Question

When \(10.0 \mathrm{~g}\) of n-propylchloride is allowed to react with excess sodium in the Wurtz reaction, how many grams of hexane would be produced assuming a \(70 \%\) yield?

Short answer

The amount of hexane produced in the Wurtz reaction with a 70% yield is approximately 3.837 grams.

Step-by-step solution

1. Find the molar mass of n-propylchloride

First, we need to determine the molar mass of n-propylchloride, which has the molecular formula C3H7Cl. The molar masses of each element are: - Carbon (C): 12.01 g/mol - Hydrogen (H): 1.01 g/mol - Chlorine (Cl): 35.45 g/mol Now, we can calculate the molar mass of n-propylchloride: Molar mass of n-propylchloride = (3 x 12.01) + (7 x 1.01) + 35.45 = 78.54 g/mol

2. Calculate the moles of n-propylchloride reacted

Given 10.0 g of n-propylchloride, we can find the moles by dividing the mass by the molar mass: Moles of n-propylchloride = (10.0 g) / (78.54 g/mol) = 0.1273 mol

3. Use stoichiometry to determine the moles of hexane produced

In the Wurtz reaction, two moles of n-propylchloride react to produce one mole of hexane. Therefore, the ratio between the moles of n-propylchloride and moles of hexane is 2:1. By using this stoichiometric ratio, we can calculate the moles of hexane produced: Moles of hexane = (0.1273 mol of n-propylchloride) * (1 mol of hexane / 2 mol of n-propylchloride) = 0.06365 mol of hexane

4. Calculate the molar mass of hexane

Hexane has the molecular formula C6H14. The molar masses of each element are: - Carbon (C): 12.01 g/mol - Hydrogen (H): 1.01 g/mol Now, we can calculate the molar mass of hexane: Molar mass of hexane = (6 x 12.01) + (14 x 1.01) = 86.18 g/mol

5. Determine the mass of hexane produced

To find the mass of hexane produced, multiply the number of moles of hexane by its molar mass: Mass of hexane = (0.06365 mol of hexane) * (86.18 g/mol) = 5.481 g of hexane

6. Adjust for the actual yield of the reaction

The problem states that the yield of the reaction is 70%. To find the actual mass of hexane produced, we need to multiply the theoretical mass of hexane by the actual yield: Mass of hexane (actual) = (5.481 g) * (70%) = 3.837 g So, the amount of hexane produced in this reaction with a 70% yield is approximately 3.837 g.

Key concepts

n-Propylchloride

N-propylchloride, also known as 1-chloropropane, is an organic compound with a chemical formula of C\(_3\)H\(_7\)Cl. This compound is part of the alkyl halides group, which are alkanes with one hydrogen atom replaced by a halogen atom. In this case, an atom of chlorine takes the place of a hydrogen atom.

Its molecular structure consists of a three-carbon chain, with chlorine bonded to the first carbon, making it a primary chloroalkane. This structure gives n-propylchloride specific reactivity, making it suitable for various chemical reactions, including the Wurtz reaction.

Key properties of n-propylchloride include:

• Colorless liquid
• Boiling point: about 46°C
• Soluble in organic solvents
• Slightly soluble in water

Understanding n-propylchloride is essential when dealing with chemical reactions like the Wurtz reaction, as it helps predict product outcomes and yields.

Hexane

Hexane is a simple alkane with the molecular formula C\(_6\)H\(_{14}\). It consists of six carbon atoms connected by single bonds, with each carbon atom bonded to hydrogen atoms until the maximum number of bonds are reached. This establishes it as a saturated hydrocarbon.

Hexane is known for being a major component of gasoline and is commonly used as a non-polar solvent in laboratories and industries. It exists as a colorless, liquid, and is known for its relatively low boiling point of about 69°C.

Key characteristics of hexane include:

• Low chemical reactivity
• Good solvent properties for dissolving oils and greases
• Presents in mixtures like petroleum ether

In the context of the Wurtz reaction, hexane is typically the product when alkyl halides such as n-propylchloride react with sodium metal. Understanding its properties is crucial to manipulate reaction conditions and predict product availability effectively.

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the relationship between the quantities of reactants and products in chemical reactions. It allows scientists to calculate the exact amounts of substances needed or produced in a reaction.

In this exercise, stoichiometry guides us through the Wurtz reaction between n-propylchloride and sodium. The balanced chemical equation shows that two moles of n-propylchloride produce one mole of hexane. This is a 2:1 molar ratio between reactant and product.

Steps in stoichiometric calculations often include:

• Finding molar masses of reactants and products
• Converting masses into moles
• Using reaction ratios to find products

Stoichiometry is essential not only for predicting the amount of products formed like hexane but also for optimizing resource use in chemical processes.

Reaction Yield

Reaction yield is an important measure in chemistry that reflects the efficiency of a chemical reaction. It compares the actual amount of product obtained to the amount theoretically calculated, usually expressed as a percentage.

In our example, the theoretical yield of hexane was calculated as about 5.481 grams, assuming perfect reaction conditions and no losses.

However, the actual yield was adjusted to a practical 70% based on experimental data or known efficiency limits, which resulted in 3.837 grams of hexane.

Factors influencing reaction yield include:

• Purity of reactants
• Reaction conditions such as temperature and pressure
• Side reactions that may occur during the process

Understanding factors that affect reaction yield is crucial for chemical manufacturing and laboratory work, where efficiency and costs are closely monitored. An accurate prediction of reaction yield helps in setting realistic expectations and improving chemical process design.