Question

The odor of skunks is caused by chemical compounds called thiols. These compounds, of which butanethiol \(\left(\mathrm{C}_{4} \mathrm{H}_{10} \mathrm{~S}\right)\) is a representative example, can be deodorized by reaction with household bleach (NaOCl) according to the following equation: \(2 \mathrm{C}_{4} \mathrm{H}_{10} \mathrm{~S}(l)+\mathrm{NaOCl}(a q) \longrightarrow \mathrm{C}_{s} \mathrm{H}_{18} \mathrm{~S}_{2}(l)+\mathrm{NaCl}(a q)+\mathrm{H}_{2} \mathrm{O}(l)\) How many grams of butanethiol can be deodorized by reaction with \(5.00 \mathrm{~mL}\) of \(0.0985 \mathrm{M} \mathrm{NaOCl} ?\)

Short answer

0.0888 grams of butanethiol can be deodorized.

Step-by-step solution

Calculate Moles of NaOCl

To find out how much butanethiol can be deodorized, we first need to calculate the moles of NaOCl available. We have a volume of 5.00 mL (which is 0.005 L) and a concentration of 0.0985 M. The moles of NaOCl are calculated using the formula: \[ \text{moles of NaOCl} = \text{volume} \times \text{concentration} = 0.005 \times 0.0985 = 0.0004925 \text{ moles} \]

Use Stoichiometry to Determine Moles of Butanethiol

According to the balanced equation, 1 mole of NaOCl reacts with 2 moles of butanethiol \((\text{C}_4\text{H}_{10}\text{S})\). Using stoichiometry, we find the moles of butanethiol:\[ \text{moles of butanethiol} = 2 \times \text{moles of NaOCl} = 2 \times 0.0004925 = 0.000985 \text{ moles} \]

Calculate Mass of Butanethiol

To find the mass of butanethiol corresponding to the calculated moles, we need the molar mass of butanethiol. The molar mass of \( \text{C}_4 \text{H}_{10} \text{S} \) is calculated as follows: - Carbon (C): 12.01 g/mol, 4 atoms - Hydrogen (H): 1.01 g/mol, 10 atoms - Sulfur (S): 32.07 g/mol, 1 atom The molar mass of butanethiol is:\[ (4 \times 12.01) + (10 \times 1.01) + (32.07) = 90.19 \text{ g/mol} \]Now, calculate the mass:\[ \text{mass} = \text{moles} \times \text{molar mass} = 0.000985 \times 90.19 = 0.0888 \text{ g} \]

Key concepts

Chemical Reactions

Chemical reactions occur when substances, called reactants, are transformed into different substances, called products. In the context of thiols and household bleach, a fascinating chemical reaction occurs. Thiols, such as butanethiol, are known for their strong and often unpleasant smells. This reaction involves butanethiol reacting with sodium hypochlorite (NaOCl), a common component in bleach. This transformation changes the chemical composition of butanethiol, thus eliminating its odor.
The balanced chemical equation for this reaction is: \[2 \text{C}_4\text{H}_{10}\text{S} + \text{NaOCl} \rightarrow \text{C}_8\text{H}_{18}\text{S}_2 + \text{NaCl} + \text{H}_2\text{O}\]

• Reactants: Butanethiol (\(\text{C}_4\text{H}_{10}\text{S}\)) and Sodium hypochlorite (\(\text{NaOCl}\))
• Products: A disulfide compound (\(\text{C}_8\text{H}_{18}\text{S}_2\)), Sodium chloride (\(\text{NaCl}\)), and Water (\(\text{H}_2\text{O}\))

This reaction is made possible through stoichiometry, which allows us to calculate the amount of reactants needed to produce a certain amount of product efficiently.

Molar Mass

Understanding molar mass is crucial when performing chemical calculations. Molar mass is the mass of one mole of a substance and is expressed in grams per mole (g/mol). With the help of the molar mass, you can convert between the mass of a substance and the number of moles to participate in a reaction.
To compute the molar mass of butanethiol \((\text{C}_4\text{H}_{10}\text{S})\):

• Carbon (C): 12.01 g/mol and there are 4 Carbon atoms, thus \(4 \times 12.01 = 48.04\) g/mol
• Hydrogen (H): 1.01 g/mol and there are 10 Hydrogen atoms, thus \(10 \times 1.01 = 10.10\) g/mol
• Sulfur (S): 32.07 g/mol and there is 1 Sulfur atom, hence its contribution remains \(32.07\) g/mol

The total molar mass of butanethiol is calculated as: \[ 48.04 + 10.10 + 32.07 = 90.19 \text{ g/mol}\]
This value allows us to find out how much butanethiol is involved in a chemical reaction by converting moles of butanethiol to grams.

Thiols

Thiols, also known as mercaptans, are a class of sulfur-containing organic compounds characterized by the presence of a sulfhydryl group \((-\text{SH})\). They are known for their strong and often unpleasant odors, which is why they are commonly associated with the smell of skunks.
Thiols are important in various applications:

• Agriculture: Used as soil fumigants.
• Industrials: Serving as an additive for anti-corrosion, especially in the petroleum industry.
• Biological: Plays a role in the structure of proteins through the formation of disulfide bonds.

The reaction of thiols with bleach in deodorizing processes is particularly significant. When butanethiol is mixed with \(\text{NaOCl}\), the thiol component is oxidized to form a disulfide bond, transforming it into a less odorous compound. This is the principle used in household deodorizing products where an unpleasant smell is chemically neutralized.