Question

in the decomposition of water, why is twice as much hydrogen as oxygen formed? (1 point)
hydrogen gas has two atoms, and oxygen gas has one atom.
there are two atoms of hydrogen and one atom of oxygen in a water molecule.
some oxygen gas escapes the reaction, and hydrogen gas is conserved.
hydrogen atoms are twice the size of oxygen atoms.

Explanation:

Step1: Analyze the chemical formula of water

The chemical formula of water is \(H_2O\). This means there are two hydrogen atoms (\(H\)) and one oxygen atom (\(O\)) in a water molecule.

Step2: Consider the decomposition reaction

When water (\(H_2O\)) decomposes (e.g., through electrolysis \(2H_2O
ightarrow2H_2 + O_2\)), for every water molecule decomposed, 2 hydrogen atoms combine to form a hydrogen gas (\(H_2\)) molecule and 2 oxygen atoms combine to form an oxygen gas (\(O_2\)) molecule. From the formula \(H_2O\), the ratio of hydrogen to oxygen atoms in water is \(2:1\). So when decomposed, the number of hydrogen gas molecules (\(H_2\)) produced will be twice the number of oxygen gas molecules (\(O_2\)) produced (because for \(n\) water molecules, there are \(2n\) \(H\) atoms forming \(n\) \(H_2\) molecules and \(n\) \(O\) atoms forming \(\frac{n}{2}\) \(O_2\) molecules, and the ratio of \(H_2\) to \(O_2\) is \(2:1\) in terms of molecule - number, which also means twice as much hydrogen gas in terms of volume under the same temperature and pressure conditions as per Avogadro's law (equal volumes of gases at the same temperature and pressure contain equal number of molecules)).

Answer:

There are two atoms of hydrogen and one atom of oxygen in a water molecule.