1. Chem 1310: Introduction to physical chemistry Part 2: exercise 22, p658 NOBr formed from NO and Br 2

2. 2 NO + Br 2  2 NOBr Experimentally: first-order in Br 2, second-order in NO a) What is the rate law? b) What happens if we triple [Br 2 ]? c) What happens if we double [NO]? *) What happens if we compress the system from a volume of 1 L to 0.1 L?

3. NOBr formed from NO and Br 2 First-order in Br 2, second-order in NO What is the rate law? First-order in [Br 2 ]: rate  [Br 2 ] (all other things being constant) Second-order in [NO]: rate  [NO] 2 (all other things being constant) Overall: rate  [Br 2 ][NO] 2 or rate = k [Br 2 ][NO] 2

4. NOBr formed from NO and Br 2 rate = k [Br 2 ][NO] 2 What happens if we triple [Br 2 ]? [Br 2 ] new = 3 [Br 2 ] old

5. NOBr formed from NO and Br 2 rate = k [Br 2 ][NO] 2 What happens if we double [NO]? [NO] new = 2 [NO] old

6. NOBr formed from NO and Br 2 rate = k [Br 2 ][NO] 2 What happens if we reduce the volume from 1 L to 0.1 L? [NO] new = 10 [NO] old, [Br 2 ] new = 10 [Br 2 ] old Third-order overall