객관식
Which of the following represents the correct products of the reaction: FeCl_3 + 3NH_4OH → ?
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3. Chemical Reactions
Balancing Chemical Equations
객관식
Which of the following is the correctly balanced chemical equation for the combustion of propane (C_3H_8)?
A
C_3H_8 + 5 O_2 → 3 CO_2 + 4 H_2O
B
C_3H_8 + 3 O_2 → 3 CO_2 + 4 H_2O
C
C_3H_8 + 4 O_2 → 3 CO_2 + 4 H_2O
D
C_3H_8 + 5 O_2 → 2 CO_2 + 4 H_2O
검증된 단계별 안내1
Write the unbalanced chemical equation for the combustion of propane: \(\mathrm{C_3H_8 + O_2 \rightarrow CO_2 + H_2O}\).
Balance the carbon atoms first. Since propane has 3 carbon atoms, place a coefficient of 3 in front of \(\mathrm{CO_2}\): \(\mathrm{C_3H_8 + O_2 \rightarrow 3 CO_2 + H_2O}\).
Balance the hydrogen atoms next. Propane has 8 hydrogen atoms, so place a coefficient of 4 in front of \(\mathrm{H_2O}\) because each water molecule has 2 hydrogens: \(\mathrm{C_3H_8 + O_2 \rightarrow 3 CO_2 + 4 H_2O}\).
Balance the oxygen atoms last. On the right side, there are \(3 \times 2 = 6\) oxygen atoms from \(\mathrm{CO_2}\) and \(4 \times 1 = 4\) oxygen atoms from \(\mathrm{H_2O}\), totaling 10 oxygen atoms. Since oxygen gas is \(\mathrm{O_2}\), divide 10 by 2 to get 5 molecules of \(\mathrm{O_2}\): \(\mathrm{C_3H_8 + 5 O_2 \rightarrow 3 CO_2 + 4 H_2O}\).
Verify that all atoms are balanced on both sides: 3 carbons, 8 hydrogens, and 10 oxygens. This confirms the balanced equation.
