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Flashcards in Kinetics Deck (9)
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1

Rate of Reaction

The decrease in the concentration of reactants per unit time, or the increase in the concentration of products per unit time

2

Ea

The minimum energy the colliding particles need in order to react

3

Reactions can be made faster in two ways:

1. Increasing collision frequency
2. Increasing fraction of successful collisions

4

The rate of a chemical reaction can be changed in a number of ways:

1. by changing the concentration of the reacting particles
2. by changing the pressure of the system (if some of the reacting particles are in the gas phase)
3. by changing the particle size (if some of the reacting particles are in the solid state)
4. by changing the temperature of the system
5. by adding a catalyst

5

An increase in concentration + pressure increases the rate of reaction because

the number of particles per unit volume increases so the collision frequency increases

6

A decrease in particle size increases the rate of reaction because

the surface area increases so the collision frequency increases

7

An increase in temperature increases the rate of reaction because

The mean collision energy of the particles increases so more of the particles have a collision energy greater than the activation energy so the fraction of successful collisions increases and the particles are moving faster so the collision frequency increases

8

A catalyst is a

Substance which changes the rate of a chemical reaction without itself being chemically altered at the end of the reaction.

9

A catalyst increases the rate of reaction because

The activation energy of the particles decreases so more of the particles have a collision energy greater than the activation energy so the fraction of successful collisions increases