Question

butanol thermodynamics
combustion of butanol
butanol, c₄h₉oh, is used in varnishes and protective coatings for wood. the compound is flammable and must be properly stored.

what is the balanced net ionic equation for the combustion of butanol?

c₄h₉oh(l) + o₂(g) → co₂(g) + h₂o(g)

c₄h₉oh(l) + 8o₂(g) →4co₂(g) + 9h₂o(g)

c₄h₉oh(l) + 6o₂(g) →4co₂(g) + 4h₂o(g)

c₄h₉oh(l) + 6o₂(g) →4co₂(g) + 5h₂o(g)

Explanation:

To balance the combustion equation of butanol (\(C_4H_9OH\)), we balance the number of each atom (C, H, O) on both sides.

1. Carbon (C): There are 4 C atoms in \(C_4H_9OH\), so we need \(4CO_2\) (4 C on the product side).
2. Hydrogen (H): \(C_4H_9OH\) has \(10\) H atoms (\(9 + 1\) from \(-OH\)), so we need \(5H_2O\) (since \(5 \times 2 = 10\) H atoms).
3. Oxygen (O):

• Reactant side: \(O_2\) (let coefficient be \(x\)) and \(C_4H_9OH\) has 1 O atom.
• Product side: \(4CO_2\) has \(4 \times 2 = 8\) O atoms, and \(5H_2O\) has \(5 \times 1 = 5\) O atoms. Total O on product side: \(8 + 5 = 13\).
• O from \(C_4H_9OH\) is 1, so O from \(O_2\) is \(13 - 1 = 12\). Thus, \(x = \frac{12}{2} = 6\) (since each \(O_2\) provides 2 O atoms).

Putting it all together: \(C_4H_9OH(l) + 6O_2(g)
ightarrow 4CO_2(g) + 5H_2O(g)\).

Answer:

D. \(C_4H_9OH(l) + 6O_2(g)
ightarrow 4CO_2(g) + 5H_2O(g)\)