Question

a) a chemical has changed size.
b) a chemical has changed to a different state (solid, liquid or gas)
c) a chemical has become a different shape.
d) a chemical has turned a different color.
when silver metal comes in contact with sulfur, silver sulfide forms and * 2 points the silver appears darker. this is a
a) change of form
b) chemical change
c) change of state
d) physical change

Explanation:

A chemical change results in the formation of a new substance. When silver reacts with sulfur to form silver - sulfide, a new compound is created. Changes in size, state, or shape are physical changes. Color change can be an indicator of a chemical change when a new substance is formed.

Answer:

1. None of the above options for the first part are chemical changes. They are physical changes (size, state, shape). The correct answer for what indicates a chemical change among common signs is not listed here.
2. B. chemical change (When silver metal reacts with sulfur to form silver - sulfide, a new chemical compound is formed, which is a chemical change)