Aliquid fuel mixture contains 30.35% hexane (c6h14), 15.85% heptane (c7h16), and the rest octane (c8h18). what maximum mass of carbon dioxide is produced

To answer this item, the carbon dioxide produced can be determined by determining first the mass of carbon available for the reaction. Let our basis be 100g of fuel mixture.

carbon in hexane = (100 g)(0.3035)(6*12/6*12 + 14) = 25.41
carbon in heptane = (100 g)(0.1585)(7*12/7*12+16) = 13.31
carbon in octane = (100 g)(0.538)(8*12/8*12+18) = 45.3

The mass of carbon is 84.02. Each 12 g of carbon is present in 44 g of carbon dioxide. 

     (84.02 g carbon) x (44 g of carbon dioxide/ 12 g of carbon) 
   = 308.07 carbon dioxide/100 g of mixture

308.07 g carbon dioxide / 100 g of mixture

Cr(oh)3 -> cr(3+) + 3oh-