To determine which situations contain chemical changes, let's analyze each one:
I) Heating a pot of water leads to the formation of bubbles (steam) and condensation. This is a physical change as it involves changes in state (liquid to gas), not a change in the chemical composition of the water.
II) Mixing a translucent blue copper (II) sulfate solution with water resulting in a lighter blue color is a physical change. The composition of copper (II) sulfate remains unchanged; only the concentration of the solution changes.
III) When solid ammonium nitrate is added to water and the temperature drops significantly, this indicates an endothermic reaction. However, this is still a physical change because the ammonium nitrate dissolves in water without changing its chemical structure; its dissolution is a physical process.
IV) Mixing red and blue paint to create purple is also a physical change, as the pigments are simply mixed physically without any chemical reaction changing the compositions of the original paints.
Based on this analysis, none of the situations described represents a chemical change. Therefore, the correct response in this case would be "none of the above," as there are no options to indicate that. However, since this option is not present, the closest interpretation is:
D) I, II and III (since they all involve physical changes).
None of the options explicitly describes that there are only physical changes, but if strictly following your options, any situation involving physical changes does not contain chemical changes, leading us to choose none of the provided options as correct for containing chemical changes.
1 answer