CHEM 1150 General Chemistry I Exam 1 Study Guide

Flashcards covering key vocabulary from the CHEM 1150 General Chemistry I Exam 1 Study Guide, including scientific explanations, matter types, atomic models, forces, atomic interactions, and energy concepts.

Claim

A statement or assertion that answers a question or explains a phenomenon.

Evidence

Scientific data or observations that support or refute a claim.

Reasoning

The logical connection that explains why the evidence supports the claim.

Scientific Theory

A thoroughly tested and widely accepted explanation for a broad set of observations or phenomena.

Scientific Law

A concise statement or mathematical equation that describes a fundamental relationship or regularity in nature, often without explaining why it occurs.

Atom

The basic building block of matter, consisting of a nucleus and orbiting electrons.

Element

A pure substance consisting only of atoms that all have the same number of protons in their atomic nuclei.

Molecule

A group of two or more atoms held together by chemical bonds.

Compound

A substance formed when two or more different elements are chemically bonded together.

Dalton's Atomic Theory

A foundational theory proposing that matter is composed of indivisible atoms, atoms of a given element are identical, and atoms combine in simple whole-number ratios to form compounds.

Electron

A subatomic particle with a negative charge, discovered by J.J. Thompson.

Cathode Ray Experiment

J.J. Thompson's experiment that demonstrated the existence of negatively charged particles (electrons) with a specific charge-to-mass ratio.

Thompson's Model of the Atom

An early model proposing a sphere of uniformly distributed positive charge with negatively charged electrons embedded within it.

Nucleus

The dense, positively charged center of an atom, containing protons and neutrons, discovered by Ernest Rutherford.

Gold Foil Experiment

Ernest Rutherford's experiment which led to the discovery of the atomic nucleus, showing that most of an atom's mass and positive charge are concentrated in a small central region.

Rutherford's Model of the Atom

A model describing a dense, positively charged nucleus at the center with electrons orbiting around it.

Modern Atomic Model

The current understanding of the atom, featuring a dense nucleus of protons and neutrons, surrounded by electrons in probabilistic orbitals.

Force

An influence that can cause an object to change its motion or shape.

Gravity

An attractive force between any two objects with mass.

Electrostatic Force

An attractive or repulsive force between charged particles.

Energy

The capacity to do work or produce heat.

Potential Energy

Stored energy due to position or composition.

Kinetic Energy

Energy of motion.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transferred or transformed.

London Dispersion Forces (LDF)

Weak, temporary attractive forces between all atoms and molecules, arising from instantaneous dipoles. It is a force between atoms/molecules, not a chemical bond.

Factors Impacting LDF

Electron cloud size/polarizability and the shape of the molecule.

Potential Energy Diagram (Atomic Interactions)

A graph showing how the potential energy of two interacting atoms changes with the distance between them.

Potential Energy Minimum (Atomic Interactions)

On a potential energy diagram, this point represents the most stable internuclear distance where attractive and repulsive forces are balanced.

Attractive Forces (Atomic Interactions)

Forces that draw atoms or molecules closer together.

Repulsive Forces (Atomic Interactions)

Forces that push atoms or molecules apart.

Solid Phase

A state of matter characterized by definite shape and volume, with atoms or molecules closely packed and vibrating in fixed positions.

Liquid Phase

A state of matter characterized by definite volume but no definite shape, with atoms or molecules closely packed but able to move past one another.

Gas Phase

A state of matter characterized by no definite shape or volume, with atoms or molecules widely dispersed and moving randomly.

Intermolecular Forces (IMF)

Attractive forces between molecules (e.g., LDF).

Intramolecular Forces

Forces within a molecule, holding atoms together (e.g., covalent bonds).

Energy to Break a Bond/LDF

Energy is absorbed when a chemical bond or London Dispersion Force is broken.

Energy Released in Bond/LDF Formation

Energy is released when a chemical bond or London Dispersion Force is formed.

Thermal Energy

The total kinetic energy of the atoms or molecules in a substance.

Temperature

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

Energy Transfer in a System

The movement of energy from one object or part of a system to another, occurring until thermal equilibrium is reached.