Question

how many grams of cl are in a 38.0-g sample of the chlorofluorocarbon cf₂cl₂? express your answers in grams of chlorine to three significant figures.
part e
how many grams of cl are in a 38.0-g sample of the chlorofluorocarbon cfcl₃? express your answer in grams of chlorine to three significant figures.

Explanation:

Step1: Calculate molar mass of CF₂Cl₂

Molar mass = C + 2F + 2Cl = 12.01 + 2×19.00 + 2×35.45 = 120.91 g/mol

Step2: Find mass fraction of Cl in CF₂Cl₂

Mass fraction = (2×35.45)/120.91 ≈ 0.586

Step3: Calculate Cl mass in CF₂Cl₂ sample

Cl mass = 38.0 g × 0.586 ≈ 22.3 g

Step4: Calculate molar mass of CFCl₃

Molar mass = C + F + 3Cl = 12.01 + 19.00 + 3×35.45 = 137.36 g/mol

Step5: Find mass fraction of Cl in CFCl₃

Mass fraction = (3×35.45)/137.36 ≈ 0.774

Step6: Calculate Cl mass in CFCl₃ sample

Cl mass = 38.0 g × 0.774 ≈ 29.4 g

Answer:

22.3 g
29.4 g