Question

what do these two changes have in common? melting wax mixing chocolate syrup into milk select all that apply. both are chemical changes. both are changes of state. both conserve mass. both are only physical changes.

Explanation:

• Chemical changes: A chemical change results in the formation of new substances. Melting wax and mixing chocolate syrup into milk do not form new substances. So the statement "Both are chemical changes" is incorrect.
• Changes of state: Melting wax is a change of state (solid to liquid). But mixing chocolate syrup into milk is a physical mixing (forming a homogeneous mixture) and not a change of state. So the statement "Both are changes of state" is incorrect.
• Conserve mass: According to the law of conservation of mass, mass is conserved in all physical and chemical changes. Melting wax (physical change) and mixing chocolate syrup into milk (physical change) both conserve mass.
• Only physical changes: A physical change does not change the chemical composition of a substance. Melting wax (only changes the state from solid to liquid, chemical composition of wax remains the same) and mixing chocolate syrup into milk (just forms a mixture, no new chemical substances are formed) are physical changes.

Answer:

C. Both conserve mass, D. Both are only physical changes.