Question

In a process for producing acetic acid, oxygen gas is bubbled into acetaldehyde, CH3CHO, containing manganese(II) acetate (catalyst) under pressure at 60°C. 2CH3CHO(l) + O2(g) → 2HC2H3O2(l) In a laboratory test of this reaction, 22.2 g CH3CHO and 12.6 g O2 were put into a reaction vessel. We wish to predict the following: a) How many grams of acetic acid can be produced by this reaction from these amounts of reactants?

Answer 1

Answer: The mass of acetic acid that can be produced is 30.24 grams

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$     .....(1)

• For acetaldehyde:

Given mass of acetaldehyde = 22.2 g

Molar mass of acetaldehyde = 44 g/mol

Putting values in equation 1, we get:

$\text{Moles of acetaldehyde}=\frac{22.2g}{44g/mol}=0.504mol$

• For oxygen gas:

Given mass of oxygen  gas = 12.6 g

Molar mass of oxygen gas = 32 g/mol

Putting values in equation 1, we get:

$\text{Moles of oxygen gas}=\frac{12.6g}{32g/mol}=0.394mol$

The given chemical equation follows:

$2CH_3CHO(l)+O_2(g)\rightarrow 2CH_3COOH(l)$

By Stoichiometry of the reaction:

2 moles of acetaldehyde reacts with 1 mole of oxygen gas

So, 0.504 moles of acetaldehyde will react with = $\frac{1}{2}\times 0.504=0.252mol$ of oxygen gas

As, given amount of oxygen gas is more than the required amount. So, it is considered as an excess reagent.

Thus, acetaldehyde is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

2 moles of acetaldehyde produces 2 moles of acetic acid

So, 0.504 moles of acetaldehyde will produce = $\frac{2}{2}\times 0.504=0.504moles$ of acetic acid

Now, calculating the mass of acetic acid from equation 1, we get:

Molar mass of acetic acid = 60 g/mol

Moles of acetic acid = 0.504 moles

Putting values in equation 1, we get:

$0.504mol=\frac{\text{Mass of acetic acid}}{60g/mol}\\\\\text{Mass of acetic acid}=(0.504mol\times 60g/mol)=30.24g$

Hence, the mass of acetic acid that can be produced is 30.24 grams