Chemistry Exam Review - Chapters 1-3

Flashcards to help review key vocabulary and concepts from chemistry lecture notes covering states of matter, mixtures, significant figures, energy, atomic structure, molar mass, isotopes, chemical naming conventions for ionic and covalent compounds, and formula calculations (empirical/molecular).

Gas

A state of matter with no definite shape and no definite volume.

Compound

A substance composed of two or more elements in a fixed, definite proportion.

Heterogeneous Mixture

Two or more substances in variable proportions, where the composition is variable throughout.

Estimated Digit

The last digit in any measured number, which is considered uncertain.

Potential Energy

Energy associated with the position or composition of an object.

Theory

A model that explains and makes predictions about natural phenomena.

Significant Figures (Trailing Zeros)

Zeros located after a number and after a decimal point are considered significant.

Exact Numbers

Numbers that have an unlimited number of significant figures, often from definitions or counting.

Accuracy

How close a measurement is to the true value.

Precision

How close a series of measurements are to one another.

Phosphorus Ion Charge

Typically 3- for phosphorus when forming an ion.

Molar Mass

The mass of one mole of a substance, expressed in grams per mole.

Isotopes

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Oxygen Ion (O2-)

An oxygen atom that has gained two electrons, resulting in 8 protons and 10 electrons.

Alkaline Earth Metals

Elements belonging to Group 2A of the periodic table (e.g., Mg).

Alkali Metals

Elements belonging to Group 1A of the periodic table.

Atomic Number (Z)

The number of protons in an atom's nucleus, which defines the element.

Neutron Count

Calculated by subtracting the atomic number (protons) from the mass number.

Atomic Mass (Weighted Average)

The weighted average mass of an element's isotopes, based on their natural abundances.

Anion Suffix in Binary Compounds

The suffix '-ide' is used for the negatively charged ion in binary compounds.

Ammonium Chloride (NH4Cl)

An ionic compound considered an exception as it does not contain any metals.

Chemical Formula Subscripts

Do not change for a given compound and indicate the fixed ratio of atoms.

Molecular Elements

Elements that exist in nature as polyatomic molecules (e.g., O2, N2, H2).

Ionic Compound Net Charge

Always zero, meaning the sum of positive and negative charges balances out.

Ionic Compound Composition

Always contains both positively charged cations and negatively charged anions.

Carbonic Acid (H2CO3)

An acid that contains the carbonate (CO3^2-) oxyanion.

Variable Charge Metal

A metal that can form ions with more than one possible charge (e.g., Nickel, Chromium, Iron).

Covalent Bond

A chemical bond formed by the sharing of electrons between two nonmetal atoms.

Ionic Bond

A chemical bond formed by the electrostatic attraction between oppositely charged ions, typically between a metal and a nonmetal.

Empirical Formula

The simplest whole-number ratio of atoms in a compound.

Molecular Formula

The actual number of atoms of each element in a molecule.