Chemistry Regent Exam August 2022
14. Which sample of matter can be separated into two different substances by physical means?
(1) liquid bromine (2) gaseous propane (3) solid sodium acetate (4) aqueous magnesium sulfate
Explanation: Physical means separate components of a mixture while chemical means can separate compounds. We must be looking for a mixture then since physical means were used. A mixture consists of two or more different substances. Let's look through the answer choices. Liquid bromine is one element and not a mixture. Gaseous propane is a compound that consists of carbon and hydrogen. Sodium acetate is a compound as well (metal + polyatomic ion). Aqueous magnesium sulfate is a mixture. Why? Aqueous means dissolved in water. Magnesium sulfate is a compound. Therefore, we have two substances: water and magnesium sulfate. Hint: If you ever see aqueous something, it will always be a mixture!
Answer: 4