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

1
Q

spectator ion

A

an ion that doesn’t change during a chemical reaction

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2
Q

activation energy

A

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

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3
Q

neutralisation reaction

A

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

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4
Q

how is the periodic table arranged

A

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

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5
Q

what elements are in group 1

A

the alkali metals

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6
Q

alkali metal properties

A
  • low melting and boiling points
  • soft
  • easily cut
  • low density
  • very reactive
  • readily form compounds with non-metals
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7
Q

What non-metals do alkali metals react with

A
  • oxygen
  • chlorine
  • water
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8
Q

how does the reactivity differ in group 1

A

it increases as you go down the group

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9
Q

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

A

metal hydroxide + hydrogen

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10
Q

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

A

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

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11
Q

explain the trend of reactivity in group 1 using electron configuration

A
  • 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
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12
Q

what are the elements in group 7 called

A

the halogens

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13
Q

what do all halogens exist as

A

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

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14
Q

halogen properties

A
  • poor conductors of heat and electricity
  • toxic and corrosive
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15
Q

how does the reactivity differ in group 7

A

as you go down the group the reactivity decreases

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16
Q

what are the products when halogens react with metals

A

metal halide (salt)

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17
Q

what are the products when halogens react with hydrogen

A

hydrogen halide

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18
Q

name the elements in group 1 in order of ascending reactivity

A

lithium (Li)
sodium (Na)
potassium (K)
rubidium (Rb)
caesium (Cs)
francium (Fr)

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19
Q

what happens in a displacement reaction

A

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

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20
Q

name the elements in group 7 in order of decreasing reactivity

A

fluorine (F)
chlorine (Cl)
bromine (Br)
iodine (I)
astatine (At)

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21
Q

explain the trend reactivity in group 7 using the electronic configuration

A
  • 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 at attraction between the positive nucleus and an incoming negative electron decreases, so the ions do not form so easily and the reactivity decreases
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22
Q

when is there a displacement of halogens

A

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

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23
Q

redox

A

reduction and oxidisation occur at the same time

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24
Q

when does a redox reaction take place

A

during a displacement reaction

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25
Q

oxidisation

A

‘loss of electrons’

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26
Q

reduction

A

‘gain of electrons’

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27
Q

OILRIG

A

Oxidation
Is
Loss
Reduction
Is
Gain

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28
Q

what are the elements called in group 0/8

A

noble gases

29
Q

properties of elements in group 0

A
  • are colourless
  • have very low melting and boiling points
  • a poor conductors of heat and electricity
  • INHERT (they do not react)
30
Q

why are noble gases unreactive

A

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

31
Q

rate of reaction

A

the speed at which reactants are turned into products

32
Q

how can we control the rate of reaction

A

by altering variables

33
Q

independent variable

A

a variable that you change

34
Q

dependant variable

A

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

35
Q

controlled variable

A

variables that remain the same

36
Q

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

A

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

37
Q

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

A

all the reactants have been used up and the reaction finishes

38
Q

how can you measure the rate of reaction

A
  • collect gas given off
  • weigh the reaction
  • colour change
39
Q

equation work out the rate of reaction

A

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

40
Q

equation to work out the average rate at a certain time

A

volume / time

41
Q

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

A
  • 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
42
Q

collision theory

A

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

43
Q

activation energy

A

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

44
Q

frequency of collisions

A

how often the particles collide

45
Q

what factors affect the rate of reaction

A
  • concentration
  • temperature
  • particle size/surface area
  • presence of a catalyst
46
Q

explain how concentration affects the rate of reaction

A

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

47
Q

explain how surface area affects the rate of reaction

A

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

48
Q

explain how pressure of gas affects the rate of reaction

A

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

49
Q

explain how temperature affects the rate of reaction

A

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

50
Q

catalyst

A

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

51
Q

how to catalysts work

A

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

52
Q

how can you model the energy changes during a chemical reaction

A

reaction profile

53
Q

by using a catalyst explain how is the reaction faster

A

nice less energy is needed to start the reaction more reactant molecules have enough energy so more collisions are successful

54
Q

exothermic reaction

A

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

55
Q

endothermic reaction

A

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

56
Q

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

A

the reactants as energy is given out - energy goes from high to low

57
Q

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

A

the products as energy is taken in - energy goes from low to high

58
Q

in a reaction if the temperature increases what type of reaction is it

A

exothermic (energy is transferred to the surroundings)

59
Q

in a reaction if the temperature decreases what type of reaction is it

A

endothermic (energy is transferred to the object)

60
Q

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

A

endothermic

61
Q

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

A

exothermic

62
Q

two types of exothermic reactions

A
  • 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)
63
Q

how can you model the activation energy

A

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

64
Q

BENDMEX

A

Breaking is
ENDothermic
Making is
EXothermic

65
Q

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

A

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

66
Q

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

A

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

67
Q

bond energy calculation meaning

A

the total amount of energy in that bond

68
Q

how to work out the energy change

A

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)