In the decomposition of water, why is twice as much hydrogen as oxygen formed?
1. Some oxygen gas escapes the reaction, and hydrogen gas is conserved.
2. Hydrogen gas has two atoms, and oxygen gas has one atom.
3. There are two atoms of hydrogen and one atom of oxygen in a water molecule.
4. Hydrogen atoms are twice the size of oxygen atoms.
The correct explanation is option 3: There are two atoms of hydrogen and one atom of oxygen in a water molecule.
The correct answer is 3. There are two atoms of hydrogen and one atom of oxygen in a water molecule. In the decomposition of water, the water molecule (H2O) breaks down to form two molecules of hydrogen gas (H2) and one molecule of oxygen gas (O2). This is because each water molecule consists of two hydrogen atoms bonded to one oxygen atom.
The correct answer is 3. There are two atoms of hydrogen and one atom of oxygen in a water molecule.
To understand why twice as much hydrogen is formed, we need to look at the chemical formula for water, which is H2O. This formula tells us that each water molecule contains two hydrogen (H) atoms and one oxygen (O) atom.
During the decomposition of water, the water molecule is broken down into its constituent elements, hydrogen and oxygen. Since each water molecule has two hydrogen atoms, it means that twice as much hydrogen is formed compared to oxygen.
Options 1, 2, and 4 are not correct explanations:
- Option 1 states that some oxygen gas escapes the reaction and hydrogen gas is conserved. This is incorrect because the amount of oxygen formed is not affected by the escape of oxygen gas. The amount of oxygen will always be half of the amount of hydrogen formed.
- Option 2 mentions that hydrogen gas has two atoms, and oxygen gas has one atom. While this is true, it does not explain why twice as much hydrogen is formed. The explanation lies in the composition of a water molecule, as mentioned above.
- Option 4 states that hydrogen atoms are twice the size of oxygen atoms. While this statement is true, the size of atoms does not determine the amount of a substance formed during a chemical reaction. It is the composition and stoichiometry of the substances involved that determine the amounts. In the case of water decomposition, the ratio of hydrogen and oxygen atoms in a water molecule determines the ratio in which they are formed.