Stoichiometry Calculator

Stoichiometry Calculator

Use this calculator to determine the theoretical yield of a product based on the mass of your reactants and their stoichiometric coefficients in a balanced chemical equation. You can also identify the limiting reactant if two reactants are provided.

Reactant A

Reactant B (Optional, for Limiting Reactant)

Desired Product

Understanding Stoichiometry: The Quantitative Language of Chemistry

Stoichiometry is a fundamental branch of chemistry that deals with the quantitative relationships between reactants and products in chemical reactions. It allows chemists to predict the amount of product that can be formed from a given amount of reactants, or conversely, the amount of reactants needed to produce a desired amount of product. At its core, stoichiometry relies on the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction.

The Balanced Chemical Equation: Your Stoichiometric Map

The starting point for any stoichiometric calculation is a balanced chemical equation. A balanced equation provides crucial information:

• Reactants and Products: It identifies the substances that react and the substances that are formed.
• Stoichiometric Coefficients: These are the numbers placed in front of each chemical formula. They represent the relative number of moles (or molecules) of each substance involved in the reaction. For example, in the reaction 2H₂ + O₂ → 2H₂O, the coefficients tell us that 2 moles of hydrogen react with 1 mole of oxygen to produce 2 moles of water.

Without a correctly balanced equation, any stoichiometric calculation will be inaccurate.

Moles and Molar Mass: The Chemist's Counting Units

In chemistry, we don't typically measure substances in individual atoms or molecules because they are too small. Instead, we use the concept of the mole. A mole is a unit of measurement that represents a specific number of particles (Avogadro's number, approximately 6.022 x 10²³). The mole allows us to relate the macroscopic world (grams we can weigh) to the microscopic world (atoms and molecules).

Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). It is numerically equal to the atomic mass (for elements) or the sum of the atomic masses (for compounds) found on the periodic table. For example, the molar mass of water (H₂O) is approximately 18.015 g/mol (2 x 1.008 g/mol for H + 1 x 15.999 g/mol for O).

The relationship between mass, moles, and molar mass is simple:

Moles = Mass (g) / Molar Mass (g/mol)

Mass (g) = Moles x Molar Mass (g/mol)

Theoretical Yield and Limiting Reactants

When performing a chemical reaction in the lab, you rarely have the exact stoichiometric amounts of all reactants. Often, one reactant will run out before the others. This reactant is called the limiting reactant (or limiting reagent) because it limits the amount of product that can be formed.

The theoretical yield is the maximum amount of product that can be formed from a given amount of reactants, assuming the reaction goes to completion and there are no losses. It is calculated based on the limiting reactant.

Our calculator helps you determine:

1. The number of moles of each reactant you have.
2. Which reactant is the limiting reactant (if you provide two).
3. The theoretical yield of your desired product in both moles and grams.

How to Use the Stoichiometry Calculator

To use the calculator, you'll need a balanced chemical equation and the molar masses of your reactants and desired product. If you don't know the molar masses, you can calculate them from the periodic table.

1. Enter Mass of Reactant A: Input the mass in grams of your first reactant.
2. Enter Molar Mass of Reactant A: Provide the molar mass of Reactant A in g/mol.
3. Enter Stoichiometric Coefficient of Reactant A: This is the number in front of Reactant A in your balanced equation.
4. (Optional) Enter Reactant B Details: If you have a second reactant and want to find the limiting reactant, enter its mass, molar mass, and stoichiometric coefficient. If you only have one reactant, leave these fields blank or zero.
5. Enter Molar Mass of Desired Product: Input the molar mass of the product you are interested in.
6. Enter Stoichiometric Coefficient of Desired Product: This is the number in front of your desired product in the balanced equation.
7. Click "Calculate Theoretical Yield": The calculator will display the moles of each reactant, identify the limiting reactant (if applicable), and show the theoretical yield of your product in both moles and grams.

Example Calculation: Combustion of Glucose

Let's consider the combustion of glucose (C₆H₁₂O₆) with oxygen (O₂) to produce carbon dioxide (CO₂) and water (H₂O):

C₆H₁₂O₆ (s) + 6O₂ (g) → 6CO₂ (g) + 6H₂O (l)

Suppose you have 100 grams of glucose and 50 grams of oxygen, and you want to find the theoretical yield of carbon dioxide.

• Reactant A (Glucose, C₆H₁₂O₆):
  • Mass: 100 g
  • Molar Mass: 180.16 g/mol
  • Coefficient: 1
• Reactant B (Oxygen, O₂):
  • Mass: 50 g
  • Molar Mass: 32.00 g/mol
  • Coefficient: 6
• Desired Product (Carbon Dioxide, CO₂):
  • Molar Mass: 44.01 g/mol
  • Coefficient: 6

Using the calculator with these values will show you the limiting reactant and the theoretical yield of CO₂.

This calculator is a powerful tool for students and professionals alike, simplifying complex stoichiometric calculations and helping you master the quantitative aspects of chemistry.

Moles of Reactant A:

Moles of Reactant B:

Limiting Reactant:

Theoretical Yield of Product:

Moles:

Mass: