4 molecules of ethylene (C2H4) react with 2 molecules of oxygen (O2) to produce some amount of acetaldehyde (C2H4O).

Question

Complete the table below.
Chemical element Number of atoms in the reaction

During this reaction, how many molecules of acetaldehyde (C2H4O) are produced?

Answer 1

To balance the reaction of ethylene (C2H4) and oxygen (O2) to produce acetaldehyde (C2H4O), we can start by writing the unbalanced equation:

\[ 4 \text{ C}_2\text{H}_4 + 2 \text{ O}_2 \rightarrow x \text{ C}_2\text{H}_4\text{O} \]

Next, let's analyze the reactants:

1. Reactants:
   • Ethylene (C2H4): 4 molecules contain:
     • Carbon: \(4 \times 2 = 8\)
     • Hydrogen: \(4 \times 4 = 16\)
   • Oxygen (O2): 2 molecules contain:
     • Oxygen: \(2 \times 2 = 4\)

Now let’s tally the atoms in total for the reactants:

• Total Carbon: 8
• Total Hydrogen: 16
• Total Oxygen: 4

Now for the products, we have acetaldehyde (C2H4O). We should assume all carbon and oxygen is used to produce acetaldehyde. The general formula for balancing would let us define \(x\) as the molecules of acetaldehyde produced.

In terms of the atoms:

• Each molecule of acetaldehyde has:
  • Carbon: 2
  • Hydrogen: 4
  • Oxygen: 1

Thus, if \(x\) molecules of acetaldehyde are produced:

• Carbon: \(2x\)
• Hydrogen: \(4x\)
• Oxygen: \(x\)

Now we match the reactant totals to the product totals:

1. For Carbon: \[ 2x = 8 \implies x = 4 \]

2. For Hydrogen: \[ 4x = 16 \implies x = 4 \]

3. For Oxygen: \[ x = 4 \]

Since all equations give \(x = 4\), this indicates that 4 molecules of acetaldehyde are produced.

Summary:

So, the final balanced reaction is: \[ 4 \text{ C}_2\text{H}_4 + 2 \text{ O}_2 \rightarrow 4 \text{ C}_2\text{H}_4\text{O} \]

Fill in the table:

Chemical element | Number of atoms in the reaction --- | --- Carbon (C) | 8 Hydrogen (H) | 16 Oxygen (O) | 4

Final answer:

4 molecules of acetaldehyde (C2H4O) are produced.