Question

How many grams of o2(g) are needed to completely burn 70.2 g of C3H8(g)

Answer 1

First you must write a balanced chemical equation.

C3H8 + 5O2 --> 3CO2 + 4H2O

From there, we can set up the stoichiometry equation to solve.

g O2= 70.2 g C3H8 X (1 mol C3H8/44.0962g C3H8) X (5 mol O2/1 mol C3H8) X (31.998g O2/1 mol O2)

Now solve, and you should get 254.7 g O2. Hope this helped!