what volume of oxygen gas is needed to completely combst 0.202L of butane (c4h10)gas?

Answer 1

Write a balanced equation. Here's the equation. Balance the equation yourself.

C4H10 + O2 -> CO2 + H2O

At STP, 1 mol = 22.4L. Use this to convert L to mol butane.

Use stoichiometry to solve this problem. Steps 1-3.
http://www.jiskha.com/science/chemistry/stoichiometry.html