Stoichiometry Calculator
Calculate limiting reactants, theoretical yield, and percent yield for chemical reactions
Stoichiometry Calculations
How to Use the Stoichiometry Calculator
Getting Started
- Step 1: Select the calculation type (limiting reactant, theoretical yield, or percent yield)
- Step 2: Enter reactant formulas, coefficients, molar masses, and amounts
- Step 3: Enter product formulas, coefficients, and molar masses
- Step 4: Select the target product and click Calculate
Key Stoichiometry Concepts
- Limiting Reactant: The reactant that runs out first, limiting product formation
- Excess Reactant: Reactants left over after the limiting reactant is consumed
- Theoretical Yield: Maximum amount of product possible from given reactants
- Percent Yield: Actual yield divided by theoretical yield × 100%
Calculation Steps
- Convert to Moles: Use molar mass to convert mass to moles
- Use Mole Ratios: Apply coefficients from balanced equation
- Find Limiting Reactant: Compare moles available per coefficient
- Calculate Products: Use limiting reactant to find theoretical yield
Common Applications
- Industrial Chemistry: Optimizing chemical processes and costs
- Laboratory Work: Planning experiments and ordering chemicals
- Environmental Chemistry: Pollution control and waste treatment
- Pharmaceutical Manufacturing: Drug synthesis and purification
Frequently Asked Questions
How do I identify the limiting reactant?
Convert all reactants to moles, divide by their coefficients, and the smallest result indicates the limiting reactant. This reactant will be completely consumed first.
Why is percent yield usually less than 100%?
Real reactions have side reactions, incomplete reactions, product loss during isolation, measurement errors, and impure starting materials that reduce actual yield.
What if I don't know the molar mass?
Calculate molar mass by adding atomic masses from the periodic table. For example, H₂O = (2 × 1.008) + (1 × 15.999) = 18.015 g/mol.
How do I handle reactions with multiple products?
Select your target product from the dropdown menu. The calculator will determine theoretical yield for that specific product based on the limiting reactant.
What's the difference between theoretical and actual yield?
Theoretical yield is the maximum possible amount calculated from stoichiometry. Actual yield is what you experimentally obtain, usually less due to real-world limitations.
How do I balance chemical equations for stoichiometry?
Ensure the equation is balanced before using this calculator. Equal numbers of each atom type must appear on both sides of the equation.
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