Topic 5 & 6 - Groups in the Periodic Table and Rates of Reaction and Energy Changes COMPLETE PK Flashcards
1 What do atoms of the same element have in common?
their atomic number/number of protons
2 Roughly how many elements are found naturally?
90 to 100
3 In what order are elements arranged in the periodic table?
in order of increasing atomic number
4 What do you call the columns in the periodic table?
groups
5 What is special about the elements that are in the same group of the periodic table?
similar properties
6 What is similar about the electronic configuration of elements in the same group?
same number of outer electrons
7 What is formed when a group 1 element reacts with water?
an alkali/metal hydroxide + hydrogen
8 What is the charge on the ions of elements in group 1?
1+
9 The first two elements in group 1 are lithium and sodium. What is the third element?
potassium
10 What name is given to group 1 elements?
the alkali metals
11 What happens to the reactivity of the group 1 elements as you go down the group?
it increases
12 What is produced when lithium reacts with water?
lithium hydroxide and hydrogen
13 Why do alkali metals get more reactive as you go down the group?
the outermost electron is further and further away, and so more easily removed
14 What name is given to group 7 elements?
the halogens
15 State an example of a group 7 element.
one of: fluorine, chlorine, bromine, iodine or astatine
16 What is the state of a substance at room temperature, if it has a melting point of 7 °C and a boiling point of 59 °C?
liquid
17 What ion is in all acid solutions?
H+
18 Do metals usually form ionic compounds with other metals, non-metals, neither or both?
non-metals
19 State the formula of the compound formed when calcium reacts with bromine.
CaBr2
20 What is the name and colour of the only liquid halogen?
bromine, brown
21 What does chlorine look like?
pale green gas
22 How is the appearance of iodine different from that of the three halogens above it in group 7?
solid and darker/black in colour
23 Name the compound formed when hydrogen reacts with chlorine.
hydrogen chloride
24 What kind of solution is formed when hydrogen fluoride dissolves in water – acidic, neutral or alkaline?
acidic
25 Complete the equation: Ca(s) + Cl2(g) →
CaCl2(s)
26 What ions are present in potassium fluoride?
K+ and FI-
27 State one similarity in the electronic configurations of fluorine and chlorine.
same number of outer electrons
28 Describe the trend in reactivity of group 7 elements.
decreasing down the group
29 What type of reaction occurs between chlorine and potassium bromide?
displacement and redox
30 What is formed when chlorine water is added to sodium bromide solution?
sodium chloride + bromine
31 What type of reaction is the reaction between chlorine water and sodium bromide solution an example of?
displacement, redox
32 Fluorine atoms are more reactive than chlorine atoms. What does fluorine have fewer of that explains this?
electron shells
33 H Describe reduction in terms of electron transfer.
gain of electrons
34 Where is group 0 found in the periodic table?
last column on right-hand side
35 What name is given to group 0 elements?
the noble gases
36 Name a group 0 element.
one of: helium, neon, argon, krypton, xenon or radon
37 What is similar about the electronic configuration of all group 0 elements?
full outer shell
38 How are noble gases similar in terms of chemical properties?
all unreactive
39 Describe the trend in the boiling points of the elements, down group 0.
increasing
40 What happens to the reactants during a chemical reaction?
They are changed into new substances/products/used up.
41 What happens to the rate of most reactions as the reaction proceeds?
It slows down.
42 In reactions involving solutions, what happens to the rate if the concentrations at the start are decreased?
They become slower.
43 What size of solid lumps reacts fastest in chemical reactions: small, medium or large?
small
44 Apart from concentration and surface area, name one other variable that can change the speed of a chemical reaction.
temperature or pressure or catalyst
45 What happens in a precipitation reaction?
A solid forms.
46 What does it mean if effervescence is seen during a reaction?
A gas is being produced.
47 What happens to the concentration of reactants as a reaction proceeds?
It decreases.
48 What happens to the concentration of products as a reaction proceeds?
It increases.
49 Why is there a loss in mass during the reaction between calcium carbonate and hydrochloric acid?
A gas is given off/lost.
50 What usually happens to the rate of a reaction as the reaction proceeds?
It slows down.
51 What happens to the concentration of reactants as a reaction proceeds?
It decreases.
52 In a graph of concentration of products against time, how do you know when the reaction is finished?
The graph levels off.
53 A reaction is followed by measuring the volume of gas produced. What other measurement could be used?
measuring mass lost
54 What usually happens to the speed of a reaction as the temperature is decreased?
It gets slower.
