Question

hydrogen and oxygen are gases, but when they react to form water, the product is a liquid. what is the best explanation for this change in properties?
because water is a liquid, and liquids always have different properties.
because the arrangement of hydrogen and oxygen atoms is different in water.
because the original atoms are destroyed to make the new substance.
because forming a new substance requires creating new atoms.

Explanation:

When hydrogen and oxygen react to form water, a chemical reaction occurs. In a chemical reaction, atoms are rearranged to form new substances with different properties. The properties of a substance depend on the arrangement of its atoms. Water has different properties than hydrogen and oxygen because the atoms are arranged differently in water. Atoms are not destroyed or created in a chemical reaction (so options 3 and 4 are wrong). Option 1 is a circular argument and not a proper scientific explanation.

Answer:

Because the arrangement of hydrogen and oxygen atoms is different in water.