Simplify the following text for a Grade 8 native English-speaking person.
Original: Copper reacts with a combination of oxygen and hydrochloric acid to form a series of copper chlorides . Green-blue copper ( II ) chloride , when boiled with copper metal , undergoes comproportionation to form white copper ( I ) chloride .
Simplified: Some copper sulfide reacts with the copper ( I ) oxide to make copper and sulfur dioxide .