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Understanding Rates of Chemical Reactions

Learn about reaction rates and factors affecting them, including collision energy, concentrations, temperature, and catalysts. Explore reaction rate formulas and equilibrium expressions in chemistry. Calculate reaction rates using concentration data.

kennan-ferguson
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Understanding Rates of Chemical Reactions

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  1. R a t e s O f C h e m i c a l R e a c t i o n s

  2. R e a c t i o n R a t e F o r a r e a c t i o n t o o c c u r , p a r t i c l e s m u s t c o m e t o g e t h e r w i t h e n o u g h e n e r g y t o c a u s e a c h a n g e i n t h e e l e c t r o n c l o u d s o f a t o m s .

  3. R e a c t i o n R a t e • I f t h e c o l l i s i o n d o e s n ‘ t h a v e e n o u g h e n e r g y , t h e p a r t i c l e s b o u n c e a w a y w i t h n o c h a n g e . • I f t h e c o l l i s i o n h a s e n o u g h e n e r g y , a r e a c t i o n w i l l o c c u r .

  4. R e a c t i o n r a t e i s d e f i n e d a s : • T h e r a t e o f d i s a p p e a r a n c e o f o n e o f t h e r e a c t a n t s . • T h e r a t e o f a p p e a r a n c e o f o n e o f t h e p r o d u c t s . • T h e r a t e o f c h a n g e o f c o n c e n t r a t i o n i n a c o n s t a n t v o l u m e p r o c e s s .

  5. R e a c t i o n R a t e T h e u n i t s f o r r e a c t i o n r a t e a r e : m o l e / d m 3 s e c o n d

  6. R e a c t i o n R a t e F a c t o r s a f f e c t i n g r e a c t i o n r a t e : • N a t u r e o f R e a c t a n t s • B o n d A r r a n g e m e n t • I o n s o r M o l e c u l e s • C o n c e n t r a t i o n • T e m p e r a t u r e • C a t a l y s i s

  7. R e a c t i o n R a t e • A c t i v a t i o n E n e r g y • T h e e n e r g y n e e d e d t o s t a r t a c h e m i c a l r e a c t i o n . • T h e e n e r g y n e e d e d t o f o r m a n a c t i v a t e d c o m p l e x .

  8. R e a c t i o n R a t e • A c t i v a t e d C o m p l e x • A g r o u p o f m o l e c u l e s t h a t h a v e c o l l i d e d w i t h e n o u g h e n e r g y t o c a u s e a c h a n g e i n t h e i r e l e c t r o n c l o u d s , c a u s i n g a n e x c i t e d s t a t e .

  9. R e a c t i o n R a t e • C o n c e n t r a t i o n

  10. R e a c t i o n R a t e • T e m p e r a t u r e A n i n c r e a s e i n t e m p e r a t u r e c a u s e s m o r e p a r t i c l e s t o a t t a i n a c t i v a t i o n e n e r g y .

  11. R e a c t i o n R a t e • C a t a l y s i s • A c a t a l y s t c h a n g e s t h e r e a c t i o n m e c h a n i s m t o r e q u i r e a l o w e r a c t i v a t i o n e n e r g y .

  12. R e a c t i o n R a t e T h e R a t e E x p r e s s i o n f o r a r e a c t i o n i s e x p r e s s e d a s t h e s p e c i f i c r a t e c o n s t a n t , k , t i m e s t h e p r o d u c t o f t h e c o n c e n t r a t i o n s o f t h e r e a c t a n t s . r a t e = k [a ] [ b ]

  13. R e a c t i o n R a t e For the reaction, 2NO + Br2 --> 2NOBr2 , the k is 0.8 dm6 / mole2. sec. If the initial concentration of NO was 1.4M, what initial concentration of Br2 would produce NOBr at an initial rate of 0.75 moles/dm3/sec?

  14. R e a c t i o n R a t e R a t e = k [ N O ] [ B r 2 ] [ B r 2 ] = R a t e k [ N O ]

  15. R e a c t i o n R a t e M o s t r e a c t i o n s g o t o c o m p l e t i o n , t h a t i s , t h e y p r o c e e d u n t i l a l l o f o n e o f t h e r e a c t a n t s i s u s e d c o m p l e t e l y a n d t h e r e a c t i o n s t o p s .

  16. R e a c t i o n R a t e S o m e t i m e s , t h e p r o d u c t s o f a r e a c t i o n w i l l r e a c t w i t h e a c h o t h e r c a u s i n g t h e r e a c t i o n t o r e v e r s e i t s d i r e c t i o n . T h i s i s a R e v e r s i b l e R e a c t i o n

  17. R e a c t i o n R a t e R e v e r s i b l e r e a c t i o n s c a n r e a c h e q u i l i b r i u m . T h i s m e a n s t h e r e a c t i o n i s c o n t i n u i n g a t t h e s a m e r a t e i n b o t h d i r e c t i o n s .

  18. R e a c t i o n R a t e E q u i l i b r i u m e x p r e s s i o n : [ P r o d u c t s ] K e q = [ R e a c t a n t s ] T h e e x p o n e n t s a r e t h e s a m e a s t h e c o e f f i c i e n t s i n t h e c h e m i c a l e q u a t i o n

  19. E n d R e a c t i o n R a t e s

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