Topic 6- The Rate and Extent Of Chemical Change Flashcards Preview

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Flashcards in Topic 6- The Rate and Extent Of Chemical Change Deck (14):
1

How are reaction rates explained?

By Collision Theory (the more collision there are the faster the reaction is.

2

What are the four things that the rate if reaction depends on?

1) Temperature
2) The concentration of a solution or the pressure of the gas
3) The surface Area
4) The presence of Catalysts

MORE COLLISIONS INCREASE THE RATE OF REACTION

3

What happens if you increase the temperature?

The rate will increase.
- The particles will move faster, they will collide more frequently.
- The faster they move the more energy they have, so more of the collisions will have enough energy to make the reaction happen.

4

What happens if you increase the concentration/pressure?

The rate will increase.
-There are more particles knocking about in the same volume of water.
-When the pressure is increased (gas), the same number of particles occupies a smaller space.

5

What happens if you increase the surface area?

The rate will increase.
-Increase of surface area-volume ratio, means that for the same volume of the solid, the particles around will have more area to work on.

6

What happens if you use a catalyst?

The rate will increase.

7

What are the three ways of measuring the rate if reaction?

1) Precipitation and Colour Change
2) Change in Mass
3)The volume of gas given off

8

Describe the precipitation and colour change...

Sodium Thiosulfate and HCI produce a cloudy precipitate.

9

Describe the change in mass experiment?

Magnesium and HCI react to produce H2 gas.

10

How to find the mean reaction rate from a graph...

Change in y / change in x

11

What happens when the reactants react?

Their concentration fall so the forward reaction will slow down, but as more and more products are made and their concentration rise, the backward reaction will speed up.

12

What is Le Chatelier's principle?

Is the idea that if you change the conditions of a reversible reaction at equilibrium, the system will try to counteract that change.

13

Where would the equilibrium move if you decrease the temperature?

toward the exothermic reaction (more products at the exothermic side)

14

Where would the equilibrium move if you increase the temperature?

toward the endothermic reaction (more products for the endothermic reaction)