Question

true or false when citric acid and baking soda mix ,carbon dioxide is produced and the temperature decreases. this must be a chemical change​

Answer 1

Answer:

When milk turns sour, this is a physical change because a change in odor does not indicate a chemical change. 20. When citric acid and baking soda mix, carbon dioxide is produced and the temperature decreases. This must be a chemical change

Answer 2

When citric acid and baking soda are mixed, carbon dioxide is produced and the temperature decreases. This must be a chemical change​. This statement is true.

Explanation:

• A chemical change can be identified by the change in state, change in colour, the evolution of gas and change in temperature.
• When citric acid and baking soda are mixed, sodium citrate, water and carbon dioxide gas are produced.
• The formation of carbon dioxide is identified by bubbles coming out of the water.
• The reaction is given as:

        $\[3NaHC{O_3} + {C_6}{H_8}{O_7} \to {C_6}{H_5}N{a_3}{O_7} + 3C{O_2} + 3{H_2}O\]$

• The reaction absorbs heat energy. Therefore, it is an endothermic reaction. Thus, the temperature decreases after the reaction.
• Therefore, it is a chemical change as both the evolution of gas and the change in temperature takes place.