Stoikiometri (6) | Pereaksi Pembatas | Kimia Kelas 10

Introduction

This tutorial will guide you through the process of determining the limiting reactant (pereaksi pembatas) in stoichiometry, a key concept in chemistry for Grade 10 students. Understanding how to identify the limiting reactant is essential for predicting the outcomes of chemical reactions and optimizing reactant usage.

Step 1: Understand Stoichiometry

• Stoichiometry involves calculating the relationships between reactants and products in a chemical reaction.
• It is based on the conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction.

Step 2: Identify the Chemical Equation

• Write down the balanced chemical equation for the reaction you are analyzing.
• Example: For the reaction of hydrogen and oxygen to form water:

  2 H₂ + O₂ → 2 H₂O
  

Step 3: Determine the Moles of Reactants

• Calculate the number of moles for each reactant using the formula:

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

• Ensure you have the mass of each reactant and their respective molar masses.

Step 4: Use Stoichiometric Ratios

• From the balanced equation, identify the stoichiometric ratios between the reactants.
• For the example above, the ratio of hydrogen to oxygen is 2:1.

Step 5: Calculate Required Moles of Each Reactant

• Based on the moles of one reactant, calculate how many moles of the other reactant are needed for the reaction to proceed.
• Example: If you have 3 moles of H₂, you would need:

  Required O₂ = (3 moles H₂) * (1 mole O₂ / 2 moles H₂) = 1.5 moles O₂
  

Step 6: Compare Available Moles with Required Moles

• Compare the actual available moles of each reactant to the required moles calculated in the previous step.
• Identify which reactant is in insufficient quantity to fully react.

Step 7: Identify the Limiting Reactant

• The reactant that runs out first (the one that is less than the required amount) is the limiting reactant.
• Example: If you have 1 mole of O₂ available but need 1.5 moles, O₂ is the limiting reactant.

Conclusion

In this tutorial, you learned how to determine the limiting reactant in a chemical reaction through a series of systematic steps. By understanding stoichiometry, identifying chemical equations, calculating moles, and comparing available and required amounts, you can effectively analyze any reaction. As a next step, practice with different chemical reactions to reinforce your understanding of this important concept in chemistry.