Effects On Reactions Flashcards Preview

Chemistry > Effects On Reactions > Flashcards

Flashcards in Effects On Reactions Deck (41):
0

Universal indicator

Made of 6/7 indicators that change colour at different PH levels
Supplied as : a solution in ethanol / paper dipped in it and dried

1

Using universal indicator

Substance tested is dissolved in water, a drop of it is then placed onto PH paper
OR
A drop of universal indicator is dropped into the tested substance

A gas can be tested using damp PH paper

2

Bases

Chemical opposite to alkalis

3

Alkalis

Bases soluble in water

Often more harmful than acids

8-14 PH

4

Neutral

Neither acidic or alkaline

7

5

Acids

0-6

6

Titration

Method of finding the volume of a solution required to react with a certain volume of another

7

Acid alkali titration

How much acid to neutralise an alkali

8

Acid-alkali titration method

Out 25.0 cm^3 of alkali solution into a flask
Few drops of methyl orange added
Note reading of acid in a burette
Add acid to alkali until indicator changes colour
Note final acid reading in burette
Substrate initial reading from final
-> Amount of acid required to neutralise 25.0cm^3 of the alkali

9

State of division

the smaller the pieces of solid -> the larger the overall surface area

More particles of the solid exposed to the other reactants

Grinding the solid to a powder has the most dramatic effect

10

Temperature of reaction

Increases average kinetic energy of the reactant particles

More of the collisions that take place will have the necessary activation energy to react

More successful reactions per second

11

Concentration of reactants

Increases the number of reactants

Reacting particles will collide more often

More successful collisions per second

12

Factors that affect rate of reaction

The concentration of a reaction

Temperature at which the reaction takes place

State of division of a solid reactant

13

Rate of reaction

Change of concentration of a reactant / time

14

Rate of reaction depends on

Concentration not amount

Particles must collide for a reaction to occur

Colliding particles must have enough energy to react
(activation energy) (successful collisions)

To increase the rate, the frequency of successful collisions must increas

15

Controlling the equilibrium

If forward reaction is exothermic
Backwards reaction is endothermic

16

More product

Equilibrium shift to the right

17

More reactant

Equilibrium shifts to the left

18

Dynamic equilibrium features

Rate of forward reaction = rate of backwards reaction

Amount of reactants and products remain constant

19

Dynamic equilibrium

If a reversible reaction is carried out in a closed reaction container
Then the reaction is able to reach a position of Dynamic equilibrium

20

Ammonia dynamic equilibrium

Hydrogen + nitrogen Ammonia

Ammonia can't escape, will decompose into hydrogen + nitrogen

Rate of forward reaction will stop the rate of backwards reaction
They will then become equal

21

Copper (ii) sulfate crystals dynamic equilibrium

Copper (ii) sulfate crystals heated in a test tube
Crystals turn to powder, water collects on top

Crystals -> hydrated copper (ii) sulfate
Contains water of crystallisation

Heated to lose this water
->turns to Anhydrous copper (ii) sulfate

Reaction is reversible

22

Catalyst

A substance that increases the rate of reaction of a chemical reaction, but it is chemically unchanged at the end

Allow lower temperatures / pressures to be used

23

What catalysts do

Provide an alternative pathway for the reaction
This pathway has a lower activation energy

More of the collisions taking place will have the necessary activation energy

More successful collisions per second


24

Exothermic

- enthalpy
Energy given out
Rise in temperature

25

Endothermic

+enthalpy
Energy taken in
Fall in temperature

26

Heat given out

Mass of solution x specific heat capacity of solution x temperature rise

27

What is an acid

An acid is a substance that dissolves in water to produce hydrogen ions

28

A salt compound

Hydrogen ions (from dissolved acid) replaced by
Ammonium or metal ions

29

You must react the dilute acid with what to replace the hydrogen ions by a metal ion

Metal
Base
metal carbonate

30

Litmus paper turns red

O-5
Acid

31

Litmus turns purple

5-8
Neutralish

32

Litmus turns blue

8-14
Alkali

33

Methyl orange turns red

0-3
Very Alkali

34

Methyl orange turns orange

3-5
Fairly acidic

35

Methyl orange turns yellow

5-14
Neutralise to alkaline

36

Phenolphthalein turns colourless

0-10
Acidic to neutralish

37

Phenolphthalein turns red

10-14
Very alkaline

38

Equilibrium
Endothermic

Shifts to right

39

Equilibrium
Exothermic

Shifts to left

40

Equilibrium pressure

Makes equilibrium shift to the area with the less particles