Final answer:
Fuel gases for oxy-fuel torches include acetylene, propane, methane, and butane, which when combined with oxygen, create high-temperature flames used for cutting and welding. Each fuel burns with oxygen in specific ratios to produce carbon dioxide and water.
Step-by-step explanation:
Fuel gases used in oxy-fuel torches are important for various applications such as welding, cutting, and heating. Gases like acetylene and oxygen form a combustive mixture that is commonly used due to the high temperatures achieved when acetylene burns in the presence of oxygen. Acetylene's formula is C₂H₂, and when it burns with oxygen, the reaction is 2 C₂H₂ (g) + 5 O₂ (g) → 4 CO₂ (g) + 2 H₂O(l). This reaction shows that 2.5 molecules of oxygen are needed for every molecule of acetylene.
Propane (C₃H₈) is another common fuel used with oxygen, as it burns to produce carbon dioxide and water. The balanced equation for the combustion of propane is C₃H₈ (l) + 5O₂(g) → 3CO₂(g) + 4H₂O(l). Similarly, other hydrocarbons like methane (CH₄) and butane (C₄H₁₀) are also used in such torches alongside oxygen, reacting to form CO₂ and H₂O when complete combustion occurs. Butane, often found in lighters, has the balanced equation 2 C₄H₁₀(g) + 13 O₂(g) → 8 CO₂(g) + 10 H₂O(l).
An example exercise given is calculating the number of oxygen tanks needed for a given volume of acetylene for an oxyacetylene torch. When acetylene and oxygen are reacted, they do so at a volume ratio of 2.5:1, and thus, you can calculate the number of tanks needed based on the volumes provided at standard conditions.