55 How does increasing the concentration of a solution affect the rate of reaction?
It increases the rate.
56 What is the link between the size of the solid lumps and the surface area of a fixed mass of solid?
The smaller the lumps, the larger the surface area.
57 What type of solid lumps will react fastest?
the smallest lumps or powders
58 In reactions involving gases, how does gas pressure affect the reaction rate?
Increased pressure increases the rate.
59 What must the reacting molecules do for a reaction to occur?
They must collide with enough energy.
60 What has to happen before a reaction takes place?
Reacting molecules must collide with enough energy.
61 Describe two ways of measuring reaction rates in a reaction that produces a gas.
measuring volume of gas formed and mass lost by reactants
62 Explain how increasing concentrations increases the rate of a reaction.
More collisions occur.
63 What change in condition increases the speed of the reacting molecules?
increasing temperature
64 How can you increase the surface area of a solid?
Divide the solid into smaller pieces.
65 Explain how increasing the surface area of a solid increases the rate of reaction.
More collisions can occur.
66 Which change in condition only affects reactions involving gases?
pressure
67 What is the activation energy in a reaction?
minimum energy needed by reactants for them to react
68 What does a catalyst do?
speeds up a chemical reaction
69 What do you call a biological catalyst?
an enzyme
70 What do we call any substance that dissolves in a solvent to form a solution?
solute
71 What products form when an acid is neutralised by an alkali?
a salt and water
72 What do we call an insoluble substance that can form when two solutions are mixed?
precipitate
73 Which substance, polystyrene or copper, is the better heat insulator?
polystyrene
74 Energy is transferred by heating in three ways: convection, radiation and what else?
conduction
75 Zinc reacts with copper sulfate solution. What solid product forms?
copper
76 What gas is needed for fuels to burn?
oxygen
77 Fuels may ignite if a spark hits them. What else can make a fuel ignite?
a flame/heating strongly
78 Is energy transferred to or from the electrolyte during electrolysis?
to
79 Give two ways by which energy is transferred to the surroundings in an explosion.
two from: by heating, by sound, by light, by a force
80 What type of reaction takes in energy from the surroundings?
endothermic
81 What happens to the temperature of an acid when an alkali is added to it?
It goes up/increases.
82 What simple piece of apparatus is used to measure temperature?
thermometer
83 What unit is used for energy?
J/joule/kJ/kilojoule
84 What type of bond (ionic, covalent or metallic) exists between non-metals
covalent
85 In combustion reactions, is energy taken in from the surroundings or given out?
given out
86 How is energy transferred between reactants and surroundings during dissolving?
by heating
87 Which of these reactions, displacement or precipitation, always heats up the surroundings?
displacement
88 The temperature goes down when ammonium nitrate dissolves in water. Is this an exothermic process or an endothermic process?
endothermic
89 Energy is taken in so that bonds can be broken. Is this an exothermic or an endothermic process?
endothermic
- Burning methane - endothermic or exothermic?
exothermic
What are group number 1 elements of the periodic table also known as?
Alkali metals
What are group number 7 elements of the periodic table also known as?
Halogens
What are group number 8 elements of the periodic table also known as?
Noble gases
What are the metals in the middle of the periodic table known as?
The transition metals
Group 8 can also be called group _
0
Noble gases have a ____ outer shell
full
Noble gases are extremely reactive/unreactive
Unreactive
Give 2 uses of noble gases
Balloons and neon lights
Halogens are metals/non-metals
Non-metals
Halogens are ________ molecules
diatomic
What does being a diatomic molecule mean?
They are going to go around together in pairs
Give the formula for a diatomic molecule
Any of the following: Cl2, F2, Br2, etc
How can fluorine easily gain an electron?
By sharing it with another fluorine
Diatomic molecules want to gain _ electron
1
How can diatomic molecules gain an electron?
By sharing an electron with something that is the same
Halogens are highly reactice/unreactive
reactive
The most reactive halogens are at the bottom/top of the periodic table
Top
The boiling point increases as we move up/down group 7
Down
Elements at the top of group 7 have a low/high boiling point
Low
Elements at the bottom of group 7 have a low/high boiling point
High
When halogens react they loose/gain an electron
gain
Do halogens form +1 or -1 ions?
-1
Gaining an electron is reduction/oxidation
Reduction
How can you remember whether losing an electron is oxidation or reduction?
