Topic 7 - Groups In The Periodic Table, Rate Of Reaction, Energy Changes In Chemical Reactions

Question 1

spectator ion

Answer 1

an ion that doesn’t change during a chemical reaction

Question 2

activation energy

Answer 2

minimum energy with which particles must collide in order to cause a chemical reaction

Question 3

neutralisation reaction - what does it form

Answer 3

is when an acid and a base react to form water and a salt

Question 4

how is the periodic table arranged

Answer 4

so that elements in the same vertical column (group) have similar chemical properties

Question 5

what elements are in group 1

Answer 5

the alkali metals

Question 6

alkali metal properties

Answer 6

• low melting and boiling points
• soft
• easily cut
• low density
• very reactive
• readily form compounds with non-metals

Question 7

What non-metals do alkali metals react with

Answer 7

• oxygen
• chlorine
• water

Question 8

how does the reactivity differ in group 1

Answer 8

it increases as you go down the group

Question 9

what are the two products in an alkali metal + a non metal reaction

Answer 9

metal hydroxide + hydrogen

Question 10

observations: what happens when you react an alkali metal with water and how does the reactivity change as you go down the group

Answer 10

as you go down the group:
it starts bubbling then it fizzes about on the surface then it bursts into flames

Question 11

explain the trend of reactivity in group 1 using electron configuration

Answer 11

• group 1 atoms loose one electron when they react
• as you go down group 1, an electron shell is being added meaning the force of attraction between the positive nucleus and the outer electron shell decreases
• this makes it easier to remove the electron as there’s less force of attraction - this means they are more reactive

Question 12

what are the elements in group 7 called

Answer 12

the halogens

Question 13

what do all halogens exist as

Answer 13

all go round in pairs (diatomic molecules - molecules that contain only two atoms bonded to one another by a single covalent bond)

Question 14

halogen properties

Answer 14

• poor conductors of heat and electricity
• toxic and corrosive

Question 15

how does the reactivity differ in group 7

Answer 15

as you go down the group the reactivity decreases

Question 16

what are the products when halogens react with metals

Answer 16

metal halide (salt)

Question 17

what are the products when halogens react with hydrogen

Answer 17

hydrogen halide

Question 18

what happens in a displacement reaction

Answer 18

a more reactive element takes a place of less reactive element in an ionic compound

Question 19

explain the trend reactivity in group 7 using the electronic configuration

Answer 19

• group 7 atoms gain one electron when they react
• as you go down the group an electron shell is added and the distance between the outermost shell and the nucleus increases
• this means the force of attraction between the positive nucleus and an incoming negative electron decreases, so the ions do not form so easily and the reactivity decreases

Question 20

when is there a displacement of halogens

Answer 20

if a halogen is added to a solution of a compound containing a less reactive halogen it will react with the compound and form a new one

Question 21

redox

Answer 21

reduction and oxidisation occur at the same time

Question 22

when does a redox reaction take place

Answer 22

during a displacement reaction

Question 23

oxidisation

Answer 23

‘loss of electrons’

Question 24

reduction

Answer 24

‘gain of electrons’

Question 25

OILRIG

Answer 25

Oxidation Is Loss Reduction Is Gain

Question 26

what are the elements called in group 0/8

Answer 26

noble gases

Question 27

properties of elements in group 0

Answer 27

- are colourless - have very low melting and boiling points - a poor conductors of heat and electricity - INHERT (they do not react)

Question 28

why are noble gases unreactive

Answer 28

because their atoms already have a stable electronic configuration with a complete outer shell

Question 29

rate of reaction

Answer 29

the speed at which reactants are turned into products

Question 30

how can we control the rate of reaction

Answer 30

by altering variables

Question 31

independent variable

Answer 31

a variable that you change

Question 32

dependant variable

Answer 32

the variable that you are measuring and depends on the independent variable

Question 33

controlled variable

Answer 33

variables that remain the same

Question 34

in a reaction graph, what does it mean if the line is steep

Answer 34

the rate of reaction is fast (this is usually at the start of the reaction)

