Chemical Equations Calculator

Chemical Stoichiometry Calculator

Use this calculator to determine the theoretical yield of a product from a given mass of a reactant, based on a balanced chemical equation. You'll need the molar masses of the reactant and product, and their stoichiometric coefficients from the balanced equation.

function calculateStoichiometry() { var massReactant = parseFloat(document.getElementById('massReactant').value); var molarMassReactant = parseFloat(document.getElementById('molarMassReactant').value); var coeffReactant = parseFloat(document.getElementById('coeffReactant').value); var molarMassProduct = parseFloat(document.getElementById('molarMassProduct').value); var coeffProduct = parseFloat(document.getElementById('coeffProduct').value); // Input validation if (isNaN(massReactant) || isNaN(molarMassReactant) || isNaN(coeffReactant) || isNaN(molarMassProduct) || isNaN(coeffProduct) || massReactant <= 0 || molarMassReactant <= 0 || coeffReactant <= 0 || molarMassProduct <= 0 || coeffProduct <= 0) { document.getElementById('molesReactantResult').textContent = 'Invalid input'; document.getElementById('molesProductResult').textContent = 'Invalid input'; document.getElementById('theoreticalYieldResult').textContent = 'Invalid input'; return; } // Step 1: Calculate moles of reactant var molesReactant = massReactant / molarMassReactant; // Step 2: Use stoichiometric ratio to find moles of product var molesProduct = molesReactant * (coeffProduct / coeffReactant); // Step 3: Calculate mass of product (theoretical yield) var theoreticalYield = molesProduct * molarMassProduct; // Display results document.getElementById('molesReactantResult').textContent = molesReactant.toFixed(4); document.getElementById('molesProductResult').textContent = molesProduct.toFixed(4); document.getElementById('theoreticalYieldResult').textContent = theoreticalYield.toFixed(4); } .chemical-stoichiometry-calculator { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: #f9f9f9; border: 1px solid #ddd; padding: 20px; border-radius: 8px; max-width: 600px; margin: 20px auto; box-shadow: 0 2px 4px rgba(0,0,0,0.1); } .chemical-stoichiometry-calculator h2 { color: #333; text-align: center; margin-bottom: 20px; } .chemical-stoichiometry-calculator p { color: #555; line-height: 1.6; margin-bottom: 15px; } .calculator-form label { display: block; margin-bottom: 8px; color: #333; font-weight: bold; } .calculator-form input[type="number"] { width: calc(100% – 22px); padding: 10px; margin-bottom: 15px; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box; } .calculator-form button { background-color: #007bff; color: white; padding: 12px 20px; border: none; border-radius: 4px; cursor: pointer; font-size: 16px; width: 100%; box-sizing: border-box; transition: background-color 0.3s ease; } .calculator-form button:hover { background-color: #0056b3; } .calculator-results { background-color: #e9ecef; border: 1px solid #dee2e6; padding: 15px; border-radius: 4px; margin-top: 20px; } .calculator-results h3 { color: #333; margin-top: 0; border-bottom: 1px solid #dee2e6; padding-bottom: 10px; margin-bottom: 10px; } .calculator-results p { margin-bottom: 8px; color: #333; } .calculator-results span { font-weight: bold; color: #007bff; }

Understanding Chemical Stoichiometry

Chemical stoichiometry is a fundamental concept in chemistry that deals with the quantitative relationships between reactants and products in a chemical reaction. It's based on the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. This means that the total mass of reactants must equal the total mass of products.

The Importance of Balanced Chemical Equations

Before performing any stoichiometric calculations, it is crucial to have a balanced chemical equation. A balanced equation shows the correct molar ratios (stoichiometric coefficients) of reactants and products. These coefficients are the numbers placed in front of each chemical formula in the equation, ensuring that the number of atoms of each element is the same on both sides of the reaction arrow.

For example, the reaction of hydrogen gas with oxygen gas to form water is:

2 H₂ + O₂ → 2 H₂O

Here, the stoichiometric coefficient for H₂ is 2, for O₂ is 1 (implied), and for H₂O is 2. These coefficients tell us that 2 moles of hydrogen react with 1 mole of oxygen to produce 2 moles of water.

Key Concepts for Stoichiometry Calculations

• Molar Mass (g/mol): The mass of one mole of a substance. It's numerically equal to the atomic or molecular weight expressed in grams. You can find molar masses from the periodic table.
• Moles (mol): A unit of amount of substance. One mole contains approximately 6.022 x 10²³ particles (Avogadro's number). The relationship between mass, moles, and molar mass is: Moles = Mass / Molar Mass.
• Stoichiometric Coefficients: The numbers in a balanced chemical equation that represent the relative number of moles of each reactant and product involved in the reaction.

How the Calculator Works (Step-by-Step)

This calculator performs the following steps to determine the theoretical yield of a product:

1. Convert Mass of Reactant to Moles: Using the provided mass of the reactant and its molar mass, the calculator first determines how many moles of the reactant are present.
2. Use Stoichiometric Ratio to Find Moles of Product: Based on the balanced chemical equation, the calculator uses the ratio of the stoichiometric coefficients of the product to the reactant to convert moles of reactant into moles of product.
3. Convert Moles of Product to Mass (Theoretical Yield): Finally, using the molar mass of the product, the calculator converts the moles of product into its corresponding mass, which is the theoretical yield. The theoretical yield is the maximum amount of product that can be formed from the given amounts of reactants.

Example Calculation: Water Formation

Let's use the example of water formation: 2 H₂ + O₂ → 2 H₂O

Suppose you start with 10 grams of Hydrogen (H₂) and want to find out how much water (H₂O) can be produced.

• Mass of Reactant (H₂): 10 g
• Molar Mass of Reactant (H₂): Approximately 2.016 g/mol (2 * 1.008 g/mol for H)
• Stoichiometric Coefficient of Reactant (H₂): 2
• Molar Mass of Product (H₂O): Approximately 18.015 g/mol (2 * 1.008 g/mol for H + 15.999 g/mol for O)
• Stoichiometric Coefficient of Product (H₂O): 2

Using the calculator with these values:

1. Moles of H₂: 10 g / 2.016 g/mol = 4.9603 mol H₂
2. Moles of H₂O: 4.9603 mol H₂ * (2 mol H₂O / 2 mol H₂) = 4.9603 mol H₂O
3. Theoretical Yield of H₂O: 4.9603 mol H₂O * 18.015 g/mol = 89.36 g H₂O

The calculator will show that 10 grams of hydrogen can theoretically produce approximately 89.36 grams of water.