that water can be made from hydrogen and oxygen molecules. In addition,
it says that two moles of hydrogen and one mole of oxygen are required
to produce two moles of water. As an expression of the conservation
of atoms, it indicates that for every four atoms of hydrogen and
two atoms of oxygen (in
molecules), only two molecules of water can be obtained, which contain
the same total of four H and two O atoms.
From the balanced equation, one can obtain information about the
relative amounts of reactants and products involved. The molecular
weights of ,
are 2.02 g, 32.00 g, and 18.02 g, respectively. Hence 2 x 2.02 g
of hydrogen react with 1 x 32.00 g of oxygen to form 2 x 18.02 g
2(2.02) g + 32.00 g = 2(18.02) g
g = 36.04 g
The total weight of reactants before the reaction is the same as
the weight of the products after the reaction; mass has been conserved.
is a low-pollution fuel gas that can be burned in existing automobile
engines with only minor engine adjustments. How many moles of
are required to burn one mole of propane, and how many grams of
are used with a kilogram of propane?