C1 + C2 exam paper Flashcards
- An atom of aluminium has the symbol27
<span> 13 </span><span> Al </span>
a) Give the number of protons, neutrons and electrons in this atom of aluminium.
(b) Why is aluminium positioned in Group 3 of the periodic table?
Number of protons : 13
Number of neutrons: 14
Number of electrons: 13
It is in group 3 because it has 3 electrons in the outer shell
c) In the periodic table, the transition elements and Group 1 elements are metals.Some of the properties of two transition elements and two Group 1 elements are shown in the table below.
* *Transition elements_ _Group 1 elements**
* *Chromium Iron Sodium Caesium**
* *Melting point** 1857 1535 98 29
* *in 0C**
* *Formula of oxides** CrO FeO Na2O Cs2O
Cr2O3 Fe2O3
CrO2 Fe3O4
CrO3
Use your own knowledge and the data in the table above to compare the chemical and physical properties of transition elements and Group 1 elements.
PHYSICAL
Transition elements:__Group 1:
- high melting points - low melting points
- high densities -low densities
- strong, hard -soft
- *CHEMICAL**
- *Transition elements__Group 1**
- low reactivity - very reactive
- used as catalysts -not used as catalyst
- ions with different charges - white / colourless compounds
- coloured compounds - only forms a +1 ion
Q2) Rock salt is a mixture of sand and salt.
Salt dissolves in water. Sand does not dissolve in water. Some students separated rock salt.
This is the method used.
1. Place the rock salt in a beaker.
2. Add 100 cm3 of cold water.
3. Allow the sand to settle to the bottom of the beaker.
4. Carefully pour the salty water into an evaporating dish.
5. Heat the contents of the evaporating dish with a Bunsen burner until salt crystals start to
form.
(a) Suggest one improvement to step 2 to make sure all the salt is dissolved in the water.
(b) The salty water in step 4 still contained very small grains of sand.
Suggest one improvement to step 4 to remove all the sand.
(c) Suggest one safety precaution the students should take in step 5.
(d) Another student removed water from salty water using the apparatus in the figure below. SEE EXAM PAPER
Describe how this technique works by referring to the processes at A and B.
(e) What is the reading on the thermometer during this process?
a) heat, stir
b) filter
c) wear safety goggles, apron
d) evaporation at A
condensation at B
e) 100
Q3) This question is about halogens and their compounds.
The table below shows the boiling points and properties of some of the elements in Group 7 of the periodic table.
Element Boiling point in °C Colour in aqueous solution
Fluorine -188 colourless
Chlorine −35 pale green
Bromine X orange
Iodine 184 brown
(a) Why does iodine have a higher boiling point than chlorine?
Tick one.
Iodine is ionic and chlorine is covalent
Iodine is less reactive than chlorine
The covalent bonds between iodine atoms are stronger
The forces between iodine molecules are stronger
(b) Predict the boiling point of bromine.
(c) A redox reaction takes place when aqueous chlorine is added to potassium iodide solution. The equation for this reaction is:
Cl2(aq) + 2KI(aq) → I2 (aq) + 2KCl(aq)
What is the colour of the final solution in this reaction?
Tick one.
Brown, Orange, Pale green, Colourless
(d) What is the ionic equation for the reaction of chlorine with potassium iodide?
Tick one.
Cl2 + 2K → 2KCl
2I−+Cl2 → I2+2Cl−
I−+Cl → I+Cl−
I−+K+ → KI
(e) Why does potassium iodide solution conduct electricity?
Tick one.
It contains a metal
It contains electrons which can move
It contains ions which can move
It contains water
(f) What are the products of electrolysing potassium iodide solution? Tick one.
Product at cathode Product at anode
hydrogen iodine
hydrogen oxygen
potassium iodine
potassium oxygen
M3.(a) The forces between iodine molecules are stronger
(b) anything in range +30 to +120
(c) Brown
(d) 2I− + Cl2 → I2 + 2Cl−
(e) It contains ions which can move
(f) hydrogen iodine
Q4.Water from a lake in the UK is used to produce drinking water.
(a) What are the two main steps used to treat water from lakes?
Give a reason for each step.
Step 1 …………………………………………………………………………………………………. Reason ……………………………………………………………………………………………….
Step 2 ………………………………………………………………………………………………… Reason ……………………………………………………………………………………………….
(b) Explain why it is more difficult to produce drinking water from waste water than from water in lakes.
(c) Some countries make drinking water from sea water.
