What are the basics of physics. i want to learn them for an exam?

What is the type of the reaction below? bacl2 + h2so4 → 2 hci + baso4 double replacement synthesis single replacement decomposition

Give one example to show that when substances are mixed,it may result in a chemical or a physical change depending on the conditions.

Use 4 to 5 complete sentences, explain the concepts of beats and how beats are produces.