The topics listed below may appear in a variety of first-year high school chemistry courses including college-prep Chemistry and Honors Chemistry. These help pages are based on the idea that you should immerse yourself in topics through problems. Rather than textbook explanations or notes these topics pages focus on understanding concepts through the typical types of problems you might encounter.

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Preview of the topic pages: Density | Limiting reactant

Chemistry Help Topics

Matter and Measurement

States of Matter


Scientific Notation


Dimensional Analysis (Unit Conversions)

Significant Figures

... Counting

... Addition & Subtraction

... Multiplication & Division

Accuracy vs. Precision

Atomic & Electronic Structure/

Periodic Table

Isotopic Notation

Periodic Trends

... Atomic radius trend

... ion radius trend

... ionization energy

... electron affinity trend

... metallic nature trend

Shielding / Zeff


Electron Configuration

Quantum numbers

Paramagnetism and Diamagnetism

Introduction to Light

UV-VIS spectroscopy


Ionic compounds

Covalent/ Molecular Compounds


Simple Organic

Bonding and Intermolecular Forces (IMFs)

Lewis Structures

Expanded Octet


Formal Charge

VSEPR Theory


Intermolecular Forces

... London Dispersion

... Dipole-Dipole

... Hydrogen bonding

... Ion-Dipole


Surface Tension

Capillary Action

Boiling Point Comparison

The Mole

Molar Mass

Mass Percent

Avogadro's Number

Empirical Formula

... by Percent Composition

... by mass

Combustion Analysis

Molecular Formula

Chemical Reactions

Balancing Equations

Balancing Combustion Equations

Types of Reactions, Intro

Single Replacement

Precipitation/ Double Replacement


Stoichiometry, General

Molar Ratio

Limiting reactant

Excess reactant

Gas stoichiometry (at STP)

Gas stoichiometry (PV=nRT)

Solution stoichiometry

Other stoichiometry

Percent Yield/ Percent Error

Gas Behavior

Gas Laws

... Combined Gas Law

... Boyle's Law (P,V)

... Charles' Law (T,V)

... Gay-Lussac's Law (T,P)

... Avogadro's Law (V,n)

Ideal Gas Law

Kinetic Molecular Theory

Dalton's Law of Partial Pressures

Graham's Law

Maxwell-Boltzmann distribution

Real vs. Ideal gas behavior

Van der Waals equation



Preparing a solution

Dilution (moles)

Dilution (volume)

Solubility rules

Molecular, Net Ionic Equations

Colligative properties


Heat Flow

Energy diagrams

Thermochemical equations

Heating/ Cooling curves

Specific Heat Capacity

Hess's Law

Enthalpies of formation

Bond enthalpies


Collision Theory

Rate Comparisons

Integrated Rate Law

Differential Rate Law



Equilibrium Expression

Calculating K

K vs Q

Le Chatelier's Principle

Acids & Bases


Conjugate Acids & Base Pairs

Autoionization of water

pH Scale

Relative strength

Strong Acid/ Base

Ka and Kb

Common Ion Effect



... Strong Acid w/ Strong Base

... Weak acid w/ Strong base

... Weak base w/ Strong acid


pH salts

Entropy and Free Energy


Gibb's Free Energy

G and Temperature

Redox and Electrochemistry

Oxidation numbers

Half Reactions

Balancing Redox reactions

Voltaic cells

Cell potential (standard conditions)

Cell potential (non-standard)