Chemistry Concepts

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Common Functional Groups in Organic Chemistry

In organic chemistry, functional groups (or reactive centers) are small structural units within molecules that dictate how most of the compound's chemical reactions occur. Know these common functional [more…]

Periodic Table of Elements

If you’re studying organic chemistry, the periodic table is an important tool. The elements and their atomic numbers are listed and grouped together by their properties — making it easier to remember without [more…]

Chemistry Concepts: Energy Levels and Orbitals

A lot of chemistry is explained by the sharing and trading of electrons between atoms. Understanding how electrons are arranged in an atom is a building block of Chem I. [more…]

Digging the Mole Concept in Chemistry

The mole (abbreviate mol and sometimes called Avogadro's number) is a conversion number that allows a chemist or chemistry student to move from the microscopic world of atoms, ions, and molecules to the [more…]

Identifying Isotopes through Representations

In Chem I, you may have to identify isotopes, which are atoms of the same element that have different numbers of neutrons. The following representation allows you to identify a specific isotope of an element [more…]

Common Measurement Conversions for Chemistry

In order to succeed in your Chem I class, you need to have a firm understanding of basic chemistry measurements and how to convert them from one measurement to another. Following are some important conversions [more…]

The Basic Chemistry of Acids and Bases

A lot of chemistry requires you to understand the difference between acids and bases. An acid is a substance that donates an H+ ion to another chemical species called a base. A [more…]

The Combined Gas Law and Ideal Gas Law

When studying the properties of gases, you need to know the relationships between the variables of volume (V), pressure (P), Kelvin temperature (T), and the amount in moles [more…]

How to Measure Enthalpy Change Using Hess's Law

For the chemist, Hess's law is a valuable tool for dissecting heat flow in complicated, multistep reactions. For the confused or disgruntled chemistry student, Hess's law is a breath of fresh air. In essence [more…]

How to Use Empirical Formulas to Find Molecular Formulas

Many compounds in nature are composed of atoms that occur in numbers that are multiples of their empirical formula. In other words, their empirical formulas don't reflect the actual numbers of atoms within [more…]

How to Perform Mole-Mole Conversions from Balanced Equations

You can balance a chemical equation by adjusting the coefficients that precede reactant and product compounds within the equation. After you've got a balanced equation, you can use the coefficients to [more…]

How to Solve Diffusion and Effusion Problems Using Graham's Law

Different gases diffuse at different rates, depending on their molar masses. You can compare the rates at which two gases diffuse using Graham's law. Graham's law also applies to [more…]

How to Calculate Partial Pressures Using Dalton's Law

When gases mix, each individual gas within the mixture contributes a partial pressure, and adding the partial pressures yields the total pressure. This relationship is summarized by [more…]

How to Predict Solubility Based on Temperature

Increasing temperature magnifies the effects of entropy on a system. Because the entropy of a solute is usually increased when it dissolves, increasing temperature usually increases solubility — for solid [more…]

How to Calculate Concentrations When Making Dilutions

Real-life chemists in real-life labs don't make every solution from scratch. Instead, they make concentrated stock solutions and then make dilutions of those stocks as necessary for a given experiment. [more…]

How to Measure Concentration Using Molarity and Percent Solution

Two important ways to measure concentration are molarityand percent solution. Different solutes dissolve to different extents in different solvents in different conditions. To keep track of all these differences [more…]

Calculate Molecular Masses Using Boiling and Freezing Points of Solvents

A solid understanding of molality helps you to calculate changes in boiling and freezing points. In the same way, a solid understanding of boiling point elevation and freezing point depression can help [more…]

How to Lower and Calculate Freezing Points of Solvents

An important property that you can calculate from molality is freezing point depression. When you add solute to a solvent, it lowers its freezing point. That's why you sprinkle salt on icy sidewalks. The [more…]

How to Elevate and Calculate Boiling Points of Solvents

Boiling point elevation refers to the tendency of a solvent's boiling point to increase when an impurity (a solute) is added to it. In fact, the more solute that is added, the greater the change in the [more…]

How to Calculate Endothermic and Exothermic Reactions

By calculating the enthalpy change in a chemical reaction, you can determine whether the reaction is endothermic or exothermic. Chemical reactions transform both matter and energy. Though chemical equations [more…]

How Temperature, Concentration, and Catalysts Influence Chemical Reaction Rates

Chemists are finicky, tinkering types. They usually want to change reaction rates to suit their own needs. What can affect rates, and why? Temperature, concentration, and catalysts influence rates as follows [more…]

How to Calculate the Empirical Formula of a Compound

If you don't know the empirical formula of a compound, you can analyze samples of the unknown compound to identify the percent composition. From there, you calculate the ratios of different types of atoms [more…]

How to Cancel Spectator Ions to Find a Net Ionic Equation

Because spectator ions don't actually participate in the chemistry of a reaction, you don't always need to include them in a chemical equation. Doing so leads to a needlessly complicated reaction equation [more…]

How to Calculate Percent Yield in a Chemical Reaction

Chemists have to be concerned with just how completely their reactants react to form products. To compare the amount of product obtained from a reaction with the amount that should have been obtained, [more…]

Calculate Limiting Reagents, Excess Reagents, and Products in Chemical Reactions

In real-life chemical reactions, not all of the reactants present convert into product. More typically, one reagent is completely used up, and others are left in excess, perhaps to react another day. The [more…]

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