When gas contains 10 percent ethanol how much ethanol is in a gallon of gas?
For every gallon of gas containing 10% ethanol (referred to as
E10 gas), it will contain 1/10th gallon of ethanol (about 12 ounces
by volume). Ethanol is primarily used to oxygenate the gas and
replace the chemical MBTE, which pollutes groundwater. HOWEVER,
since most ethanol in the US comes from corn, it is important to
note that using ethanol in gasoline causes GREATER pollution than
just gasoline alone. This is because it actually takes more energy
to produce corn based ethanol than is extracted from it. Until
better technologies for ethanol production are available (e.g.
algae), it is best for the environment to avoid gas containing
ethanol if possible (some states mandate it).