amadeo Avagadro

Proposed that equal volumes of gasses at the same temperature and pressure contain an equal number of molecules.

Dissociation

Refers to the separation of ions. Occurs when ionic compounds, acids, or bases dissolve in water.

Dilute Solution

Solution that has a small amount of solute dissolved in a given amount of solvent. Anything with a concentration less than 3.00 mol/L.

Aqueous Solution

Solutions where water is the solvent.

Standard Temperature and Pressure (STP)

Standard temperature is 0.00 degrees Celsius. Standard Pressure is 102.3 kPa.

Soluble

Term used to describe a solid that dissolves in a liquid.

Insoluble

Term used to describe a solid which does not dissolve in a given liquid.

Molar Volume

The Volume that one mole of a gas occupies at a specified temperature and pressure. Equivalent to 22.4 L/mol at STP.

Theoretical Yield

The amount of product, usually in grams, that is formed based on the stoichiometry of the chemical reaction.

Chemical Reaction

The changing of substances to new substances by the breaking of old bonds and formation of new bonds.

Molar Concentration

The number of moles of solute dissolved in a litre of solution.

Stoichiometry

The prediction of how much of one substance will react with or be produced in a chemical reaction relative to the amount of another substance in the reaction.

Dilution

The process of decreasing the concentration of a solution by adding more solvent.

Mole Ratio

The ratio of one substance to another substance in a balanced chemical equation.

Limiting Reagent

The reactant that is completely consumed in a chemical reaction.

Excess Reagent

The reactant that is present in more that the required amount for a complete reaction.

Atoms

The type of particles found in elements.

Strong Electrolytes

Those in which a large portion of the solute exists as ions. Includes ionic compounds with high solubility, six different acids, and all bases besides one!

Weak Electrolytes

Those where only a small portion of the solute exist as ions. Includes ionic compounds of low solubility, all acids besides six, and one base.

Formula Units

Type of particles found in ionic compounds.

Molecules

Type of particles found in molecular compounds.

Percent by Mass %(m/v)

Used for a solid dissolved in liquid solution. Is the number of grams of solute per 100mL of solution.

Parts per Million (ppm) & Parts per Billion (ppb)

Used to express very small quantities of substances. Describes the mass of the solute compared to the mass of the solvent.

Single Replacement

Where an element and a compound react to produce a different element and compound. Water is always written as HOH for a single replacement!

Double Replacement

Where two compounds react to form two new compounds.