Question 35

in a reaction graph, what does it mean if the line goes straight

Answer 35

all the reactants have been used up and the reaction finishes

Question 36

how can you measure the rate of reaction

Answer 36

- collect gas given off - weigh the reaction - colour change

Question 37

equation work out the rate of reaction

Answer 37

quantity of products formed or quantity of reactants formed time taken time taken

Question 38

equation to work out the average rate at a certain time

Answer 38

volume / time

Question 39

how do you work out the actual rate at a particular time

Answer 39

- draw a tangent on the line of the time it asks - then work out the gradient of the tangent line - change in volume of product change in time

Question 40

collision theory

Answer 40

the reactant particles must collide or ‘bump’ together with enough energy to react —> the more particles they have means the more energy they can transfer during the collision

Question 41

activation energy

Answer 41

the minimum amount of energy needed for a reaction to occur is called its activation energy

Question 42

frequency of collisions

Answer 42

how often the particles collide

Question 43

what factors affect the rate of reaction

Answer 43

- concentration - temperature - particle size/surface area - presence of a catalyst

Question 44

explain how concentration affects the rate of reaction

Answer 44

increasing the concentration of solutions increases the rate of reaction because they are more reacting particles in the same volumes of collisions occur more often

Question 45

explain how surface area affects the rate of reaction

Answer 45

increasing the surface area to volume ratio increases the reaction because there is more surface for collisions to occur on and so collisions occur more often

Question 46

explain how pressure of gas affects the rate of reaction

Answer 46

increasing the pressure gas increases the reaction because the reacting particles are close together so collision are more often

Question 47

explain how temperature affects the rate of reaction

Answer 47

increasing the temperature increases the rate of reaction because the reaction particles speed up and have more energy; they therefore collide more often, and more particles have enough energy to react when they collide

Question 48

catalyst

Answer 48

a substance that speeds up a chemical reaction but is not used up in the process

Question 49

how to catalysts work

Answer 49

they lower the activation energy so more particles have enough energy to react

Question 50

how can you model the energy changes during a chemical reaction

Answer 50

reaction profile

Question 51

exothermic reaction

Answer 51

energy is transferred from the stores of energy in chemical bonds to the surroundings

Question 52

endothermic reaction

Answer 52

energy is transferred from the surroundings to stores of energy in chemical bonds

Question 53

in a reaction profile, if the reaction is exothermic, which line is drawn higher the reactants or the products

Answer 53

Question 54

in a reaction profile, if the reaction is endothermic, which line is drawn higher the reactants or the products

Answer 54

Question 55

what happens to the temperature in an exothermic reaction

Answer 55

temperature increases

Question 56

what happens to the temperature in an endothermic reaction

Answer 56

temperature decreases

Question 57

if the energy change is a positive number, what type of reaction is it

Answer 57

endothermic

Question 58

if the energy change is a negative number, what type of reaction is it

Answer 58

exothermic

Question 59

two types of exothermic reactions

Answer 59

- neutralisation (reaction between an acid and a base) - displacement (the reaction between a metal and a compound of a less reactive metal or between a halogen and a compound of a less reactive halogen)

Question 60

how can you model the activation energy

Answer 60

in a reaction profile by drawing a ‘hump’ between the reactants and the products

Question 61

BENDMEX

Answer 61

Breaking is ENDothermic Making is EXothermic

Question 62

what type of reaction is it if energy is transferred to the reactants to BREAK their bonds and why

Answer 62

endothermic because more energy is given out breaking bonds than is needed to make bonds

Question 63

what type of reaction is it if energy is transferred to the surroundings as bonds form (MAKE) and why

Answer 63

exothermic because more energy is given out making bonds than is needed to break bonds

Question 64

bond energy calculation meaning

Answer 64

the total amount of energy in that bond

Question 65

how to work out the energy change

Answer 65

1) work out the total energy of the bonds in the reactants (bonds broken) - you are given the energy each bond produces, you just have to add and times them accordingly) 2) work out the total energy of the bonds in the products (bonds made) - you are given how much energy each bond produces, you just have to add and times them accordingly) 3) then you do (bonds broken) - (bonds made) = total energy change —> breaking - making (BendMex)