Given a scientific passage and an answer, generate a question for the given answer.

[EX Q]: Passage: In this equation, the letters A and B represent the reactants that begin the reaction, and the letter C represents the product that is synthesized in the reaction. The arrow shows the direction in which the reaction occurs. Answer: reaction mechanism
[EX A]: What term is used to describe the sequence of elementary steps that together comprise an entire chemical reaction?

[EX Q]: Passage: Physical properties include color, density, hardness, and melting and boiling points. Answer: physical
[EX A]: Hardness, density, color, and melting and boiling points are all considered what types of properties?

[EX Q]: Passage: Salts of weak acids or bases can affect the acidity or basicity of their aqueous solutions. Answer: basicity
[EX A]:
Salts of weak acids or bases can affect the acidity or what of their aqueous solution?