What is always true according to the Law of Conservation of Matter
1. The total number of molecules before and after a chemical reaction stays the same.
2. Atoms created during a chemical reaction must have the same mass as the atoms in reactants.
3. New molecules cannot be formed from the reactants during a chemical reaction.
4. Atoms can be rearranged during a chemical reaction but cannot be added or taken away.
4. Atoms can be rearranged during a chemical reaction but cannot be added or taken away.
The option that is always true according to the Law of Conservation of Matter is:
4. Atoms can be rearranged during a chemical reaction but cannot be added or taken away.
The correct answer is option 4: Atoms can be rearranged during a chemical reaction but cannot be added or taken away.
The Law of Conservation of Matter states that during a chemical reaction, matter is neither created nor destroyed; it is only transformed or rearranged. This means that the total number of atoms of each element remains constant before and after a chemical reaction.
To understand why option 4 is correct, we need to consider the atomic composition of substances involved in a reaction. Atoms are the smallest units of matter and cannot be divided or destroyed. In a chemical reaction, atoms can be rearranged to form new molecules, but the total number of atoms of each element must remain the same.
While the other options in the question might seem plausible, they are not always true according to the Law of Conservation of Matter. For example, option 1 is incorrect because the total number of molecules may change if a reaction involves the creation or destruction of molecules. Option 2 is also incorrect because while the mass of atoms remains constant, new atoms with different masses can be formed during a reaction (e.g., through nuclear reactions). Option 3 is incorrect because new molecules can indeed be formed from reactants during a reaction, as long as the total number of atoms of each element is conserved.
Therefore, option 4 best reflects the true nature of the Law of Conservation of Matter.