Which equation shows how to calculate how many grams $(g)$ of KCl would be produced from 4 mol KOH? The balanced reaction is:
$MgCl_2+2 KOH \rightarrow Mg(OH)_2+2 KCl$
A. $\frac{4 mol KOH }{1} \times \frac{1 mol KCl }{2 mol KOH } \times \frac{74.55 g KCl }{1 mol KCl }$
B. $\frac{4 mol KOH }{1} \times \frac{2 mol KCl }{1 mol KOH } \times \frac{74.55 g KCl }{1 mol KCl }$
C. $\frac{4 mol KOH }{1} \times \frac{2 mol KCl }{2 mol KOH } \times \frac{74.55 g KCl }{1 mol KCl }$
D. $\frac{4 mol KOH }{1} \times \frac{1 mol KOH }{1 mol KCl } \times \frac{74.55 g KCl }{1 mol KCl }$

Use the balanced chemical equation to determine the mole ratio between K O H and K Cl .
Multiply the given moles of K O H by the mole ratio to find the moles of K Cl produced.
Multiply the moles of K Cl by its molar mass to find the mass of K Cl produced.
Identify the equation that matches the correct calculation: C ​ .

Explanation

Problem Analysis We are given a balanced chemical reaction and asked to find the equation that correctly calculates the mass of K Cl produced from a given amount of K O H . The balanced reaction is: M g C l 2 ​ + 2 K O H → M g ( O H ) 2 ​ + 2 K Cl We are starting with 4 moles of K O H .

Mole Ratio From the balanced equation, we can see that 2 moles of K O H produce 2 moles of K Cl . This means the mole ratio of K Cl to K O H is 2 mol K O H 2 mol K Cl ​ , which simplifies to 1 mol K O H 1 mol K Cl ​ .

Calculating Mass of KCl To find the mass of K Cl produced, we need to multiply the moles of K O H by the mole ratio and then by the molar mass of K Cl . The molar mass of K Cl is given as 74.55 g/mol. So, the calculation should be: 4 mol K O H × 2 mol K O H 2 mol K Cl ​ × 1 mol K Cl 74.55 g K Cl ​ This simplifies to: 4 mol K O H × 1 mol K O H 1 mol K Cl ​ × 1 mol K Cl 74.55 g K Cl ​ = 4 × 74.55 g K Cl = 298.2 g K Cl

Comparing with Options Now, let's compare our calculation with the given options: Option A: 1 4 m o l K O H ​ × 2 m o l K O H 1 m o l K Cl ​ × 1 m o l K Cl 74.55 g K Cl ​ = 149.1 g K Cl (Incorrect) Option B: 1 4 m o l K O H ​ × 1 m o l K O H 2 m o l K Cl ​ × 1 m o l K Cl 74.55 g K Cl ​ = 596.4 g K Cl (Incorrect) Option C: 1 4 m o l K O H ​ × 2 m o l K O H 2 m o l K Cl ​ × 1 m o l K Cl 74.55 g K Cl ​ = 298.2 g K Cl (Correct) Option D: 1 4 m o l K O H ​ × 1 m o l K Cl 1 m o l K O H ​ × 1 m o l K Cl 74.55 g K Cl ​ (Incorrect - the mole ratio is inverted)

Final Answer The correct equation is: 1 4 m o l K O H ​ × 2 m o l K O H 2 m o l K Cl ​ × 1 m o l K Cl 74.55 g K Cl ​


Examples
Stoichiometry, the study of the quantitative relationships between reactants and products in chemical reactions, is crucial in many real-world applications. For instance, in pharmaceutical manufacturing, precise calculations are needed to determine the exact amounts of reactants required to produce a specific quantity of a drug. Similarly, in environmental science, stoichiometry is used to calculate the amount of a pollutant produced by a chemical reaction, helping to develop strategies for pollution control. In cooking, while not always explicitly stated, recipes rely on stoichiometric relationships to ensure the correct proportions of ingredients for a desired outcome. Understanding stoichiometry allows for efficient resource management and accurate predictions in various fields.

Answered by GinnyAnswer | 2025-07-07

The correct equation to calculate the grams of KCl produced from 4 moles of KOH, based on the balanced reaction, is Option C: 1 4 mol KOH ​ × 2 mol KOH 2 mol KCl ​ × 1 mol KCl 74.55 g KCl ​ . This calculation leads to 298.2 g of KCl produced.
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Answered by Anonymous | 2025-07-23