Question

a 12.50 g sample containing chlorine and oxygen is found to have the composition given below. imagine that we now have a 100.0 gram sample. how many moles of each element would be present in the imaginary 100.0 gram sample?

element
% composition
mass of element in 100.0 grams of sample:
molar mass of element
moles of element

cl
38.76%
38.76 g
35.45 g/mol

o
61.24%
61.24 g
16.00 g/mol

Explanation:

Step1: Calculate moles of Cl

Use formula \(n=\frac{m}{M}\), where \(n\) is moles, \(m\) is mass, \(M\) is molar mass.
For Cl: \(m = 38.76g\), \(M=35.45g/mol\)
\(n_{Cl}=\frac{38.76g}{35.45g/mol}\)

Step2: Calculate moles of O

For O: \(m = 61.24g\), \(M = 16.00g/mol\)
\(n_{O}=\frac{61.24g}{16.00g/mol}\)

Answer:

Moles of \(Cl\): \(\frac{38.76}{35.45}\approx1.093\) mol
Moles of \(O\): \(\frac{61.24}{16.00}=3.8275\) mol