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Chemistry GCSE > Rate Of Reaction > Flashcards

Flashcards in Rate Of Reaction Deck (15):
1

What is the rate of a chemical reaction?

How fast the reactants are turned into products

2

What is the calculation for the rate of reaction?

amount of reactant used or amount of product formed

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time

 

units: g/s or cm3/s

3

How can rate of reaction be measured?

  • Mass of reaction mixture
  • Volume of gas given off
  • Light transmitted through solution

→ measures changes over time "quantative data"

→ cross method is subjective

4

What are the five things that affect the rate of reaction?

  • concentration of solutions
  • pressure of gas
  • temperature
  • surface area (of solids)
  • catalysts (ish)

5

Describe the collision theory

Reactions only take place when the particles that make up the reactants collide with enough energy 

6

What is activation energy?

the minimum amount of energy that particles must have when they collide before they can react

7

How does a higher concentration of a solution increase the rate of reaction? 

There are more particles in the same volume to react with so there is an increased collisioin frequency

8

How does incresing the pressure of the reactants in a gas reaction increase the reaction rate?

It squashed the gas particles closer together so there are more particles in the given vollume, causing an increased collision frequency

9

How does a larger surface area increase the rate of reaction?

There are more of the reactant particles exposed to react with so there is a greater collision frequency

10

How does a higher temperature increase the rate of reaction?

  • Greater collision frequency → more energy = move faster
  • More successful collisions → more particles have required activation energy

11

What is a catalyst?

A catalyst is a substance that increases the rate of a reaction without being chemically changed or used up by the end of the reaction

12

How does a catalyst increase the rate of reaction?

It provides an alternate pathway for a reaction that has a lower activation energy. Thus more particles have the required Efor a successful collsion

13

How do catalysts help reduce costs in industrial reactions?

  • Lower temperautre → less fossil fuels used
  • Small amount used, doesn't get used up
  • Higher yield per unit time → increased productivity

14

What are some disadvantages of using a catalyst in an industrial process?

  • Expensive
  • Specific → different reactions need different catalysts
  • Need to be regularly cleaned

15

(opt) Give some examples of catalysts

  • Iron → Haber Process, produces ammonia
  • Nickel → hydrogenation of oils, forms margarine
  • Platinum → car catalytic convertors, produces CO2, N2 and water                          vapour