C2H6O + 3O2 → 3H2O + 2CO2

Question

How many grams of ethanol (C2H6O) are needed to synthesize 8.00 g H2O vapor?

Answer 1

C2H6O + 3O2 → 3H2O + 2CO2

How many grams of ethanol (C2H6O) are needed to synthesize 8.00 g H2O vapor?

First check to see if your equation is balanced. Compare the number of molecules of each element in the reactants to products.

Reactants: Products:

C = 2 C = 2

H = 6 H = 6

O = 7 O = 7

Since the numbers match the equation is balanced.

Next figure out the molar mass of C₂H₆O and H₂O. Start by finding the atomic weight of each element on the periodic table.

C = 12.011 g/mol

H = 1.008 g/mol

O = 15.999 g/mol

Multiply these values by the number of atoms in each substance to get the molar mass.

2(12.011) + 6(1.008) + 15.999 = 24.022 + 6.048 + 15.999 = 46.069 g/mol C₂H₆O

2(1.008) + 15.999 = 2.016 + 15.999 = 18.015 g/mol H₂O

Next find the number of moles in the product of 8.0 g H₂O using the molar mass.

8.0 g H₂O x 1 mol H₂O = 0.444 mol H₂O

18.015 g H₂O

For every one mole of C₂H₆O in the equation there are 3 moles of H₂O. Use this ratio to find the moles of C₂H₆O.

0.444 mol H₂O x 1 mole C₂H₆O = 0.148 moles C₂H₆O

3 moles H₂O

Now use the known moles of C₂H₆O and the molar mass to find the amount in grams.

0.148 mol C₂H₆O x 46.069 g C₂H₆O = 6.818 g C₂H₆O

1 mol C₂H₆O