If 12.7 grams of hydrogen reacted with an unknown amount of oxygen, how many grams of water would be produced? (Write a balanced equation and show your work under the equation)

48 g.

Explanation:

    2H2    +   1 O2   >    2H2O

m = 12.7g                              m = ?

Get the number of moles for Hydrogen gas (H2) by dividing the mass by the molar mass (1.01g/mol as listed in the periodic table for its atomic mass)

12.7/1.01 = 12.57 mol of H2

Now use the mole to mole ratio of Hydrogen gas (H2) and water (H2O).

From the balanced equation, we can see that 2 mol of H2 gives us 2 mol of H2O. Since both of the ratios are equal (2:2), the moles we have for hydrogen gas is the same as the moles we get for water.

12.57 mol of H2O

Now that we have the amount of mol for H2O produced in this reaction, we can convert it to grams by multiplying the moles by the molar mass.

Molar mass of H2O = (1.01 x 2) + (16) = 18.02g/mol

12.57 x 18.02 = 226.5g (rounded)

Therefore 226.5g of water will be produced in this reaction