Why is Diet Coke and mentos a chemical change?

Mixing Diet Coke and Mentos results in a physical change, not a chemical change. Here's why:

Physical change: A physical change alters the physical properties or form of a substance, but its chemical composition remains the same. In the case of Diet Coke and Mentos, the reaction creates bubbles that physically change the appearance of the liquid. The gas present in the soda rapidly escapes, causing the drink to shoot up and froth out of the container.

No chemical reaction: When Diet Coke and Mentos come into contact, there is no chemical reaction between their components. The chemical composition of both substances remains unchanged. The interaction between the rough Mentos surface and the dissolved carbon dioxide (CO2) in the soda leads to nucleation, which encourages the rapid release of CO2 gas.

Temporary effect: The frothing effect observed in the mixture of Diet Coke and Mentos is a temporary physical change. Once the escaping CO2 gas dissipates, the soda will return to its original state, with its chemical composition unaffected.

Examples of chemical change: In contrast, chemical changes produce new substances with different chemical properties and molecular structures. Examples include burning paper (combustion), rusting of iron (oxidation), and baking a cake (chemical reactions among ingredients resulting in a different substance).

In summary, mixing Diet Coke and Mentos results in a physical change characterized by the formation and release of CO2 gas, leading to fizzing and frothing without altering the chemical composition of the substances involved.