Answer:
17.5 moles of oxygen gas
Explanation:
Propane burns with the help of oxygen according to the following reaction
[tex]C_3H_8+5O_2=3CO_2+4H_2O[/tex]
It can be seen that for 1 mole of propane 5 moles of oxygen is required.
[tex]1\ \text{mol of }C_3H_8=5\ \text{mol of }O_2[/tex]
[tex]3.5\ \text{mol of }C_3H_8=3.5\times 5=17.5\ \text{mol of }O_2[/tex]
The reaction will be
[tex]3.5C_3H_8+17.5O_2=10.5CO_2+14H_2O[/tex]
Therefore 17.5 moles of oxygen gas will be needed to burn 3.5 moles of propane.