OIL RIG
Oxidation is Loss, Reduction is Gain
Halogens react rapidly and violently with group _ metals
1
Why do halogens react rapidly and violently with group 1 metals?
Because group 1 metals want to loose 1 electron
A more reactive element will displace a…
Less reactive element
Reactions when a more reactive element displaces a less reactive element are called…
displacement reactions
What are halogens mostly used for?
Sterilising things, such as chlorine in a swimming pool
Why are the most reactive halogens at the top?
That is where there is the least shielding between the electron they want to gain and the nucleus
Alkali metals react very violently with…
water
What happens when alkali metals react with water?
Different coloured flames are produced
Group _ metals are what are used to make the different colours in fireworks
1
The lilac flame from potassium is commonly used to make
fireworks
Alkali metals are s___ g___ metals
soft grey
Alkali metals are hard to cut/easy to cut
easy to cut
True/False: Alkali metals need to be kept in sand
False, they need to be kept in oil
Why do alkali metals need to be kept in oil?
So they don’t react with oxygen or the water in the air because it is a very violent reaction
When a metal reacts with oxygen it produces a…
metal oxide
When a metal reacts with water it produces a…
metal hydroxide
The dullness after an alkali metal has been cut is the metal oxide/hydroxide
Oxide
Metal hydroxide is acidic/alkaline
Alkaline
How can you see if something is an acid or alkali?
Use an indicator
Alkali metal + water -> metal hydroxide is a very endothermic/exothermic reaction
exothermic
Alkali metal + water releases a lot of heat and also releases…
hydrogen gas - this is what the fizzing is
The most reactive alkali metals are at the top/bottom of the periodic table
bottom
The least reactive alkali metals are at the top/bottom of the periodic table
top
Alkali metals at the bottom of the periodic table have high/low melting and boiling points
low
Alkali metals at the top of the periodic table have high/low melting points and boiling points
High
Alkali metals want to loose/gain an electron
Loose
Why are the alkali metals at the bottom of the periodic table the most reactive?
Because there is more shielding between the electron that they want to use and the positive nucleus in the middle
Give a way of following a reaction
Either loss of mass or production of gas
When is looking for a loss of mass a good way to follow a reaction?
When you have added something solid like marble chips into a liquid and you know that a gas is going to be produced
Why is looking for a loss of mass good when adding something solid to a liquid, knowing that a gas is going to be produced?
The gas will just go through the cotton wool at the top of the tube and out, and the mass will go down
Apart from measuring a loss of mass, what is a good way of following a solid + liquid -> gas reaction?
Collecting the gas in a measuring syringe or an inverted measuring cylinder
When measuring the rate of reaction, it is important to look carefully at the u____ used
units
There is a graph showing rate of reaction, with volume of CO2 produced (cm3) on the y axis and time in minutes on the x. What is this graph measuring?
cm3/minute
There is a graph showing rate of reaction, with mass in grams on the y axis and time in seconds on the x. What is this graph measuring?
g/s
What do you need to draw on a graph to find the rate of reaction at a particular point?
A tangent
Once you have drawn the tangent on a graph that you want to find the rate of reaction at a particular point of, what do you need to do?
Find the gradient of the tangent
When calculating rate of reaction at a certain point of a graph, what units do you need to use?
The ones on the graph
How do you find the gradient of a line?
Change in y / change in x
There will be the same/different rates of reaction at different points on a graph
Different
Sodium thiosulfate + hydrochloric acid
We can follow rate of reaction by looking at…
colour change taking place or how it changes from clear/colourless to opaque
Why do you need to constantly wash things out when doing sodium thiosulfate + hydrochloric acid?
So you’re not contaminating things
Why do you need to be careful not to go above 60 degrees when doing sodium thiosulfate + hydrochloric acid?
Nasty gases will start to come off at the end
Why is it important not to get anything on your hands when doing sodium thiosulfate + hydrochloric acid?
It will start to irritate your hands
Why is it important the same person measures rate of reaction (sodium thiosulfate + hydrochloric acid)?
So differences in people’s eyes don’t effect the results
One way that we can collect ___ is by using an inverted measuring cylinder and putting a d_______ t___ through there
Gas, delivery tube
When collecting gas using an inverted measuring cylinder and a delivery tube, one thing that we need to be careful about is the ___ that is aready in the measuring cylinder before/after you start the experiment
gas, before
When collecting gas using an inverted measuring cylinder and a delivery tube, the gas will move from the connical flask, through the delivery tube and in to the _________ ________
measuring cylinder
When collecting gas using an inverted measuring cylinder and a delivery tube, why do we collect the gas in the measuring cylinder?