Complete the figure below to show how you can distil salt solution to produce and collect pure water.
Label the following: SEE PAPER
• pure water
• salt solution
(d) How could the water be tested to show it is pure?
Give the expected result of the test for pure water.
(e) Why is producing drinking water from sea water expensive?
M4 (a) filtration
or
by passing through filter beds to remove solids
sterilisation to kill microbes
allow chlorine
(b)water needs more / different processes
because it contains any two from:
• more organic matter
• more microbes
• toxic chemicals or detergents
(c) (as part of glassware attached to bung) salt solution in (conical) flask
or suitable alternative equipment, eg boiling tube
(at end of delivery tube)
pure water in test tube which must not be sealed
or suitable alternative equipment, eg, beaker, condenser
heat source (to heat container holding salt solution)
(d) determine boiling point,should be at a fixed temperature 100°C
(e) high energy requirement
Q5.This question is about magnesium.
(a) (i)
The electronic structure of a magnesium atom is shown below. SEE PAPER
electrons neutrons protons shells
Use the correct answer from the words above to complete each sentence.
The nucleus contains protons and ………………
The particles with the smallest relative mass that move around the nucleus are called ………………
Atoms of magnesium are neutral because they contain the same number of electrons and ………………
(ii) A magnesium atom reacts to produce a magnesium ion. Which diagram shows a magnesium ion?
SEE PAPER
(b) Magnesium and dilute hydrochloric acid react to produce magnesium chloride solution and hydrogen.
Mg(s) + 2 HCl(aq) MgCl2(aq) + H2(g)
(i) State two observations that could be made during the reaction.
1 ………………………………………………………………………………………………
2 ………………………………………………………………………………………………
(ii) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.
(2)
Describe a method for making pure crystals of magnesium chloride from magnesium and dilute hydrochloric acid.
In your method you should name the apparatus you will use.
You do not need to mention safety.
M5.(a)
(i) neutrons
this order only
electrons
protons
(ii) box on the left ticked
(b) (i) effervescence / bubbling / fizzing / bubbles of gas
do not accept just gas alone
magnesium gets smaller / disappears
allow magnesium dissolves
allow gets hotter or steam produced
ignore references to magnesium moving and floating / sinking and incorrectly named gases.
(ii)
The answer must include a way of ensuring the hydrochloric acid is fully reacted and a method of obtaining magnesium chloride crystals.
examples of the points made in the response:
• hydrochloric acid in beaker (or similar)
• add small pieces of magnesium ribbon
• until magnesium is in excess or until no more effervescence occurs *
• filter using filter paper and funnel
• filter excess magnesium
• pour solution into evaporating basin / dish
• heat using Bunsen burner
• leave to crystallise / leave for water to evaporate / boil off water
• decant solution
• pat dry (using filter paper).
Q6.This question is about atomic structure and elements.
(a) Complete the sentences.
(i) The atomic number of an atom is the number of ………………………………………………………………………………
(ii) The mass number of an atom is the number of ………………………………………………………………………………………
(b) Explain why an atom has no overall charge.
Use the relative electrical charges of sub-atomic particles in your explanation. …………………………………………………………………………………………………………………………………………………………………………………………
(c) Explain why fluorine and chlorine are in the same group of the periodic table. Give the electronic structures of fluorine and chlorine in your explanation. …………………………………………………………………………………………………………………………………………………………………………………………
(d) The diagram shows the electronic structure of an atom of a non-metal.
SEE PAPER
What is the chemical symbol of this non-metal? Tick ( ) one
Ar
O
S
Si
(e) When elements react, their atoms join with other atoms to form compounds. Complete the sentences.
(i) Compounds formed when non-metals react with metals consist of particles called ………………………………………………………………………………… .
(ii) Compounds formed from only non-metals consist of particles called ……………………………………………………….. .
M6.(a)
(i) protons
allow “protons or electrons”, but do not allow “protons and electrons”
(ii) protons plus / and neutrons
(b) (because the relative electrical charges are) −(1) for an electron and +(1) for a proton
allow electrons are negative and protons are positive
and the number of electrons is equal to the number of protons
if no other mark awarded, allow 1 mark for the charges cancel out
(c) (the electronic structure of) fluorine is 2,7 and chlorine is 2,8,7
allow diagrams for the first marking point
(so fluorine and chlorine are in the same group) because they have the same number of or 7 electrons in their highest energy level or outer shell
(d) S
(e) (i) ions
(ii) molecules
