Question

Justin mixed two clear liquids together during an experiment and made the following observations:

Answer 1

Answer: Option (B) is the correct answer.

Explanation:

A chemical reaction in which energy is absorbed by the reactant molecules is known as endothermic reaction. In this type of reaction there occurs decrease in temperature.

For example, Justin mixed two clear liquids together during an experiment and he noticed that decrease in temperature occurs without any refrigeration or other action to change the temperature.

Then it means an endothermic reaction has occurred.

Sometimes, chemical changes also leads to change in color of the reaction mixture.

Whereas a chemical reaction in which energy is released by the reactant molecules is known as exothermic reaction. In this type of reaction there occurs an increase in temperature.

A physical change is that change which does not lead to any difference in chemical properties of a substance.

For example, mass, density, etc are all physical properties.

On the other hand, a chemical reaction is that change which leads to change in chemical properties of a substance.

For example, combustion, toxicity, etc are all chemical properties.

Thus, we can conclude that the statement a chemical change occurred, and this caused the liquid’s physical properties to change, best describes Justin’s experiment.

Answer 2

Answer:

B. A chemical change occurred which caused the liquid's physical properties to change.

Explanation:

The reduction of the temperature of the system meant that the reaction absorbed heat energy from it. This shows that a chemical reaction was in progress. New products were formed, and this is proved by the change in the color to blue.