Question

What do these two changes have in common? Select all that apply. rust forming on a metal gate snails growing shells (1 point) Responses Both are only physical changes Both are only physical changes Both are chemical changes Both are chemical changes Both conserve mass Both conserve mass Both are changes in state

Answer 1

The two changes, rust forming on a metal gate and snails growing shells, can be considered in the following ways:

1. Both are chemical changes: Rusting is a chemical reaction where iron reacts with oxygen in the presence of moisture to form iron oxide (rust). The growth of shells in snails involves biochemical processes where the snail secretes calcium carbonate to form its shell, which is also a chemical change.

2. Both conserve mass: According to the law of conservation of mass, in any chemical reaction, mass is conserved. The mass of the initial reactants (like iron and oxygen) will equal the mass of the products (rust). Similarly, the process of shell formation in snails also involves mass conservation as the calcium and other materials combine to form the shell.

So, the applicable selections are:

• Both are chemical changes
• Both conserve mass