Question

For many years, chloroform ( \(\mathrm{CHCl}_{3}\) ) was used as an inhalation anesthetic in spite of the fact that it is also a toxic substance that may cause severe liver, kidney, and heart damage. Calculate the percent composition by mass of this compound.

Short answer

Chloroform is 10.06% Carbon, 0.85% Hydrogen, and 89.09% Chlorine by mass.

Step-by-step solution

Find the Molar Mass of Each Element

First, let's identify the elements in chloroform: Carbon (C), Hydrogen (H), and Chlorine (Cl). We will find the molar mass of each element. - Carbon (C) has a molar mass of approximately 12.01 g/mol. - Hydrogen (H) has a molar mass of approximately 1.01 g/mol. - Chlorine (Cl) has a molar mass of approximately 35.45 g/mol.

Determine the Molar Mass of \\( \mathrm{CHCl}_{3} \\\)

Chloroform consists of 1 carbon atom, 1 hydrogen atom, and 3 chlorine atoms. So, we calculate the molar mass by adding their individual masses:\[\text{Molar mass of } \mathrm{CHCl}_{3} = 1(12.01) + 1(1.01) + 3(35.45) = 119.38 \text{ g/mol}\]

Calculate the Mass Percent of Carbon

The mass percent of an element is found by dividing the element's total mass in the molecule by the molar mass of the whole compound, then multiplying by 100 to convert to a percentage.\[\text{Percent of Carbon} = \left( \frac{12.01}{119.38} \right) \times 100 \approx 10.06\%\]

Calculate the Mass Percent of Hydrogen

Similarly, find the mass percent of hydrogen by using its mass and the total molar mass of chloroform.\[\text{Percent of Hydrogen} = \left( \frac{1.01}{119.38} \right) \times 100 \approx 0.85\%\]

Calculate the Mass Percent of Chlorine

Finally, calculate the mass percent of chlorine (3 atoms) and divide by the molar mass of chloroform.\[\text{Percent of Chlorine} = \left( \frac{3 \times 35.45}{119.38} \right) \times 100 \approx 89.09\%\]

Key concepts

Molar Mass

Understanding molar mass is crucial when studying chemical compounds. Molar mass represents the mass of one mole of a given chemical element or compound. It is usually expressed in grams per mole (g/mol). This measure helps chemists to predict how a substance participates in reactions and its quantitative properties.
To calculate molar mass:

• Identify each element in the compound and its atomic mass (from the periodic table).
• Multiply the atomic mass of each element by the number of atoms of that element in the compound.
• Sum these values for all elements to obtain the total molar mass.

For instance, in chloroform (\( \mathrm{CHCl}_3 \)), the molar mass is calculated by adding the masses of one carbon atom, one hydrogen atom, and three chlorine atoms, resulting in a molar mass of 119.38 g/mol. This calculation is straightforward but fundamental in many chemical operations.

Chloroform

Chloroform, chemically known as \( \mathrm{CHCl}_3 \), is an organic compound with one carbon atom, one hydrogen atom, and three chlorine atoms. Historically, it was used as an anesthetic, but due to its toxicity, its use has declined considerably. Understanding its structure helps in grasping how it behaves and interacts with other substances.
Chloroform's molecular composition highlights a few important points:

• It has a simple structure, yet the presence of chlorine makes it reactive and potentially harmful.
• The combined weight of the elements contributes to its relatively high molar mass compared to simpler compounds.
When calculating the percent composition, each element's contribution is crucial since chlorine dominates the structure, impacting its properties and applications.

Mass Percent

Mass percent, also known as percent composition by mass, helps determine what portion of a compound's total mass comes from each element. It is a way to express a compound's composition with respect to weight.
To find the mass percent:

• Take the mass of the specific element within one mole of the compound.
• Divide this by the total molar mass of the compound.
• Multiply by 100 to convert the ratio to a percentage.

For example, in chloroform (\( \mathrm{CHCl}_3 \)), you'll find:

• Carbon contributes about 10.06% to the total mass.
• Hydrogen adds approximately 0.85%.
• Chlorine dominates with around 89.09%.

These percentages provide insight into the composition and can affect the substance's chemical behavior and physical properties. Mass percent is an essential concept not only in lab calculations but also in understanding the chemical nature of substances.