Question

A student is trying to figure out how many moles of potassium chloride are formed from 4.0 grams of chlorine gas. Which step in the following students work is incorrect?

Answer 1

Answer:

Step 3 ⇒ incorrect

Further explanation:

Given

mass of Cl₂ : 4 g

Required

incorrect step

Analysis

analyze step

• balanced equation

• determine mol of Cl₂
• mol ratio from equation
• potassium chloride formed

Solution

• balanced equation

Reaction

2K(s)+Cl₂(g)⇒2KCl(s)

Step 1⇒correct

• determine mol of Cl₂

we determine the moles of Cl₂ by their mass

MW of Cl₂=70.9 g/mol

mol=mass : MW

Step 2 ⇒ correct

• mol ratio from equation

From equation, mol ratio of Cl₂ to KCl = 1 : 2, so mol KCl :

$\tt mol~KCl=\dfrac{2}{1}\times 0.0564=0.1128$

Step 3 ⇒ incorrect

Paraphrase

Step 3 ⇒ incorrect