Question

Using the following equation, `2C_2H_6 + 7O_2 -> 4CO_2 + 6H_2O`, if 2.5 g `C_2H_6` react with 170 g `O_2`, what is the limiting reactant?

Answer 1

Clearly, ethane is the limiting reagent. Why `"clearly"`?

Explanation:

You have the stoichiometric equation, which tells you, unequivocally, that 2 equiv ethane reacts with 7 equiv dioxygen gas (alternatively 1 equiv ethane reacts with 3.5 equiv `O_2`).

`"Moles of ethane"=(2.5*g)/(30.1*g*mol^-1)=0.083*mol`.

`"Moles of dioxygen"=(170*g)/(32.0*g*mol^-1)=5.3*mol`.

There is a stoichiometric EXCESS of dioxygen gas.

Can you tell us how much carbon dioxide would be produced given complete combustion?