A student takes four samples of a white crystalline solid and places each in a well plate. On top of each sample, she carefully places 20 drops of clear mystery liquids A, B, C and D. Her results for each well are:

Question

Liquid A: The solid dissolves quickly.
Liquid B: The solid appears unchanged.
Liquid C: A brownish colored liquid is produced.
Liquid D: Fizzing occurs and the well becomes warmer.

In which well does a PHYSICAL change occur?
Responses
A AA
B BB
C CC
D D

Answer 1

Based on the descriptions of the reactions in each well:

• Liquid A: The solid dissolves quickly. (This is a chemical change since the solid is undergoing dissolution and potentially altering its chemical properties).
• Liquid B: The solid appears unchanged. (This indicates a physical change because there is no alteration in the chemical structure of the solid; it remains the same).
• Liquid C: A brownish colored liquid is produced. (This suggests a chemical change due to the formation of a new substance).
• Liquid D: Fizzing occurs and the well becomes warmer. (This is also indicative of a chemical change, as gas is being produced and heat indicates a reaction).

Thus, a PHYSICAL change occurs in well B.