Question

what do these two changes have in common?
adding dish soap to water in a sink
a log decomposing in the woods
select all that apply.
both are caused by heating. both conserve mass.
both are chemical changes. both are only physical changes

Explanation:

• Law of Conservation of Mass: This law states that mass is neither created nor destroyed in a chemical reaction or physical change. For "adding dish soap to water in a sink" (a physical change), the mass of the soap - water mixture is the sum of the mass of the soap and the mass of the water. For "a log decomposing in the woods" (a chemical change, as new substances are formed during decomposition), the mass of the reactants (the log and the substances it reacts with, like oxygen) is equal to the mass of the products (e.g., carbon dioxide, water, and other decomposed materials).
• Rejecting other options:
• "Both are caused by heating": Adding dish soap to water is not caused by heating. Decomposing of a log can occur at normal temperatures (not necessarily due to heating).
• "Both are chemical changes": Adding dish soap to water is a physical change (no new chemical substances are formed, just a mixture).
• "Both are only physical changes": A log decomposing is a chemical change (new substances are formed as a result of biological and chemical processes in decomposition).

Answer:

Both conserve mass.