The Balanced Chemical Equation
The reaction you've provided is:
MgCl₂ + 2KOH → Mg(OH)₂ + 2KCl
This equation tells us:
* 1 mole of MgCl₂ reacts with 2 moles of KOH
* This produces 1 mole of Mg(OH)₂ and 2 moles of KCl
Determining the Limiting Reactant
To figure out how much product is made, we need to identify the limiting reactant. This is the reactant that gets used up first and therefore limits the amount of product that can be formed.
1. Moles of MgCl₂: You mentioned 3 moles of MgCl₂ are added.
2. Moles of KOH: You mentioned 4 moles of KOH are added.
3. Mole Ratio: From the balanced equation, we know 1 mole of MgCl₂ reacts with 2 moles of KOH.
4. Comparing:
* 3 moles of MgCl₂ would require 3 moles * 2 = 6 moles of KOH to react completely.
* Since we only have 4 moles of KOH, KOH is the limiting reactant.
Calculating the Amount of Product
Since KOH is the limiting reactant, we use its amount to determine how much product is formed.
1. Mg(OH)₂: The balanced equation shows a 2:1 ratio between KOH and Mg(OH)₂ (2 moles KOH produce 1 mole Mg(OH)₂).
* With 4 moles of KOH, we can produce 4 moles / 2 = 2 moles of Mg(OH)₂.
2. KCl: The balanced equation shows a 2:2 ratio between KOH and KCl (2 moles KOH produce 2 moles KCl).
* With 4 moles of KOH, we can produce 4 moles * (2/2) = 4 moles of KCl.
In Summary
In this reaction with 3 moles of MgCl₂ and 4 moles of KOH, KOH is the limiting reactant. This means we can produce:
* 2 moles of Mg(OH)₂
* 4 moles of KCl
