Solutions

Question 1

What is required for a chemical reaction to take place?

Answer 1

Collision energy: activation energy, the minimum value of energy required for the reaction to take place
Collision geometry: modules must collide with the correct orientation

Question 2

What is a exothermic reaction?

Answer 2

Reaction where heat/energy is released

Question 3

What is needed for an exothermic reaction to take place?

Answer 3

Need to give it a bit of energy

Question 4

How much energy will the product of an exothermic reaction have?

Answer 4

Less than what it started out with

Question 5

How much energy will the product of an endothermic reaction have?

Answer 5

More energy than the reactants

Question 6

Which have higher activation energy, exothermic or endothermic reactions?

Answer 6

Endothermic reactions

Question 7

What factors affect rate of reaction?

Answer 7

Temperature: increase increases rate of reaction as particle kinetic energy is increased
Concentration: increase increases rate of reaction due to increase in correctly oriented collisions
Particle size: decrease in size increases rate of rector due to increase in surface area
Pressure ( only gasses) & volume: increase pressure or decrease volume increases rate of reaction
Catalyst: reduces activation energy

Question 8

Definition of equilibrium

Answer 8

At equilibrium the rate of the forward reaction = the rate of the reverse reaction

Question 9

What are the conditions for equilibrium reactions?

Answer 9

They are dynamic
Must occur in a closed system
Concentrations must be constant
No macroscopic changes take place

Question 10

What is the equilibrium constant?

Answer 10

Constant value for a certain reaction at a certain temperature

Question 11

Formula for equlibrium constant

Answer 11

Google the answer

Question 12

What is importat to remember when calculating equilibrium constant?

Answer 12

Units

Question 13

How do you figure out what direction a reaction will favor?

Answer 13

Calculating the possible equilibrium constant. If it is lower the one given the forward reaction wil be favored, if it is high the backwards will se favored

Question 14

What are the 3 possibilities for the solution of Q in comparison to k?

Answer 14

Q = k, equilibrium
Q > k, reaction go left, reverse reaction is favored
Q < k, reaction go right, forward reaction is favored

Question 15

What does Le Chatelier’s principle state?

Answer 15

If we change something in a reaction it will adjust so equilibrium is reached again

Question 16

How does added reactants change the equilibrium?

Answer 16

Reaction goes right, forward reaction is favoured

Question 17

How does added products change the equilibrium?

Answer 17

Equilibrium goes left, reverse reaction is favoured

Question 18

How does increase in pressure (decrease in volume) change the equilibrium? (Gasses only )

Answer 18

Side with less molecules is favoured

Question 19

How does decrease in pressure (increase in volume) change the equilibrium? (Gasses only)

Answer 19

Side with more molecules is favoured

Question 20

How does increase in temperature of an endothermic change the equilibrium?

Answer 20

Increase in product, reverse reaction is favoured

Question 21

How does increase in temperature of an exothermic change the equilibrium?

Answer 21

Decreases product & forward reaction is favoured

Question 22

What happens to the equilibrium constant k when temperature is changed?

Answer 22

It changes as well

Question 23

What is delta H in an endothermic reaction?

Answer 23

Positive

Question 24

What is delta H in an exothermic reaction?

Answer 24

Negative

Question 25

What effect does a catalyst have on the equilibrium?

Answer 25

It is reached faster, no effect on K (equilibrium constant)

Question 26

What is a homogenous mixture?

Answer 26

Uniform mixtures, no distinguishable components Ex : salt water

Question 27

What is a heterogenous mixture?

Answer 27

None uniform mixtures, distinguishable components Ex: blood

Question 28

Definition of solution

Answer 28

Homogenous mixture of 2 or more substances

Question 29

What are the 2 components of a solution?

Answer 29

Solvent & solute

Question 30

What is the solvent?

Answer 30

The thing that dissolves the other substance, what takes up the volume, larger mass or more moles

Question 31

What is the solute?

Answer 31

The thing that gets dissolved

Question 32

What phases can solutions be?

Answer 32

Gas, liquid or solid

Question 33

Definition of solubility

Answer 33

The amount of solute that will dissolve per volume of solvent

Question 34

What does it mean when something has a higher solubility

Answer 34

More will be dissolved

Question 35

What is solubility impacted by?

Answer 35

Molecular structure: some chemicals dissolve more than others Pressure (only for gas): increase in pressure increases gas solubility in a liquid Temperature: increased temperature decreases gas solubility in liquid. Increases in temperature increases solid/liquid solubility in liquid

Question 36

Rule about solubility

Answer 36

Like dissolves like

Question 37

Will a polar solute dissolve in a polar solvent?

Answer 37

Yes

Question 38

Will a non-polar solute dissolve in a non-polar solvent?

Answer 38

Yes

Question 39

Will a polar solute dissolve in a non-polar solvent?

Answer 39

No

Question 40

What is the saturation point?

Answer 40

Where the maximum solubility is reached

Question 41

What does saturation point depend on?

Answer 41

Temperature, pressure (gas) & chemical structure

Question 42

What happens to the freezing, melting & boiling point when adding a solute to water?

Answer 42

Decease in freezing & melting point, increase in boiling point

Question 43

What happens if you add salt to ice?

Answer 43

Makes it easier to melt

Question 44

What happens to the boiling and freezing point if you add salt to water?

Answer 44

Make it harder to freeze & require higher temperature to boil

Question 45

What is evaporation used for?

Answer 45

Separate a dissolved solid from a liquid, liquid is lost & solid retained

Question 46

What is distillation used for?

Answer 46

Separating 2 liquids

Question 47

How does distillation work?

Answer 47

Heating & cooling is used to separate 2 liquids, relies on a difference in boiling point

Question 48

What is filtration used for?

Answer 48

Separating solid from a liquid, only work on heterogenous mixtures

Question 49

What is chromatography used for?

Answer 49

Separating liquid-liquid, solid-liquid, solid-solid

Question 50

Rough steps of chromatography

Answer 50

Mixture is dissolved into a mobile phase (gas or liquid) Mobile phase flows through the chromatography system Mixture is separated onto the stationary phase (a piece of paper)

Question 51

What is centrifugation used for?

Answer 51

Separate solids from liquids or liquids from liquids, has to be a heterogeneous mixture

Question 52

What is the separation Method of chromatgraphy?

Answer 52

Polarity, size, binding affinity, boiling point or charge

Question 53

What is crystallization used for?

Answer 53

Separating a solid from a liquid in a homogeneous mixture

Question 54

What is important in order to be able to use crystallization?

Answer 54

The solid should have a crystalline structure

Question 55

What principle is crystallization based on?

Answer 55

That solubility of a solid in a liquid generally increases with temperature increase & decreases with a temperature decrease

Question 56

Is crystallisation a physical or chemical change?

Answer 56

Physical