Question

Mustard gas \(\left(\mathrm{C}_{4} \mathrm{H}_{8} \mathrm{Cl}_{2} \mathrm{~S}\right)\) is a poisonous gas that was used in World War I and banned afterward. It causes general destruction of body tissues, resulting in the formation of large water blisters. There is no effective antidote. Calculate the percent composition by mass of the elements in mustard gas.

Short answer

Mustard gas percent composition: C: 30.20%, H: 5.08%, Cl: 44.55%, S: 20.17%.

Step-by-step solution

Find Molar Mass of Each Element

First, determine the molar mass of each element in mustard gas (C_4H_8Cl_2S):- Carbon (C): 12.01 g/mol- Hydrogen (H): 1.01 g/mol- Chlorine (Cl): 35.45 g/mol- Sulfur (S): 32.07 g/mol.Multiply each by the number of atoms of that element in the compound.- Carbon: \( 4 \times 12.01 = 48.04 \, \text{g/mol} \)- Hydrogen: \( 8 \times 1.01 = 8.08 \, \text{g/mol} \)- Chlorine: \( 2 \times 35.45 = 70.90 \, \text{g/mol} \)- Sulfur: \( 1 \times 32.07 = 32.07 \, \text{g/mol} \).

Calculate Total Molar Mass of Compound

Add together the molar masses of all the elements to find the total molar mass of mustard gas:\[ 48.04 + 8.08 + 70.90 + 32.07 = 159.09 \, \text{g/mol} \].

Calculate Percent Composition for Each Element

For each element, divide its total mass by the total molar mass of the compound and multiply by 100 to find the percent composition:- Percent Carbon: \[ \left(\frac{48.04}{159.09}\right) \times 100 = 30.20\% \]- Percent Hydrogen:\[ \left(\frac{8.08}{159.09}\right) \times 100 = 5.08\% \]- Percent Chlorine:\[ \left(\frac{70.90}{159.09}\right) \times 100 = 44.55\% \]- Percent Sulfur:\[ \left(\frac{32.07}{159.09}\right) \times 100 = 20.17\% \].

Key concepts

Understanding Molar Mass

Molar mass is the mass of one mole of a substance, measured in grams per mole (g/mol). It's like weighing a dozen eggs to find how much a dozen weigh based on the weight of one egg. Knowing the molar mass of a compound helps us understand how much of each element is present. Here's how it works in mustard gas (\(\text{C}_4\text{H}_8\text{Cl}_2\text{S}\)):

• Start by finding the molar mass of each individual element, such as carbon (C = 12.01 g/mol).
• Multiply by the number of each atom in the compound (e.g., 4 carbon atoms: \(4 \times 12.01 = 48.04 \, \text{g/mol}\)).
• Add together all the individual molar masses to reach the total molar mass: \(159.09 \, \text{g/mol}\) for mustard gas.

Mastering molar mass calculations is essential for chemistry, enabling us to explore properties of different substances.

A Closer Look at Mustard Gas

Mustard gas, with the chemical formula \(\text{C}_4\text{H}_8\text{Cl}_2\text{S}\), played a horrific role in World War I. It's notorious for causing severe blistering of the skin and internal tissues, leading to it being banned in warfare.

• Why was it named 'mustard'? Its scent resembles mustard plants, but its effects are anything but mild.
• There's no known antidote, making it a terrifying poison at the time of use.
• Understanding its composition provides insight into why it affects humans so terribly, primarily through the element sulfur, which leads to tissue damage.

The story of mustard gas is a warning of chemical warfare's dangers and the importance of chemical regulation.

Elemental Analysis Explained

Elemental analysis refers to understanding the exact composition of a compound by determining the percentage of each element within it. This is crucial for chemists who need to know the makeup of a substance, whether it's to develop new drugs or understand existing compounds. Here's how it's done with mustard gas:

• Calculate the molar mass of each element in the compound.
• Divide the mass of each element by the total molar mass of the compound to find its percentage composition.
• For example, carbon's percentage in mustard gas is determined through \(\frac{48.04}{159.09} \times 100 = 30.20\%\).

This method helps chemists assess and manipulate chemical behavior, ensuring precise measurements for various applications.