General Chemistry 1- Chapter 1, 2, 3, 4, 5, 6

Terms and definitions from notes. Ch 1: 1-34 Ch 2: 35-44 Ch 3: 45-57 Ch 4: 58-65 Ch 5: 66-88 Ch 6: 89-

Matter

Anything that occupies space (i.e. volume) and has mass.

Atom

The smallest particle of an element.

Molecule

A collection of atoms chemically bonded together.

Chemistry

The science that seeks to understand the behavior of matter by studying the behavior of atoms and molecules.

Hypothesis

A tentative explanation for a set of observations (a guess).

Scientific Law

A statement that summarizes past observations and predicts future ones (i.e. what).

Scientific Theory

A general explanation of widely observed phenomena that has been extensively tested (i.e. why).

Solid

A state of matter that has a fixed shape and volume with tightly packed particles.

Liquid

A state of matter that has a fixed volume but a changeable shape that occupies volume in a looser fashion.

Gas

A state of matter in which both shape and volume are variable and the particles are loose.

Crystalline

A type of solid in which atoms or molecules are arranged in a pattern with long-range order.

Amorphous

A type of solid with no long-range or repeating order of atoms or molecules.

Pure Substance

A substance that has only one chemical.

Element

The simplest form of matter that has only one kind of atom/symbol.

Compound

A type of matter in which two or more elements are bonded together in a fixed composition.

Mixture

A type of matter made of two or more chemicals.

Homogenous

A type of mixture with uniform composition (one phase).

Heterogenous

A type of mixture with a non-uniform composition (more than one phase).

Distillation

A method used to separate a mixture of liquids based on their boiling points.

Physical Properties

Characteristics that can be observed without changing into another chemical substance (no bonds broken).

Chemical Properties

The tendency of a substance to undergo a chemical reaction with another substance (must break bonds).\

Energy

The capacity to do work.

Work

Force acting through distance.

Kinetic Energy

Energy associated with motion.

Potential Energy

Energy associated with position (height) or composition (reactive).

Thermal Energy (“heat”)

Energy associated with the temperature of objects.

Density

The mass of a substance per unit volume.

Extensive Property

A characteristic that varies with the amount of a substance.

Intensive Property

A characteristic that is independent of the amount of substance.

Precision

The repeatability of a set of measurements and the extent to which they agree.

Accuracy

Agreement between experimental value and true value.

Random Errors

Errors that result from limitations of reading the true scale of the instrument.

Systematic Errors

Errors that result from faulty instrumentation (calibration) or experimental design.

Conversion Factor

Something that expresses some accepted fixed relationship as a fraction in which the numerator and denominator are equivalent, but in different units.

Neutron

An uncharged subatomic particle found in the nucleus.

Atomic Mass Units (amu)

The relative mass scale for atoms and subatomic particles.

Isotopes

Atoms of an element whose nuclei have the same number of protons, but different numbers of neutrons.

Protons

Electrons for neutral atoms.

The Mass Number (A)

The sum of protons and neutrons in one atom of an element.

Mass Spectrometer

A tool that measures precise masses and relative amounts of ions derived from atoms or molecules.

Cation

A positively charged ion (loses e-)

Anion

A negatively charged ion (gains e-)

(1) Mole

The number of atoms in exactly 12 g of pure carbon-12.

Molar Mass (M)

The mass of one mol of particles that comprise a substance in grams.

Molecular Compounds

Compounds composed of atoms held together by covalent bonds.

Ionic Compounds

Compounds that are composed of positively and negatively charged ions, held together by electronic attraction (ionic bonds).

Molecular Formulas

The exact number and type of atoms present in one molecule of a compound.

Empirical Formula

The simplest whole number ratio of elements in a compound.

Formula Unit

The smallest electrically neutral unit within the crystal of an ionic compound.

Oxyanion

An anion containing oxygen and another element (i.e. most polyatomics!)

Hydrates

Ionic compounds which contain a specific number of “waters of hydration” in each formula unit.

Acids

Compounds that generate protons (H+) when dissolved in water (aq/aqueous).

Binary Acid

An acid that contains hydrogen and a nonmetal atom (usually a halogen).

Oxyacids

Acids containing hydrogen and an oxyanion.

Molecular Mass

The mass of one molecule of a molecular compound (amu).

Formula Mass

The mass of one formula unit of a compound (amu)

Molar Mass

The mass (g) of one mol of the particles that comprise a substance.

Chemical Equations

An equation which describes the proportions of substances participating in a chemical reaction.

Combustion Reaction

A reaction which occurs between oxygen (O2) and another substance.

Hydrocarbons

Molecular compounds composed of only hydrogen and carbon.

Limiting Reactant

The reactant (reagent) that is entirely consumed when a reaction goes to completion.

Excess Reactant

Any other reactant that is not completely consumed in a reaction.

Theoretical Yield

The stoichiometric amount of product expected in a reaction.

Actual Yield

The experimentally determined amount of product formed in a reaction.

Percent Yield

Actual Yield / Theoretical Yield x 100%

Solution

A homogeneous mixture of two or more substances.

Solvent

The main substance in a solution (dissolves other materials).

Solute

The substance which gets dissolved in the solvent.

Hydration

The process which occurs when ionic compounds dissolve in water.

Soluble

Dissolves in water.

Insoluble

Does not dissolve in water. 

Molecular Equation

All species written in their “undissociated” forms (i.e. their natural compounds).

Complete Ionic Equation

All dissolved ionic compounds written as disassociated ions.

Net Ionic Equation

Same as complete ionic equation but with “spectator ions” removed.

Spectator Ion

A dissolved ion which does not participate in the reaction.

Arrhenius Acid

An acid that produces H^+ when dissolved in water.

Arrhenius Base

A base which produces OH^- ions when dissolved in water.

Neutralization Reaction

When an acid reacts with a base to produce water and a “salt”.

Titration 

A volumetric method used to determine the concentration of an unknown solution by reacting it with a standard solution. 

Titrant

The solution in the buret. 

Standard Solution

A reference solution of known concentration (usually the titrant).

Equivalence Point

The point when the stoichiometric amounts of reactants are mixed.

Indicator

Substance which changes color during a chemical reaction (signals completion).

End Point 

When the indicator changes color.

Oxidizing Agent

A substance which causes oxidation (pulls electrons away from others).

Reducing Agent

A substance which causes reduction (pushes its electrons onto others).

Oxidation

An increase in oxidation state.

Reduction

A decrease in oxidation state. 

Partial Pressure

Pressure contribution of a gas within a mixture (as if it was in the container by itself).