The Rate And Extent Of Chemical Change

Question 1

What is the rate of reaction?

Answer 1

A MEASURE of HOW QUICKLY a REACTANT is USED UP or how quickly a PRODUCT is FORMED

Question 2

What two things need to happen for a reaction to happen?

(Collision Theory)

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Answer 2

-REACTANT particles MUST COLLIDE with EACHOTHER

-The particles must have ENOUGH ENERGY to REACT

Question 3

What is a successful collision defined by?

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Answer 3

A COLLISION that PRODUCES a REACTION

Question 4

What is activation energy?

**

Answer 4

The MINIMUM AMOUNT of ENERGY needed for a COLLISION to be SUCCESSFUL

Question 5

Why is activation energy different for different reactions?

Question 6

Describe the three stages of chemical reaction according to Collision Theory

(BLURT QUESTION)

Answer 6

1. TWO PAIRS of particles MOVE TOWARDS EACH OTHER
2. The PAIRS COLLIDE and REFORM so that EACH MEMBER of the ORIGINAL PAIR JOINS with a MEMBER of the OTHER PAIR
3. Two NEW PAIRS are FORMED and EACH PAIR MOVES AWAY from EACH OTHER

Question 7

How do you calculate the mean rate of reaction?

**

Answer 7

-QUANTITY of REACTANT USED / TIME Taken

-QUANTITY of PRODUCT FORMED / TIME taken

Question 8

Why is measuring mass important when a reaction forms carbon dioxide?

Answer 8

CARBON DIOXIDE is KNOWN to LEAVE the CONTAINER which AFFECTS RESULTS

Question 9

Why is measuring mass not suitable for hydrogen?

Question 10

What are the units for the rate of mass change?

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Answer 10

G/s or G/min

Question 11

When is measuring the change in volume useful?

**

Answer 11

When a GAS LEAVES a CONTAINER

Question 12

How is the change in volume measured?

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Answer 12

Using an UPSIDE-DOWN BURETTE or a MEASURING CYLINDER

Question 13

What is an upside down burette?

Question 14

Describe one way to measure volume change

(BLURT METHOD)

Question 15

Describe a second way to measure volume change

(BLURT QUESTION)

Question 16

What are the units for change in volume?

**

Answer 16

Cm^3 per s^-1 or cm^3 per min^-1

Question 17

What kind of graph can the rate of reaction be plotted against?

Answer 17

A TOTAL MASS / VOLUME (Y-AXIS)
against TIME (X-AXIS) graph

Question 18

What is the gradient of a volume/mass to time graph equal to?

Answer 18

The RATE of REACTION

Question 19

What does the horizontal line tell you?

Answer 19

When the REACTION FINISHES

Question 20

What does the steepness of the line tell you?

**

Answer 20

The STEEPER the LINE the GREATER the RATE of REACTION

Question 21

What is until for rate of reaction?

Answer 21

Mol / s^-1

Question 22

How do you calculate the mole?

**

Answer 22

Mass / Mr

Question 23

How does the frequency of successful collisions affect the rate of reaction?

**

Answer 23

The GREATER the FREQUENCY of SUCCESSFUL COLLISIONS the GREATER the RATE of REACTION

Question 24

How does increasing concentration or pressure affect the rate of reaction in a gas?

**

Answer 24

INCREASES the RATE of REACTION by making PARTICLES MORE CROWDED

Question 25

What is mean energy? ***

Answer 25

The AVERAGE CAPACITY of a SYSTEM to DO WORK

Question 26

Why does the mean energy of particles not change even though the rate of reaction increases? ***

Question 27

What kind of graph can the total amounts of products be plotted against? **

Answer 27

A TOTAL MASS / VOLUME ( Y AXIS) against TIME (X AXIS) GRAPH

Question 28

What is a tangent? ***

Question 29

How do you draw the tangent? ***

Question 30

Why do larger lumps have smaller surface to volume ratios than small lumps? ***

Question 31

What happens to a large lump’s volume when it is divided or ground into powder? ***

Answer 31

It STAYS the SAME because VOLUME is just the MEASURE of the AMOUNT of SPACE its OBJECT can OCCUPY

Question 32

What happens to the amount of exposed surface when a large lump is divided or ground into powder? ***

