1. Chemistry 12 Unit 1

2.  Chemical kinetics is the study of the rates of chemical reactions 4 Fe (s) + 3 O 2(g)  2 Fe 2 O 3(s) 2 H 2(g) + O 2(g)  2 H 2 O (g) eg: Ca (s) + 2 H 2 O (l)  Ca(OH) 2(s) + H 2(g)

3. The rate of any reaction is measured as the change in some quantity per time. 1.Measuring Rates of Chemical Reactions Try to use a quantity that is easy to monitor. eg:From the previous reactions you might use: (what happens to the total mass of the system?)

4. eg:If 2.0 g of rust is produced in 5.0 yr, what is the rate of rust produced in g/d? eg:If 2.5 L of H 2 is produced in 1.5 min, what is the rate of H 2 produced in mL/s?

5. eg:In a particular reaction, the concentration of HCl decreases from 1.00 M to 0.50 M in 3.0 min. What is the rate of this reaction in terms of concentration change?

6. Practice Problem: Sodium carbonate reacts with hydrochloric acid producing table salt, water and a non-combustible gas. The following data was obtained: Time (s)Volume of gas (mL) 5.012 10.025 15.037 20.049 25.060 30.068 a)Write the balanced chemical equation. b)Calculate the rate of production of gas from 5 to 15 seconds. c)Calculate the overall rate of gas production at 30 seconds. d)Calculate c) in mol/min assuming the reaction took place at STP. e)Calculate the mass of sodium carbonate used up after 30 s. f)Calculate the rate of the consumption of HCl in moles per second. g)Try to explain why the reaction slows down slightly over time.