Chemistry: Matter and Energy Flashcards

Comprehensive vocabulary flashcards covering the basics of chemistry, atomic structure, periodic trends, measurements, stoichiometry, and nuclear chemistry based on Unit 1 and 2 lecture notes.

Chemistry

The study of matter, its composition, structure, properties, reactions, and the energy involved.

Matter

Anything that has mass and takes up space.

Composition

What matter is made of.

Structure

How particles in matter are arranged.

Properties

The measurable characteristics of matter.

Reactions

How matter changes when interacting with other substances.

Substance

A specific type of matter, such as air, blood, water, or Tylenol.

Atomic Scale

A scale of matter that is very small and cannot be seen, even with a light microscope.

Microscopic Scale

Structures that are not visible to the naked eye but can be seen using a microscope, such as cells.

Macroscopic Scale

Structures that are visible to the naked eye, such as liquids and solids.

Solid State

Particles are packed closely together with strong attractive forces and have the least amount of kinetic energy; it has a definite shape and volume.

Liquid State

Particles stay close together but flow around with weaker attractive forces than solids; it has more kinetic energy than solids, a definite volume, but no definite shape.

Gas State

Particles are very far apart and move randomly in all directions with the weakest attractive forces and highest kinetic energy; it has no definite shape or volume.

Work

The act of moving an object against an opposing force.

Energy

The ability to do work; it lacks mass and does not occupy space.

Kinetic Energy

The energy of motion; faster motion equates to more of this energy form.

Temperature

A measure of the average kinetic energy of the particles in a substance.

Heat

Kinetic energy transferred from matter at a higher temperature to matter at a lower temperature until both reach the same average kinetic energy.

Potential Energy

Stored energy that depends on the position or arrangement of particles and the composition of a substance.

Stability

A state of being not likely to fall apart or change; generally, substances with low potential energy possess this trait.

Metric System

A decimal-based measurement system built on powers of $10$, used worldwide in science and medicine.

Imperial System

A measurement system mainly used in the U.S., also known as English or U.S. Customary units.

Metric Base Unit for Length

meter ($\text{m}$)

Metric Base Unit for Mass

gram ($\text{g}$)

Metric Base Unit for Volume

liter ($\text{L}$)

Metric Base Unit for Time

seconds ($\text{s}$)

Metric Base Unit for Temperature

Celsius ($^{\circ}\text{C}$)

Meniscus

The curved surface formed by liquids in a graduated cylinder; volume must be read at the bottom of this curve at eye level.

Volume Displacement

A method to find the volume of irregular objects where the volume of the object equals the final volume minus the initial volume of liquid.

Significant Figures

Digits that show how precise a measurement is, including all certain digits and one estimated digit.

Exact Numbers

Numbers that have no uncertainty and unlimited significant figures, typically coming from counting objects or definitions.

Measured Numbers

Numbers that always have uncertainty because the last digit is estimated based on a measuring tool.

Accuracy

Describes how close a measured value is to the true value.

Precision

Describes how consistent repeated measurements are regardless of the true value.

Scientific Notation

A way to write very large or small numbers using a coefficient between $1$ and $10$ multiplied by a base of $10$ with an exponent.

Dimensional Analysis

The process for converting one unit to another by canceling units using conversion factors.

q.d.

Once daily

b.i.d.

Twice daily

t.i.d.

Three times a day

q.d.s.

Four times a day

Density

A physical property that compares the mass of a substance to its volume ($\text{Density} = \frac{\text{Mass}}{\text{Volume}}$).

Specific Gravity

A unitless ratio of the density of a substance to the density of water at $4^{\circ}\text{C}$ ($1.00\,\text{g/mL}$).

Boiling Point of Water

$212^{\circ}\text{F}$, $100^{\circ}\text{C}$, or $373\,\text{Kelvin}$.

Freezing Point of Water

$32^{\circ}\text{F}$, $0^{\circ}\text{C}$, or $273\,\text{Kelvin}$.

Elements

Substances made up of only one type of atom that cannot be broken down into simpler substances; there are $118$ known elements.

Compounds

Substances made up of two or more different elements chemically combined by bonds.

Nucleus

The center of the atom containing protons and neutrons; it contains almost all of the atom's mass.

Proton

A positively charged subatomic particle located in the nucleus with a mass of approximately $1.007\,\text{amu}$.

Neutron

A neutral subatomic particle located in the nucleus with a mass of approximately $1.009\,\text{amu}$.

