Final answer:
The elements in the compound CF₂Cl₂ in order of decreasing mass percent composition are Chlorine (Cl), Fluorine (F), and Carbon (C), with Chlorine having the highest mass percent. Hence, the correct answer is D.
Step-by-step explanation:
To determine the order of elements in the compound CF₂Cl₂ by their mass percent composition, we first need to calculate the molar mass of each element multiplied by the number of atoms of that element present in the compound. The compound contains one carbon atom (C), two fluorine atoms (F), and two chlorine atoms (Cl). Now let's calculate the molar masses:
- C: 12.01 g/mol
- F: 19.00 g/mol × 2 = 38.00 g/mol
- Cl: 35.45 g/mol × 2 = 70.90 g/mol
Adding these up gives us the molar mass of CF₂Cl₂:
12.01 g/mol (C) + 38.00 g/mol (F) + 70.90 g/mol (Cl) = 120.91 g/mol
To find the mass percent of each element, divide the element's molar mass by the total molar mass of the compound and multiply by 100%:
- C: (12.01 g/mol / 120.91 g/mol) × 100% ≈ 9.93%
- F: (38.00 g/mol / 120.91 g/mol) × 100% ≈ 31.43%
- Cl: (70.90 g/mol / 120.91 g/mol) × 100% ≈ 58.64%
Comparing these percentages:
Cl > F > C
Therefore, the elements in the compound CF₂Cl₂ in order of decreasing mass percent composition are Chlorine (Cl), Fluorine (F), and Carbon (C), making the correct answer (d) Cl > F > C.