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. $\frac{4 mol KOH }{1} \times \frac{1 mol KOH }{1 mol KCl } \times \frac{74.55 g KCl }{1 mol KCl }$
Answer (2)
Determine the mole ratio between KOH and KCl from the balanced equation.
Use the molar mass of KCl to convert moles of KCl to grams of KCl.
Set up the equation as: 4 mol KOH × 2 mol KOH 2 mol KCl × 1 mol KCl 74.55 g KCl
The correct equation is C: 1 4 mol KOH × 2 mol KOH 2 mol KCl × 1 mol KCl 74.55 g KCl
Explanation
Understanding the Problem The problem asks us to identify the correct equation to calculate the mass of KCl produced from 4 moles of KOH, given the balanced chemical reaction: M g C l 2 + 2 K O H → M g ( O H ) 2 + 2 K Cl . We need to use stoichiometry to convert moles of KOH to grams of KCl.
Determining the Mole Ratio First, we need to find the mole ratio between KOH and KCl from the balanced equation. The equation shows that 2 moles of KOH produce 2 moles of KCl. Therefore, the mole ratio is 2 mol KOH 2 mol KCl , which simplifies to 1 mol KOH 1 mol KCl .
Using the Molar Mass Next, we need to use the molar mass of KCl to convert moles of KCl to grams of KCl. The molar mass of KCl is given as 74.55 g/mol.
Setting up the Equation Now, we can set up the equation to convert 4 moles of KOH to grams of KCl. We start with 4 moles of KOH, multiply by the mole ratio, and then multiply by the molar mass of KCl: 4 mol KOH × 2 mol KOH 2 mol KCl × 1 mol KCl 74.55 g KCl This simplifies to: 4 mol KOH × 1 mol KOH 1 mol KCl × 1 mol KCl 74.55 g KCl
Identifying the Correct Option Comparing our equation to the given options, we see that option C matches our equation: 1 4 mol KOH × 2 mol KOH 2 mol KCl × 1 mol KCl 74.55 g KCl Option C is the correct equation.
Final Answer Therefore, the correct equation to calculate the grams of KCl produced from 4 mol KOH is: 1 4 mol KOH × 2 mol KOH 2 mol KCl × 1 mol KCl 74.55 g KCl
Examples
Stoichiometry is used in cooking to scale recipes. For example, if a recipe calls for 2 eggs and 1 cup of flour, and you only want to use 1 egg, you can use stoichiometry to determine that you need 0.5 cups of flour. Similarly, in chemical reactions, stoichiometry helps us determine the amount of reactants needed and the amount of products formed. This is crucial in industrial processes to optimize reactions and minimize waste, ensuring efficient production and resource utilization.
The correct equation to find out how many grams of KCl can be produced from 4 moles of KOH, based on the given balanced reaction, is option C: 1 4 mol KOH × 2 mol KOH 2 mol KCl × 1 mol KCl 74.55 g KCl . This takes into account the mole ratio from the balanced equation and the molar mass of KCl for conversion.
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