- Chemical reactions preserve the identity of nuclei; therefore, nuclear changes such as gaining or losing protons do not occur.
- The fundamental change in this reaction is the breaking of existing bonds in \(H_2\) and \(O_2\) and the formation of new covalent bonds in \(H_2O\).
- Valence electrons of hydrogen atoms are shared with oxygen atoms, confirming the formation of covalent bonds.
- The correct statements are:
- The bond in \(H_2\) is broken, and new bonds are formed between hydrogen and oxygen atoms.
- Each electron associated with a hydrogen atom is shared with an oxygen atom.
Explanation
- Analysis of the Chemical Reaction Process
The chemical equation \(2H_2 + O_2 \rightarrow 2H_2O\) describes a chemical reaction. In a chemical reaction, the identities of elements are conserved because the atomic nuclei remain unchanged. Changes in a reaction are limited to the rearrangement of atoms and the breaking and forming of chemical bonds, which involves the movement or sharing of valence electrons. We will analyze each statement based on these principles.
- Evaluation of Proton Changes in the Hydrogen Nucleus
The statement "The hydrogen nucleus loses protons" is incorrect. Losing or gaining protons changes the identity of an element (for example, hydrogen becoming helium). Such processes occur in nuclear reactions, not in ordinary chemical reactions like combustion. Therefore, the hydrogen nucleus remains constant.
- Evaluation of Proton Changes in the Oxygen Nucleus
The statement "The oxygen nucleus gains protons" is also incorrect. Just like with hydrogen, nuclear composition remains unchanged in chemical reactions. Oxygen nuclei do not gain protons to form new elements during the reaction of hydrogen and oxygen to form water.
- Evaluation of Bond Rearrangement
The statement "The bond in \(H_2\) is broken, and new bonds are formed between hydrogen and oxygen atoms" is correct. This is the fundamental definition of a chemical reaction: the bonds holding the reactants together (in this case, the \(H-H\) bonds in \(H_2\) and the \(O=O\) bond in \(O_2\)) are broken, and the atoms are rearranged to form new chemical bonds (the \(O-H\) bonds in \(H_2O\)).
- Evaluation of Electron Sharing
The statement "Each electron associated with a hydrogen atom is shared with an oxygen atom" is correct. Water is a covalent compound where electrons are shared between the oxygen and hydrogen atoms to achieve a stable electron configuration. In this reaction, the valence electrons of hydrogen are indeed shared with the oxygen atoms.
- Summary of Findings
Based on our analysis, the correct statements are:
- The bond in \(H_2\) is broken, and new bonds are formed between hydrogen and oxygen atoms.
- Each electron associated with a hydrogen atom is shared with an oxygen atom.
These two statements accurately describe the chemical changes occurring during the formation of water.
Examples
Understanding how chemical bonds form is crucial for fields like pharmacology and material science. For example, when creating a new medicine, chemists must understand how atoms bond together to ensure the drug works correctly in the human body. Just as hydrogen and oxygen bond to form water, molecules in medicine bond to interact with cells, demonstrating that the principles of electron sharing are foundational to modern science and everyday life.