Chemistry Help and Problems
In our chemistry help section, you’ll find a broad range of topics from very basic chemistry all the way through
some more advanced organic chemistry topics. Browse our chemistry topics below, or contact one of our chemistry tutors for private help.
Before you get into the other topics, learning HOW to learn chemistry is a great place to start, and this section will help.
Numbers and Math Operations
What math do you need know for chemistry? This section illuminates those specific operations.
Units, Measures, & Dimensions
Take a look at all the various types of measures and units you need to understand chemistry.
Need to understand how atoms are structured? Get started here.
The Periodic Table
Almost everyone has heard of the periodic table, but do you know how to read it? This section gives you a thorough
history of the periodic table, and explains how elements are divided and grouped in the table.
Take a deep dive on every element on the periodic table.
Mixtures and solutions may seem to have a lot in common, but they’re actually very different. Find out more here.
States of Matter
Matter has a variety of different states, ranging from gases to solids. Learn more about them in this section.
What are the different bonds and how do you create a compound? Get some clarity in this thorough section.
Let’s learn more about writing simple chemical equations and types of reactions. We cover a lot of ground here.
Moles and Percents
What are moles and why do we need them? No, not the animal – although those are great too!
What is stoichiometry and what forms does it take? This section goes into detail.
Redox and Electroplating
Let’s go further into electrochemistry and redox reactions.
What are gases and the laws that govern them? We take a look here.
Acids and Bases
What makes an acid or a base weak or strong? What are acids and bases in the first place? Let’s dig in.
Polyatomic ions are ions with many atoms; they contain more than one element. They are charged just like regular
ions; for example, an ion looks like this: Cl–, while a polyatomic ion looks like this:
ClO3–. While the chloride ion only contains one element – chlorine – the chlorate ion contains
both chlorine and oxygen. Read this lesson for examples of other commonly known polyatomic ions.
Electronegativity is a property of atoms that has to do with the tendency to attract electrons from another atom to
form an ionic bond. Electronegativity is measured using the Pauling scale, which was instated by Linus Pauling. Read
this lesson to find out all about electronegativity!
Endothermic and Exothermic
All reactions can be classified as endothermic (storing energy) or exothermic (releasing energy). This lesson
reviews the ways in which reactions store and give off energy, including items like heat, light, and mechanical energy.
Once you’ve read this lesson, test yourself with a quick practice quiz to review the endothermic and exothermic
Hydrolysis occurs when one adds water to a compound, which causes the compound to break apart into a cation and an
anion. Then, water can bond chemically with the substance, changing its chemical form.These reactions often take place
when ionic compounds dissolve in water. Read on to learn more about the process of hydrolysis!
When a reaction is in a state of dynamic equilibrium, the reaction is reversible. This means that, to maintain
equilibrium, the products break apart to form the reactants. Read this lesson for more information on dynamic
Enthalpy is a state function that is measured in kilojoules per mole. Enthalpy is abbreviated as H in the
Gibbs free energy equation: G = H – TS. Enthalpy can help an observer discern whether a reaction is endothermic or
exothermic based on the enthalpy having a positive or negative value. Read on to find out more about enthalpy!
Like enthalpy, entropy is also a state function that is defined as ΔS, or Sf –
Si. It is a spontaneous reaction that occurs naturally. Entropy measures the disorder of a system. Read this
lesson to learn more about entropy!
Mass spectrometry is used to experimentally determine the molecular weight of a sample by ionizing a molecule and
passing it through electrical and magnetic fields. The observer would then note how the ionized compound responds,
which correlates with the molecular weight in a quantifiable way. Read on to learn more about the intricate process of
Hess’s law is much like solving a puzzle using the change in entropy of a reaction. The result is that one can tell
the change in energy (in kJ/mol) of a reaction. Hess’s law requires a balanced equation with proper coefficients. Read
on for more advice on implementing Hess’s law!
The Born-Haber cycle is a series of chemical processes that are used to calculate the lattice energy of ionic
solids. The Born-Haber cycle can be thought of as a special case of Hess’s law. Read on for a definition of lattice
energy as well as examples of how the Born-Haber cycle is used to calculate lattice energy.
