chemistry
posted by tracey .
how many moles of butane gas c4h10 react to produce 3.50moles of water?

I believe you would get the molar mass of C4H10 and also the molar mass of water (H20). So C4H10 gives us a molar mass of 58.14 grams/mol and water gives us a molar mass of 18.02 grams/mol. You then would set it up 58.14 grams x mol/ 18.02 grams. Grams cancel and leave you with moles.
58.14g x mol = ?
18.02 g 
oops, disregard the last part it didn't line up right. It will just be 58.14/ 18.02 which gives you moles

2C4H10 + 13O2 ==> 8CO2 + 10H2O
Use the coefficients in the balanced equation to convert from moles of one thing to moles of any other in the same equation.
moles butane = 3.5 moles H2O x (2 moles butane/10 moles H2O) = 3.5*(2/10) = ??