Answer 32

The AREA of EXPOSED SURFACE INCREASES

Question 33

What happens to a the surface area to volume ratio of a large lump when it is divided or ground into powder? **

Answer 33

INCREASES

Question 34

How does increasing the surface area to volume ratio affect the rate of reaction? (BLURT QUESTION) ***

Answer 34

-INCREASES the RATE of REACTION -The VOLUME STAYS the SAME -The AREA of EXPOSED SURFACE INCREASES -The SURFACE AREA to VOLUME RATIO INCREASES

Question 35

How does temperate increase the energy of collisions? **

Answer 35

INCREASES the ENERGY of COLLISIONS

Question 36

What is a catalyst? ***

Answer 36

A SUBSTANCE which INCREASES the RATE of REACTION. Its is NOT USED OP or CHEMICALLY CHANGED and it does NOT ALTER the PRODUCTS of the REACTION

Question 37

Why doesn’t a catalyst change or “use up” during a reaction? ***

Answer 37

CATALYSTS only SPEND a SHORT AMOUNT of TIME with the CHEMICALS

Question 38

Why is only a small mass of catalyst needed to increase the rate of reaction? (BLURT QUESTION) ***

Answer 38

CATALYSTS are NOT USED UP which means each MOLECULE can INTERACT with MANY MOLECULES CATALSYTS give the PARTICLES the ENERGY they NEED to INCREASE the RATE of REACT

Question 39

Why do not all substances have suitable catalysts? *** (BLURT QUESTION)

Question 40

What are some examples of different types of catalysts? *** (BLURT QUESTION)

Answer 40

-Enzymes -Hydrochloric Acid -Platinum

Question 41

Why do different catalysts catalyse different reactions? *** (BLURT QUESTION)

Answer 41

DIFFERENT CATALYSTS have SPECIFIC PROPERTIES that MATCH the NEEDS of PARTICULAR REACTIONS

Question 42

How does a catalyst lower activation energy?

Answer 42

A CATALYST PROVIDES an AN ALTERNATE REACTION REACTION PATHWAY that has a LOWER ACTIVATION ENERGY

Question 43

How does the use of a catalyst affect the number of collisions? ***

Answer 43

Does NOT CHANGE the FREQUENCY of COLLISIONS however it does INCREASE the NUMBER of SUCCESSFUL COLLISIONS due to a LOWER ACTIVATION ENERGY

Question 44

Describe the difference between the reaction profiles of a reactant with a catalyst and then without a catalyst?

Answer 44

The CURVE is SHORTER since the ACTIVATION ENERGY is LESS

Question 45

What is a reversible reaction?

Answer 45

A CHEMICAL REACTION which SWINGS BOTH WAYS

Question 46

Which direction does the arrow for a forward reaction point?

Answer 46

RIGHT

Question 47

What direction do the arrows point for a backward reaction?

Answer 47

LEFT

Question 48

How can the proportion of reactants and products be changed by altering reaction conditions?

Answer 48

Changing TEMP, PRESSURE or using CATALYSTS

Question 49

What is an example of a reaction condition which would decrease the amount of reactants / products?

Answer 49

DECREASING the TEMPERATURE

Question 50

What is an example of a reaction condition which would increase the amount of reactants/products?

Answer 50

INCREASING the TEMPERATURE

Question 51

What happens during energy changes during a reversible reaction?

Answer 51

If a REACTION is EXOTHERMIC in ONE DIRECTION it will be ENDOTHERMIC in THE OTHER DIRECTION

Question 52

What does ‘hydrated’ mean?

Answer 52

Containing WATER of CRYSTALLISATION

Question 53

Describe the structure of copper sulfate

Answer 53

A CRYSTAL, IONIC LATTICE

Question 54

How is water removed from copper sulfate?

Answer 54

HEAT

Question 55

What is left behind after heating copper sulfate?

Answer 55

WHITE, ANHYDROUS COPPER SULFATE

Question 56

What does anhydrous mean?

Answer 56

NOT HYDRATED or CONTAINING NO WATER

Question 57

What type of reaction is the forwards reaction?

Answer 57

ENDOTHERMIC

Question 58

What type of reaction is the backwards reaction?

Answer 58

EXOTHERMIC

Question 59

What happens when you add water again to the heated solution of copper sulfate?

Answer 59

It’s REHYDRATED