Final answer:
To burn 9340 L of acetylene gas completely, the molar ratio of acetylene to oxygen is 1:2.5. After calculation, we find 3.34 oxygen tanks are needed, so we round up to 4 tanks of oxygen.
Step-by-step explanation:
The question concerns the calculation of the number of oxygen tanks needed for the complete combustion of acetylene using an oxyacetylene welding torch. Given the chemical reaction 2 C₂H₂ +5 O₂ → 4 CO₂ + 2H₂O, we can determine the molar ratio of acetylene to oxygen, which is 1:2.5. Since one tank of acetylene contains 9340 L and one tank of oxygen contains 7000 L of O₂, we use the molar ratio to calculate the amount of oxygen needed to burn the acetylene completely.
To find the number of oxygen tanks required, we divide the acetylene volume by the molar ratio to get the volume of oxygen needed, and then we divide that by the volume one oxygen tank provides. 9340 L acetylene × (2.5 L oxygen / 1 L acetylene) = 23350 L oxygen needed. Then, 23350 L oxygen / 7000 L/tank yields approximately 3.34 tanks.
Since tanks cannot be fractionally used, we round up to ensure we have enough oxygen, resulting in 4 tanks of oxygen being required to burn the acetylene completely.