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The diagram shows the structures of five substances, A, B, C, D and E.
[Image of structures: A, B, C, D, E]
Answer the following questions using only the structures in the diagram.
Each structure may be used once, more than once or not at all.
(a) Which structure, A, B, C, D or E,
(i) is a diatomic molecule, ............................................................. [1]
(ii) contains ions, ................................................................... [1]
(iii) decolourises aqueous bromine, ........................................... [1]
(iv) conducts electricity when molten, ......................................... [1]
(v) contains atoms of two different halogens? ............................ [1]
(b) Bromine is an element.
What is meant by the term element?
........................................................................................................... [1]
(c) Bromine melts at $-7 \degree C$ and boils at $59 \degree C$.
What is the physical state of bromine at $-15 \degree C$?
Explain your answer.
........................................................................................................... [2]
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The table shows the composition of the atmosphere of the planet Neptune.
[Table_1]
(a) Complete the table to calculate the percentage of methane in Neptune’s atmosphere. [1]
(b) Describe how Neptune’s atmosphere differs from the Earth’s atmosphere. Give three differences.
1 .................................................................................................................................................
........................................................................................................................................................
2 .................................................................................................................................................
........................................................................................................................................................
3 .................................................................................................................................................
........................................................................................................................................................ [3]
(c) Methane is a covalent compound.
Complete the diagram to show
• the arrangement of electrons in a molecule of methane,
• the symbols of the atoms present.
Show outer shell electrons only.
[2]
(d) Isotopes of hydrogen are present in Neptune’s atmosphere.
(i) What is meant by the term isotopes?
........................................................................................................................................................
........................................................................................................................................................ [1]
(ii) An atom of hydrogen has three nucleons.
Deduce the number of protons and neutrons present in one atom of this isotope of hydrogen.
Use your Periodic Table to help you.
number of protons ..........................................................................................................................
number of neutrons ........................................................................................................................ [2]
(e) Other gases present in Neptune’s atmosphere include ethane and water vapour.
(i) Calculate the relative molecular mass of ethane, $C_2H_6$.
Use your Periodic Table to help you.
relative molecular mass = .......................................................... [2]
(ii) Describe a chemical test for water.
test ....................................................................................................................
result ................................................................................................................. [2]
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The following substances are present in a liquid floor cleaner.
coloured dyes
ethanol
preservatives
sodium carbonate
(a) (i) Balance the chemical equation for the complete combustion of ethanol.
$C_2H_5OH + 3O_2 \rightarrow ....CO_2 + ....H_2O$ [2]
(ii) Draw the structure of an ethanol molecule showing all of the atoms and all of the bonds. [2]
(b) Aqueous sodium carbonate is alkaline.
(i) Which one of the following pH values is alkaline?
Put a circle around the correct answer.
pH 3 pH 6 pH 7 pH 10 [1]
(ii) Aqueous sodium carbonate is colourless.
An excess of aqueous sodium carbonate is added to a solution of dilute sulfuric acid and methyl orange.
Describe the colour change.
from .................................................. to ........................................................ [2]
(iii) The chemical equation for the reaction between sodium carbonate and dilute sulfuric acid is shown.
$Na_2CO_3 + H_2SO_4 \rightarrow Na_2SO_4 + CO_2 + H_2O$
Write the word equation for this reaction.
........................................................................................................................................ [2]
(c) Preservatives stop the growth of bacteria and fungi.
State the name of an acidic gas used to preserve food.
.................................................................................................................................... [1]
(d) The coloured dyes in the liquid floor cleaner can be separated using the apparatus shown.
P ........................................................................
Q ........................................................................
[2]
(i) Complete the boxes to label P and Q. [2]
(ii) State the name of this method of separation.
..................................................................................................................................... [1]
(iii) On the diagram, put an X to show where the mixture of coloured dyes is placed at the start of the experiment. [1]
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The table shows the properties of four substances.
[Table_1]
(a) Complete the table to show the electrical conductivity of solid graphite and solid potassium. [2]
(b) Give one piece of evidence from the table that shows that iodine is a simple covalent substance. [1]
(c) What information in the table shows that zinc chloride is an ionic compound? [2]
(d) Molten zinc chloride can be electrolysed.
Predict the products of this electrolysis at
the positive electrode (anode), ........................................................
the negative electrode (cathode). .................................................... [2]
(e) Aqueous iodine is formed when aqueous chlorine is added to aqueous potassium iodide.
