CH4 + O2 ===> H2O + CO2 Bare Equation. This is a Combustion Reaction.
CH4 + 2O2====>2H2O + CO2 Balanced equation. You start with this.
Step One
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Find the moles of Methane.
1 mole of methane has a mass of
C = 12
O2 = 2 * 16 = 32
1 mol of CO2 = 12 + 32 = 44 grams / mole
Step Two
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Calculate the number of moles of methane.
given mass (g) = 25.5 grams
molar Mass = 44
mol = given mass / molar mass
mol = 25.5 / 44
mol = 0.5795 mols methane.
Step Three
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Find the moles of water.
For ever mole of methane, 2 moles of water are produced.
1 mol methane. . . . . . .. .0.5795 mols methane
=========== . . . . .= . .================ . . . . .
2 mol water . . . . . . . . . . .. .. . .x
Mole of water = 2 * 0.5795
mole of water = 1.159
Step Four
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Find the mass of water.
1 mol = 2H + O = 2 + 16 = 18 grams / mol
desired mass = mols * Molar mass
desired mass = 1.159 * 18
desired mass = 20.86 grams of water.
If you do these questions by dimensional analysis, this problem can be done all in 1 step. It would look like this.
25.5 g [1mol /44grams]*[2mol water / 1 mol meth]*[18 grams / 1 mol water]