Question

ethanol is a chemical that is used in many hand sanitizers. it is produced when steam reacts with the chemical ethylene.
consider the following reaction:
3 molecules of ethylene (c₂h₄) react with 3 molecules of water (h₂o) to produce some amount of ethanol (c₂h₆o).
complete the table below.

chemical element	number of atoms in the reaction
c
o

during this reaction, how many molecules of ethanol (c₂h₆o) are produced?

Explanation:

Part 1: Completing the table for number of atoms

Step 1: Calculate number of H atoms

• Each ethylene ($\ce{C2H4}$) has 4 H atoms, 3 molecules: $3 \times 4 = 12$ H atoms.
• Each water ($\ce{H2O}$) has 2 H atoms, 3 molecules: $3 \times 2 = 6$ H atoms.
• Total H atoms: $12 + 6 = 18$.

Step 2: Calculate number of C atoms

• Each ethylene ($\ce{C2H4}$) has 2 C atoms, 3 molecules: $3 \times 2 = 6$ C atoms.

Step 3: Calculate number of O atoms

• Each water ($\ce{H2O}$) has 1 O atom, 3 molecules: $3 \times 1 = 3$ O atoms.

Part 2: Number of ethanol molecules produced

Step 1: Determine the balanced reaction

The reaction is: $3\ce{C2H4} + 3\ce{H2O}
ightarrow?\ce{C2H6O}$

• For C: 3 molecules of $\ce{C2H4}$ have $3 \times 2 = 6$ C atoms. Each $\ce{C2H6O}$ has 2 C atoms, so number of $\ce{C2H6O}$ molecules from C: $\frac{6}{2} = 3$.
• For H: 18 H atoms (from part 1), each $\ce{C2H6O}$ has 6 H atoms: $\frac{18}{6} = 3$.
• For O: 3 O atoms (from part 1), each $\ce{C2H6O}$ has 1 O atom: $\frac{3}{1} = 3$.

Final Answers

Table:

Chemical element	Number of atoms in the reaction
C	6
O	3

Number of ethanol molecules: 3

Answer:

Part 1: Completing the table for number of atoms

Step 1: Calculate number of H atoms

• Each ethylene ($\ce{C2H4}$) has 4 H atoms, 3 molecules: $3 \times 4 = 12$ H atoms.
• Each water ($\ce{H2O}$) has 2 H atoms, 3 molecules: $3 \times 2 = 6$ H atoms.
• Total H atoms: $12 + 6 = 18$.

Step 2: Calculate number of C atoms

• Each ethylene ($\ce{C2H4}$) has 2 C atoms, 3 molecules: $3 \times 2 = 6$ C atoms.

Step 3: Calculate number of O atoms

• Each water ($\ce{H2O}$) has 1 O atom, 3 molecules: $3 \times 1 = 3$ O atoms.

Part 2: Number of ethanol molecules produced

Step 1: Determine the balanced reaction

The reaction is: $3\ce{C2H4} + 3\ce{H2O}
ightarrow?\ce{C2H6O}$

• For C: 3 molecules of $\ce{C2H4}$ have $3 \times 2 = 6$ C atoms. Each $\ce{C2H6O}$ has 2 C atoms, so number of $\ce{C2H6O}$ molecules from C: $\frac{6}{2} = 3$.
• For H: 18 H atoms (from part 1), each $\ce{C2H6O}$ has 6 H atoms: $\frac{18}{6} = 3$.
• For O: 3 O atoms (from part 1), each $\ce{C2H6O}$ has 1 O atom: $\frac{3}{1} = 3$.

Final Answers

Table:

Chemical element	Number of atoms in the reaction
C	6
O	3

Number of ethanol molecules: 3