Use ideas about reactivity to explain why this reaction occurs. [1]
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Titanium is extracted from an ore which contains titanium(IV) oxide, TiO$_2$.
(a) (i) Balance the chemical equation for the first step in this extraction.
$\text{TiO}_2 + ......\text{C} + ......\text{Cl}_2 \rightarrow \text{TiCl}_4 + 2\text{CO}$ [2]
(ii) Explain why the conversion of carbon to carbon monoxide is an oxidation reaction.
................................................................................................................................................. [1]
(b) Titanium is a transition element. Sodium is a Group I element.
Describe two differences in the physical properties of titanium and sodium.
1 ............................................................................................................................................
.................................................................................................................................................
2 ............................................................................................................................................
................................................................................................................................................. [2]
(c) The properties and relative reactivity with water of some Group I elements are shown in the table.
[Table_1]
(i) Complete the table
- for the relative reactivity of lithium with water,
- to predict the melting point of potassium. [2]
(ii) Describe the general trend in the density of the Group I elements.
................................................................................................................................................. [1]
(d) Is lithium oxide an acidic oxide or a basic oxide? Explain your answer.
................................................................................................................................................. [1]
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The diagram shows a fractionating column used for the fractional distillation of petroleum.
(a) Describe the fractional distillation of petroleum.
In your answer, include
• where the petroleum enters the fractionating column,
• the relative temperatures in the fractionating column (higher or lower),
• the relative boiling points of the fractions (higher or lower),
• the changes in physical state which occur. ........................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
................................................................................................................................. [4]
(b) Alkenes can be made by cracking the kerosene fraction.
(i) What is meant by the term cracking? ..........................................................................................................................................................
............................................................................................................................................................ [2]
(ii) When butane is cracked, ethene and gas X are produced.
$$C_4H_{10} \rightarrow 2C_2H_4 + X$$
State the name of gas X. .......................................................................................................................................................... [1]
(c) Complete the sentence about the bonding in butane.
All the bonds in butane are single ........................ chemical bonds. [1]
(d) Ethene is used to make poly(ethene).
Which one of the following words describes poly(ethene)?
Put a circle around the correct answer.
gas monomer polymer solvent [1]
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(a) A few drops of liquid bromine were placed at the bottom of a beaker containing cyclohexane. After 3 days, a red-brown colour had spread throughout the beaker.
Explain these observations using the kinetic particle model.
(b) The structure of a compound containing bromine is shown.
(i) Deduce the molecular formula of this compound showing the number of carbon, hydrogen, oxygen and bromine atoms.
(ii) State the name of the functional group.
(c) The relative atomic mass of bromine is 80.
Complete the definition of relative atomic mass using terms from the list.
6, 12, an atom, an element, a molecule, average, carbon, hydrogen, total
Relative atomic mass is the ....................... mass of naturally occurring atoms of ........................ on a scale where ....................... of the $^{12}$C isotope has a mass of exactly ....................... units.
(d) Dilute hydrobromic acid reacts with magnesium ribbon.
(i) Suggest three ways of increasing the rate of this reaction.
1 ...............................................................................................................................
2 ...............................................................................................................................
3 ...............................................................................................................................
(ii) Hydrobromic acid reacts with oxygen. The products are water and bromine.
Balance the chemical equation for this reaction.
.....HBr + O$_2$ → 2H$_2$O + 2Br$_2$
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Ammonia is manufactured by combining nitrogen and hydrogen at high temperature and pressure.
catalyst
nitrogen + hydrogen ⇌ ammonia
(a) (i) What is the meaning of the symbol ⇌?
............................................................................................................................... [1]
(ii) What is the purpose of the catalyst?
............................................................................................................................... [1]
(b) The graph shows the percentage yield of ammonia at different temperatures.
(i) Describe how the percentage yield of ammonia changes with temperature.
............................................................................................................................... [1]
(ii) Deduce the percentage yield of ammonia at 400°C.
............................................................................................................................... [1]
(c) Copper(II) oxide reacts with ammonia.
copper(II) oxide + ammonia → copper + nitrogen + water
When 20g of copper(II) oxide react with an excess of ammonia, 16g of copper are formed.
Calculate the mass of copper formed when 140g of copper(II) oxide react with an excess of ammonia.
..................... g [1]
(d) Ammonia is used in the manufacture of nylon.
Give one use of nylon.
............................................................................................................................... [1]
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