Hello!
First, find the molar mass of hydrogen and oxygen. We'll use this to find out how many moles there are in 4.8 and 38.4 grams of hydrogen and oxygen (respectively). Note that a mole is 6.02x10²³ atoms/molecules.
Molar mass of hydrogen: 1.007 g/mol
Molar mass of oxygen: 15.999 g/mol
Now, find out how many moles are in the given quantities.
Hydrogen: 4.8 / 1.007 = 4.767 (about) moles
Oxygen: 38.4 / 15.999 = 2.4 (about) moles
Now, water is made of two hydrogen atoms and one oxygen. Since there is more oxygen than two hydrogens, divide 4.767 by 2 to see how many molecules can be made.
4.767/2 = 2.3835
Therefore, about 2.3835 moles of water would form.
To find the molar mass of this, find the molar mass of water. To do this, add together the molar mass of two hydrogens and one oxygen.
2 * 1.007 + 15.999 = 18.013
Now, multiply 18.013 by 2.3835.
18.013 * 2.3835 = 42.934 grams
Therefore, about 2.3835 moles or 42.934 grams of water would form.
Hope this helps!
