Question

Which has a higher percentage of fluorine: Freon-12 \(\left(\mathrm{CCl}_{2} \mathrm{~F}_{2}\right)\) or Freon \(113\left(\mathrm{C}_{2} \mathrm{Cl}_{3} \mathrm{~F}_{3}\right) ?\)

Short answer

Freon-12 has the higher percentage of fluorine compared to Freon-113.

Step-by-step solution

Calculate Molecular Weights

First, determine the molecular weight of both Freon-12 and Freon-113 compounds by adding the atomic weights of each element within the molecule. For Freon-12: Molecular weight of C (12) times 1, Cl (35.5) times 2, and F (19) times 2. For Freon-113: Weight of C (12) times 2, Cl (35.5) times 3, and F (19) times 3.

Calculate Weight of Fluorine in Each Compound

Find the total weight of fluorine in each compound. In Freon-12, multiply the atomic weight of fluorine (19) by the number of fluorine atoms (2). In Freon-113, multiply the atomic weight of fluorine (19) by the number of fluorine atoms (3).

Determine Percentage of Fluorine

Calculate the percentage of fluorine in each compound by dividing the weight of fluorine by the total molecular weight of the compound, and then multiplying by 100 to convert to a percentage. Do this for both Freon-12 and Freon-113.

Compare Percentages

With the percentage of fluorine calculated for both compounds, compare the values to see which compound has the higher percentage of fluorine.

Key concepts

Percentage Composition

The percentage composition of a compound is a critical concept in chemistry that represents the percent by mass of each element within a compound. It is calculated by dividing the mass of a specific element in one mole of the compound by the total molar mass of the compound, and then multiplying the result by 100 to obtain a percentage. Understanding the percentage composition is essential for various applications including determining the formula of an unknown compound and analyzing chemical reactions.

Let's apply this to our exercise where we compare the percentage of fluorine in Freon-12 and Freon-113. By following the steps outlined in the solution, you calculate the mass of fluorine in each compound and divide by the molecular weight of the entire compound. This gives you the fluorine's share in each compound's total mass, which is the essence of percentage composition. It's a straightforward yet powerful way to discern which compound contains more fluorine relative to its overall mass.

Chemical Formulas

Chemical formulas are essential tools used to convey a lot of information about a substance in a very succinct package. They tell us the types of atoms present in a compound and in what ratios they combine. There are different types of chemical formulas, such as empirical formulas that show the simplest whole-number ratio of elements in a compound and molecular formulas that provide the actual number of atoms of each element in a molecule.

In our exercise, Freon-12 and Freon-113 are represented by their molecular formulas, CCl2F2 and C2Cl3F3, respectively. These formulas are key to understanding the makeup of these compounds and are the starting point for the molecular weight and percentage composition calculations. By breaking down these formulas, we can see that Freon-113 has a higher number of fluorine atoms than Freon-12, which might suggest a higher percentage of fluorine by mass - but only a calculation can confirm this.

Atomic Weight

Atomic weight is the average mass of atoms of an element, measured in atomic mass units (amu). It's averaged because a natural sample of an element contains a mix of isotopes, each with its own atomic mass. On the periodic table, the atomic weight is listed under the symbol of each element, and it's a fundamental property used in countless calculations in chemistry.

In the context of the given exercise, you need to know the atomic weights of carbon (C), chlorine (Cl), and fluorine (F) to calculate the molecular weights of Freon-12 and Freon-113. For example, the atomic weight of fluorine (19 amu) is multiplied by the number of fluorine atoms in the compound to find the total weight contributed by fluorine. By using the atomic weights, you can calculate the molecular weight of the entire compound, which is the sum of the weights of all atoms present in the molecule.