Question

1. how many moles of alcl₃ are there in 400.5 grams of alcl₃?

0.34 moles
66.6 × 10²³ moles
6.45 moles
3.00 moles
clear all

Explanation:

Step1: Calculate molar mass of \(AlCl_3\)

Molar mass of \(Al = 27\space g/mol\), molar mass of \(Cl=35.5\space g/mol\).
Molar mass of \(AlCl_3=27 + 3\times35.5=27 + 106.5 = 133.5\space g/mol\)

Step2: Use formula \(n=\frac{m}{M}\)

Given \(m = 400.5\space g\), \(M = 133.5\space g/mol\)
\(n=\frac{400.5}{133.5}=3\space mol\)

Answer:

3.00 moles