Question

students are each given a 20 - gram sample of an unknown solid compound in a clear plastic bag. they are instructed to break the material into smaller parts by gently hitting it with a hammer. some of the parts break into large chunks and some look like a fine powder. which statement correctly describes these broken pieces of the sample? each piece contains the same number of atoms. the fine powder pieces are individual atoms broken from the solid. each piece contains the same proportion of different elements. the larger pieces are still compounds and the smaller pieces are elements.

Explanation:

A compound has a fixed proportion of elements by mass. Breaking a compound physically (like hitting with a hammer) does not change its chemical composition. So, each piece (whether large chunk or fine powder) still has the same proportion of different elements as the original compound.

• The first option: Different - sized pieces (different masses) will have different numbers of atoms (since mass is related to the number of atoms via molar mass).
• The second option: Breaking a compound with a hammer doesn't break it into individual atoms (that would require a chemical reaction).
• The fourth option: Breaking a compound physically doesn't turn parts of it into elements (a compound is made of elements chemically combined, and physical force isn't enough to separate them into elements).

Answer:

Each piece contains the same proportion of different elements.