Chemical reactions

Reactions are where chemistry actually happens, and this topic teaches you to name them, balance them and describe acids and bases correctly. You begin by identifying reaction types: synthesis, decomposition, single and double displacement, and combustion. The pattern of reactants and products usually gives the type away if you look for it. Next is balancing chemical equations. The rule students break most often is changing a subscript, which turns one substance into a different one, when only the coefficients in front may change. The last page covers acids, bases and the pH scale. Lower pH means more acidic, each step on the scale is a tenfold change, and neutral is seven, not zero. Throughout, count atoms on both sides as a final check; a balanced equation has exactly the same number of each atom on the left and the right. Go through the pages in order, try the practice questions, and only then compare with the answers on each page.