5 steps for solving stoichiometry problems involving limiting reactants by solving for the limiting reaction first
a) Step 1: Write the balanced chemical equation.
b) Step 2: Calculate the molar mass of each reactant.
c) Step 3: Convert the mass of each reactant to moles.
d) Step 4: Use the stoichiometry of the balanced equation to find the moles of the product.
e) Step 5: Compare the moles of the product obtained from each reactant and identify the limiting reactant.
The Correct Answer and Explanation is :
Steps for Solving Stoichiometry Problems Involving Limiting Reactants:
- Write the balanced chemical equation:
- The first step is to write out the balanced chemical equation for the reaction. This ensures that the number of atoms of each element is conserved on both sides of the equation. It is essential to have the correct coefficients to represent the correct proportions of reactants and products.
- Calculate the molar mass of each reactant:
- To proceed with stoichiometry, you need to know the molar mass of each reactant, which is calculated by adding up the atomic masses of the elements that make up the compound. The molar mass is used to convert between mass and moles.
- Convert the mass of each reactant to moles:
- Once you have the molar mass of each reactant, you can convert the given mass of each reactant (usually in grams) to moles using the formula:
[
\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}
]
This allows you to work with moles, the unit required for stoichiometric calculations.
- Use the stoichiometry of the balanced equation to find the moles of the product:
- From the balanced equation, determine the mole ratio between the reactants and the product(s). Using this ratio, you can convert moles of each reactant to moles of the product. For example, if the equation shows a 1:2 ratio of reactant A to product P, the number of moles of product P is twice the number of moles of reactant A used.
- Compare the moles of the product obtained from each reactant and identify the limiting reactant:
- After calculating the moles of product for each reactant, compare the results. The limiting reactant is the one that produces the least amount of product. This reactant runs out first and determines the amount of product formed. The other reactant is in excess and will not be fully consumed.
Explanation:
Stoichiometry is based on the concept that chemical reactions occur in definite proportions. The limiting reactant plays a critical role in determining how much product will be formed. By solving for the limiting reactant first, you ensure that you’re working with the reactant that will run out first. This method involves using the mole ratios from the balanced equation to connect the amounts of reactants to the products, ensuring accurate predictions of the reaction’s outcome. In many real-world scenarios, identifying the limiting reactant is crucial for optimizing reactions in industrial settings, lab experiments, and other applications.