This page identifies different types of bonds, including covalent, polar covalent, ionic, and hydrogen. It explains
how to draw compound structures by counting electrons and placing bonds accordingly. The Octet and Duet rules are also
This page details how electrons are arranged in an atom, including information about the orbitals (s, p, d, and f)
and how to easily tell which orbital an electron is in. You’ll also learn about the diagonal rule and electron
Electron delocalization can be really confusing! In order to understand this concept, one must learn about
resonance, bonding, and aromaticity. Read on for more information about electron delocalization!
The Aufbau principle describes how electrons fill energy levels in an atom. In order to write the electron
configuration of an atom, one must know how the subshells fill. Using the diagonal rule will certainly help with this
process. Read on for more information about the Aufbau principle.
Hybridization occurs when two atomic orbitals combine to form one hybrid orbital. One of the more common types of
hybridization is sp3 hybridization, which is described in detail in this lesson. Read on for more detailed
information on the intricacies of electron orbitals.
Electrolysis occurs in electrolytic cells when an electrical current causes a nonspontaneous oxidation-reduction
reaction. This lesson describes how electrolysis is used, including extracting pure metals from the Earth’s crust. Read
on for more information on the process of electrolysis!
Voltaic cells use chemical energy to do electrical work. A redox reaction occurs, and the electrons are forced
through an electrical circuit. Read on to find out the specifics on how voltaic cells power electrical processes!
The study of nuclear reactions is called radiation chemistry. A nuclear reaction involves the nucleus of an atom.
These types of processes were first discovered by Marie Curie in the late 1800s. Read on for more details about
Introduction to Organic
Introduces carbon structures and interactions between molecules. Basic vocabulary and ideas are introduced
concerning alcohols and hydrocarbons. Combustion of a hydrocarbon is also discussed briefly.
Alkanes and Alkenes
Alkanes and alkenes are both hydrocarbons that follow the standard nomenclature procedures. Learn whether alkanes
and alkenes are saturated or unsaturated, which is more reactive, and how to name a compound by looking at its
structure in this lesson.
Electrophilic Substitutions (EArS Reactions)
When aromatic compounds undergo reactions with electrophiles, a substitution reaction occurs. This reaction is known
as an electrophilic aromatic substitution (EArS or EAS) reaction. Read on for an in-depth description of how these
Halogenoalkanes are exciting because, compared to alkanes, they are very highly reactive when paired with
nucleophiles or bases. Halogenoalkanes are also SP3 hybridized. Read this lesson to find out more information on
Carbonyl Condensation Reactions
A carbonyl condensation reaction occurs between two carbonyl partners and involve nucleophilic addition and α
substitution. This lesson also covers aldol condensation as well as the Robinson annulation reaction. Read on for more
details about these chemical processes.
An elimination reaction occurs when a starting product breaks down into two new products that contain all the atoms
of the original reactant. There are two types: E1 and E2. Read this lesson for more information about elimination
Nucleophilic substitution reactions occur when a nucleophile interacts with an electrophile. Read this lesson for a
step by step explanation of what happens during a nucleophilic substitution reaction.
This lesson also covers nucleophilic substitution including the SN1 and SN2 mechanisms. Effects on kinetic rate,
alkyl group, and more are discussed in this lesson.
Because many students cannot and do not draw organic structures correctly, one of our most prominent chemistry
tutors took the time to explain how to draw cyclohexane rings in great detail. She even shows more than one way to get
a perfect drawing of this ring. Read the lesson to find out how to draw these rings correctly!
Stereoisomers are a category of isomers. Learn about the different categories of isomers in this lesson, and how you will study stereoisomers in chemistry and biochemistry.
Content in this section of Wyzant Lessons has been curated by tutors, as well as by Chemtutor.com creator David Wilner.
David Wilner is a native of Georgia, USA, born just before the end of WWII. Mr. Wilner is happiest when he is explaining things in science (pontificating), so it is natural that he has been a science teacher in high school and a teacher of chemistry at Georgia Perimeter College.
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