Question

Marco wants to investigate the chemical properties of sodium bicarbonate, or baking soda. He plans to carry out the tests below.

Test 1: Mix a teaspoon of sodium bicarbonate into a cup of warm water to see if it dissolves.

Test 2: Mix a teaspoon of sodium bicarbonate into a cup of vinegar to see if it fizzes.

Test 3: Heat a teaspoon of sodium bicarbonate in the oven to see if its melting point is less than 400 degrees Fahrenheit.

Which statement provides the best assessment of his tests?

Only Test 3 will indicate a chemical property of sodium bicarbonate. Tests 1 and 2 will show a physical property of the substance.
Only tests 1 and 2 will indicate chemical properties of sodium bicarbonate. Test 3 will show a physical property of the substance.
Only Test 2 will indicate a chemical property of sodium bicarbonate. Tests 1 and 3 will show a physical property of the substance.
Only tests 1 and 3 will indicate chemical properties of sodium bicarbonate. Test 2 will show a physical property of the substance.
A B C OR D

Answer 1

C

Test 1: dissolving = physical property (solubility).
Test 2: fizzing with vinegar = chemical property (reacts with acid, producing CO2).
Test 3: measuring melting point = physical property.

(Practical note: sodium bicarbonate actually decomposes on strong heating rather than truly melting, so very high heating can show a chemical change — but the test as stated is a melting-point/physical-property test.)