Electron

A negatively charged subatomic particle located in the electron cloud with a small mass of $0.00055\,\text{amu}$.

Atomic Number

The number value that equals the number of protons in an atom and defines the element.

Mass Number

The total number of particles in the nucleus, calculated as the sum of protons and neutrons.

Period

A horizontal row of elements in the periodic table; all elements in a row have the same number of electron shells.

Group

A column of elements in the periodic table with similar chemical properties and the same number of valence electrons.

Valence Electrons

Electrons in the outermost energy level that determine how atoms bond and the reactivity of the element.

Alkali Metals

Group $1$ ($1\text{A}$) elements that are very reactive, soft, have low density, and typically form a $+1$ charge.

Alkaline Earth Metals

Group $2$ ($2\text{A}$) elements that are reactive metals with high melting points and typically form a $+2$ charge.

Halogens

Group $17$ ($7\text{A}$) reactive non-metals with low melting points that typically form a $-1$ charge.

Noble Gases

Group $18$ ($8\text{A}$) unreactive, colorless, odorless gases with $8$ valence electrons and a charge of $0$.

Atomic Radius

The size of an atom, measured as the distance from the nucleus to the outermost electrons; it increases moving down a group and left across a period.

Electronegativity

How strongly an atom pulls electrons toward itself when forming a bond; it increases going up a group and to the right across a period.

Ionization Energy

The energy required to remove an electron from an atom; it increases going up a group and to the right across a period.

Isotopes

Atoms of the same element with the same number of protons but a different number of neutrons, resulting in a different mass number.

Ground State

The lowest-energy arrangement of electrons in an atom.

Radioisotopes

Isotopes with an unstable nucleus (due to an unbalanced proton to neutron ratio) that undergo radioactive decay to become stable.

Alpha Decay ($\alpha$)

Emission of a particle containing $2$ protons and $2$ neutrons; it has high ionizing power but low penetrating power.

Beta Decay ($\beta$)

Emission of a high-energy electron where the mass number stays the same and the atomic number increases by $1$.

Half-Life

The time required for half of a radioactive sample to decay.

Electromagnetic Radiation

A form of energy traveling through space as waves and particles at the speed of light ($3 \times 10^{8}\,\text{m/s}$).

Ionic Bonding

Occurs when valence electrons are transferred from a metal to a nonmetal, creating an attraction between a cation and an anion.

Cation

A positively charged ion formed when a metal loses electrons.

Anion

A negatively charged ion formed when a nonmetal gains electrons.

Octet Rule

The principle that atoms are most stable when they are surrounded by $8$ valence electrons.

Formula Unit

The lowest whole-number ratio of cations to anions that makes an ionic compound neutral.

Polyatomic Ions

Multiple atoms held together by covalent bonds that possess an overall positive or negative charge.

Covalent Compounds

Compounds formed when valence electrons are shared between non-metals to achieve stability.

Lewis Dot Structure

A diagram showing how atoms in a molecule are arranged and how valence electrons are distributed as bonds or lone pairs.

Mole (mol)

The SI unit for measuring the amount of a substance.

Avogadro's Number

The number of particles in one mole, equal to $6.022 \times 10^{23}$.

Molar Mass

The mass of one mole of a substance, expressed in grams per mole ($g\,mol^{-1}$).

Reactants

The starting substances present before a chemical reaction occurs, found on the left side of the reaction arrow.

Products

The new substances formed as a result of a chemical reaction, found on the right side of the reaction arrow.

Law of Conservation of Mass

States that atoms are not created or destroyed during a chemical reaction; the total mass of reactants must equal the total mass of products.

Stoichiometry

The study of the numerical relationships between the amounts of reactants and products in a chemical reaction.

Combination Reaction

A reaction where two or more substances combine to form a single product ($A + B \rightarrow AB$).

Decomposition Reaction

A reaction where a single compound breaks apart into simpler substances ($AB \rightarrow A + B$).

Oxidation

The loss of electrons during a chemical reaction.

Reduction

The gain of electrons during a chemical reaction.

Combustion

A type of redox reaction where an organic compound reacts with oxygen ($O_2$) to produce carbon dioxide ($CO_2$) and water ($H_2O$).

calorie (cal)

The amount of energy required to raise the temperature of $1\,\text{gram}$ of water by $1^{\circ}\text{C}$.

joule (J)

The metric and SI unit of energy; $1\,\text{cal} = 4.184\,\text{J}$.