Hydrogen is a possible future fuel. However, elemental hydrogen is rare, so it must be obtained from a hydrogen-containing compound such as water. If hydrogen were obtained from water, how much hydrogen, in grams, could be obtained from 1.0 L of water? (density of water = 1.0 g>cm3 )

The process of extracting hydrogen from water is an essential science today given our quest for clean, sustainable energy sources. Hydrogen, often referred to as a clean fuel, can be produced through various methods, one of the simplest being electrolysis of water. This method involves passing an electric current through water to separate the hydrogen and oxygen atoms.

Due to its composition, one molecule of water (H2O) contains two hydrogen atoms bonded to one oxygen atom. When electric current is applied, water molecules are split to form hydrogen gas (H2) and oxygen gas (O2). This process not only promises a supply of hydrogen but does so without direct emission of pollutants or greenhouse gases if the electricity used is from a renewable source.

Stoichiometry is a branch of chemistry that deals with the quantitative relationships of the substances consumed and produced in chemical reactions. In the context of our hydrogen extraction problem, stoichiometry allows us to calculate the exact amount of hydrogen that can be produced from a known quantity of water.

Understanding the stoichiometry of water, we know that it is comprised of two parts hydrogen to one part oxygen. By using the coefficients of a balanced chemical reaction, which in the case of water's decomposition is 2H2O → 2H2 + O2, it becomes clear that from two molecules of water, we can obtain two molecules of hydrogen and one molecule of oxygen. This fixed ratio is crucial for predicting the amount of hydrogen gas that will be produced from a given amount of water.

The molar mass of a substance is the mass in grams of one mole of that substance. It's a fundamental concept for chemists because it serves as a bridge between the atomic world and the macroscopic world we live in. To calculate the molar mass, we use the atomic masses of the elements comprising the substance, as listed in the periodic table, and add them according to their ratio in a molecule.

In the original problem, the molar mass of hydrogen is around 1.008 g/mol, and oxygen is approximately 16.00 g/mol. Therefore, for water, which has two hydrogen atoms and one oxygen atom (H2O), the molar mass is the sum of twice the atomic mass of hydrogen and the atomic mass of oxygen. This calculation is critical when determining the mass of hydrogen that can be acquired from a specific amount of water, as we need to know the proportion of hydrogen within water's total mass.