What quantities of reagents are used to obtain 18 g of water from simple substances?

The reaction of obtaining water from simple substances: 2H2 + O2 = 2H2O.
1 * 2 + 16 = 18 is the molar mass of water.
18/18 = 1 mol – the amount of water substance.
For two moles of water, there are two moles of hydrogen. This means that the amount of hydrogen is equal to the amount of water and is equal to 1 mol – answer1.
There is one mole of oxygen for two moles of water. This means that the amount of oxygen substance is: 2 * 1 = 2 mol

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