1What conclusion can be drawn about the rate of the chemical reaction between baking soda and lemon juice?
2Two test tubes each contain 5 ml of hydrogen peroxide, and 2 g of manganese dioxide is added to one of them. In which test tube does the chemical reaction complete faster? What conclusion do you draw?
3One glass holds 100 ml of hot water and another holds 100 ml of cold water, and a vitamin C capsule is put into each at the same time. In which glass does the reaction complete faster? What conclusion do you draw?
4What is meant by the rate of a chemical reaction? Give one example each of a fast and a slow reaction.
5How do the concentrations of reactants and products change during a chemical reaction?
6What is a catalyst? Distinguish between a positive catalyst and a negative catalyst with one example of each.
7Why does pressure affect the rate of reactions between gases but hardly affect reactions of solids and liquids?
8Why does powdered marble react with dilute hydrochloric acid faster than the same mass of marble chips?
9Give two examples of chemical reactions whose rate is affected by light.
10Hydrogen peroxide is sold in dark brown bottles with a little phosphoric acid added. Give reasons.
11Why does milk go sour faster in summer than in winter, and how does a refrigerator help?