So we can measure it
When collecting gas using an inverted measuring cylinder and a delivery tube, what is a common cause of errors?
The gas that is already in the cylinder before you start / gas is lost before you manage to get the bung on
When collecting gas using an inverted measuring cylinder and a delivery tube, when adding large marble chips, what starts to collect in the measuring cylinder?
Bubbles
When collecting gas using an inverted measuring cylinder and a delivery tube, why is gas sometimes lost?
Some can escape before you manage to get the bung on
When collecting gas using an inverted measuring cylinder and a delivery tube, what happens when you add powdered calcium carbonate?
It increases, bubbles are produced much faster and the measuring cylider fills up very quickly
When we have particles moving around at a low temperature, they are moving ______ with little/lots of energy
slowly litte
True/False: When particles at a low temperature collide, there is always a reaction
False, there is not always a reaction
When particles with high temperature, they move at ____ speed with lots of/little energy
high, lots of
True/False: When partices at high temperature collide, there is no reaction
False: There are a lot of reactions taking place
True/False: Temperature can effect rate of reaction
True
Sugar cubes in hot water will dissolve much faster/slower than sugar cubes in cold water
Faster
The higher the temperature, the faster/slower the rate of reaction will be
faster
Why does temperature increase rate of reaction?
Particles have more energy, so they can move around faster, which leads to more frequent and successful collisions
Temperature increases rate of reaction because particles have more ______, so they can move around ______, which leads to more ________ and successful collisions
energy, faster, frequent
When we have a lump of something, there is less/more surface area, so there is less/more space to react
less
When we have a powder of something, there is less/more surface area, so there is less/more space to react
more
The larger the surface area, the faster/slowe the rate of reaction
faster
Why does large surface area increase rate of reaction?
Because there are more particles available to react, leading to more successful collisions
The larger the surface area, the ______ the rate of reaction, this is because there are ____ particles availble to react, leading to more __________ collisions
faster, more, successful
When there are things at a high pressure / at a high concentration, they’re much more/less likely to bump in to each other and react
more
When there are things at a low concentration, they’re much more/less likely to bump in to each other and react
less
The higher the concentration/pressure, the ______ the rate of reaction
faster
Why is the rate of reaction faster when concentration/pressure is higher?
Here are more particles in a fixed volume, so there is a higher chance of successful collisions
What does a catalyst do?
Makes a reaction easier to happen, speeds up the reaction and lowers activation energy
True/False: An example of something a catalyst does is fixes reactants in place so it is easier for the other reactant to find it
True
True/False: Whenever there is a reaction, there is an activation energy
True
What does the hump on this graph represent?
The activation energy
Which side of the graph is the activation energy measured from? (Before the hump or after the hump)
After the hump
Catalysts increase/decrease activation energy
Decrease
What is the effect of activation energy being lowered by a catalyst?
It is easier for a reaction to take place
The blue line on this graph shows activation energy. The green line shows it after it has been _________, so it is easier for the reaction to take place.
catalysed
An endothermic reaction feels like it gets colder/hotter
colder
An exothermic reaction feels like it gets colder/hotter
Hotter
Endothermic reactions take energy in/give energy out
Take energy in
Exothermic reactions take energy in/give energy out
Give energy out
In an endothermic reaction, the energy of the products is ______ than the energy of the reactants
higher
Does this graph represent an endothermic or an exothermic reaction?
Endothermic
In an exothermic reaction, the products have _____ energy than the reactants
lower
Does this graph represent an endothermic or an exothermic reaction?
Exothermic
True/False: Electrolysis is an endothermic reaction
True
True/False: Burning is an endothermic reaction
False, it is an exothermic reaction
True/False: Neutralisation is an exothermic reaction
True
Bond breaking takes energy in/gives energy out
Takes energy in
Bond making takes energy in/gives energy out
Gives energy out
Burning hydrogen in water will give water.
What is the balanced equation for this reaction?
2H2 + O2 -> 2H2O
Burning hydrogen in oxygen will give water, calculate the energy change for this reaction
Bond energies:
H-H = 436kj/mol
O=O = 498 kj/mol
O-H = 464 kj/mol
-486kj/mol
If the calculated energy change for a reaction is negative, you know that the reaction is endothermic/exothermic
Exothermic
