Question

you already know that matter can be a pure substance or a mixture. and you know that both creating and separating mixtures are examples of physical changes. lets talk about the pure substances. pure substances include elements, like sodium (na) and chlorine (cl), and compounds, which are two or more elements chemically bonded. salt, which contains one atom of sodium and one atom of chlorine, is a compound (nacl). for compounds to separate into elements, chemical bonds must break. similarly, for atoms of two elements to become compounds, chemical bonds must form. in both cases, chemical changes occur. based on this passage, salt choose one option a can be separated into sodium and chloride in a physical change. b is an element. c is a pure substance. d can be created when a chemical bond breaks.

Explanation:

• The passage states that pure substances include elements and compounds. Salt (NaCl) is a compound, so it is a pure substance.
• Option A: Separating salt into sodium and chlorine requires breaking chemical bonds (a chemical change, not physical).
• Option B: Salt is a compound, not an element.
• Option D: Salt is created when chemical bonds form (sodium and chlorine bonding), not when they break.

Answer:

C. is a pure substance.