Balancing Equations

10SCIE - Fire & Fuels

Finn Le Sueur

2024

Ngā Whāinga Ako

  1. Write the word equation for complete combustion
  2. Write the balanced symbol equation for complete combustion

Mahi Tuatahi

  1. What are some key observations that would indicate incomplete combustion?
  2. What are some key observations that would indicate complete combustion?

Keywords

  • Reactants: Butane, oxygen, hydrogen, vinegar etc.
  • Products: Carbon dioxide, water, carbon etc.
  • Chemical Compound: \(H_{2}O\), \(CO_{2}\), \(NH_{3}\), \(NaCl\) etc.
  • Atom/Molecule: H, C, O, Au, Ca

Question

What happens to the atoms/molecules during a chemical reaction?

  • No new atoms are created or destroyed
  • Mass of the reactants = mass of the products
  • The reactants change molecular structure
  • Two or more new products are made
  • The atoms are rearranged
  • Energy can be produced if bonds are broken (combustion)

Complete Combustion of Methane

Complete the word and balanced symbol equation for this reaction.

\[\begin{aligned} methane \quad + \quad oxygen &\rightarrow \hspace{2cm} + \hspace{2cm} \newline CH_{4} \quad + \quad O_{2} &\rightarrow \hspace{2cm} + \hspace{2cm} \newline \end{aligned}\]

Answer

Complete combustion of methane:

\[\begin{aligned} methane \quad + \quad oxygen &\rightarrow \quad \text{carbon dioxide} + \quad water \newline CH_{4} \quad + \quad O_{2} &\rightarrow \quad CO_{2} + \quad H_{2}O \newline CH_{4} \quad + \quad 2O_{2} &\rightarrow \quad CO_{2} + \quad 2H_{2}O \text{ (balanced)} \end{aligned}\]

Balance these reactions:

\[\begin{aligned} & C \quad + \quad O_{2} \rightarrow \quad CO_{2} \newline & H_{2} \quad + \quad O_{2} \rightarrow \quad H_{2}O \newline & N_{2} \quad + \quad H_{2} \rightarrow \quad NH_{3} \newline & CH_{4} \quad + \quad O_{2} \rightarrow \quad CO_{2} + \quad H_{2}O \end{aligned}\]

Answer

\[\begin{aligned} & C \quad + \quad O_{2} \rightarrow \quad CO_{2} \newline & 2H_{2} \quad + \quad O_{2} \rightarrow \quad 2H_{2}O \newline & N_{2} \quad + \quad 3H_{2} \rightarrow \quad 2NH_{3} \newline & CH_{4} \quad + \quad 2O_{2} \rightarrow \quad CO_{2} + \quad 2H_{2}O \end{aligned}\]

Extra Work

  1. Page 9: Fuels & Combustion
  2. Balancing Equations Worksheet