Bonding & Substance Properties (AQA GCSE Chemistry)

Exam Questions

2 hours25 questions
1a3 marks

This question is about states of matter.

Table 1 shows the melting and boiling points of some of the elements in Group 7.

Table 1 

Element Melting point in °C Boiling point in °C
Fluorine –220 –188
Chlorine –101 –35
Bromine –7 59

Give the state of each substance at 50 oC

Fluorine: ___________

Chlorine:___________

Bromine:___________ 

1b3 marks

Use the information from Table 1 to complete the sentence:

Going down group 7, the melting points ____________________. 

This is because the size of the molecules ___________________ so the forces between the molecules get ____________________.

1c4 marks

A solution of potassium bromide will react with lead nitrate in the following reaction:

Pb (NO3)2 (aq) + 2KBr (aq) → 2KNO3 (aq) + PbBr2 (s)

What information does the equation tell you about the products made in this reaction?

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2a2 marks

This question is about magnesium.

Magnesium can be shaped easily. 

Tick () two reasons which explain why metals can be shaped.

Reason why:

Tick 

The atoms are all joined by ionic bonds.

 

The atoms can slide over each other.

 

The atoms are small.

 

The atoms are in layers.

 

2b2 marks

Match the following properties of magnesium with the correct explanation. 

metal-properties-match-up-
2c1 mark

What is meant by an alloy?

2d2 marks

Magnesium can be mixed with other elements to form an alloy to make it harder.

The structure of an alloy is shown in Figure 1.

 
 Figure 1
alloy-structure

Complete the sentence to explain why an alloy is harder than a pure metal:

The atoms in an alloy are different ____________________ so the layers are unable to ____________________ over each other when pressure is applied. 

2e1 mark

Why is it incorrect to describe an alloy as a compound?

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3a2 marks

This question is about silicon dioxide. It's structure is shown in Figure 1. 

Figure 1
silicon-dioxide-structure


Which two elements are found in silicon dioxide?

3b5 marks

Silicon dioxide is used in bricks that line furnaces which operate at high temperatures. 

Use the words in the box to complete the sentences which explain why it can be used for this purpose.

high energy strong low small
six ionic giant four



Silicon dioxide has a ____________________ structure. Each silicon atom is joined to ___________________ oxygen atoms by ___________________ covalent bonds. These bonds need lots of ___________________ to break. Silicon dioxide therefore has a ____________________ melting point. 

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4a4 marks

The structures of five substances are represented below:

aqa-gcse-2-1e-tp4a-mixture-of-substances

Give one substance, A, B, C, D or E that:

 Is a metal

 

 Represents the structure of diamond

 

 Is soft and slippery

 

 Is a compound

 

4b1 mark

Which element are substances B and E made from?

4c2 marks

Substance C is methane, CH4.

Tick (✓) two boxes that are correct about this substance.

  It has weak intermolecular forces  
  It cannot conduct electricity  
  It has a high melting point  
  It can conduct electricity  
  It has a low boiling point  

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5a1 mark

This question is about calcium chloride, CaCl2.

What is the total number of atoms in calcium chloride?

5b1 mark

What type of bonding is found in calcium chloride?

Tick (✓) one box.

 Ionic  
 Covalent  
 Metallic  
5c1 mark

How many negative ions are there in the formula for calcium chloride? 

5d3 marks

Suggest three properties of calcium chloride.

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1a5 marks

This question is based on the structure of different substances.

Identify each substance in Figure 1 by writing the letter next to the corresponding sentence. 

Figure 1

aqa-gcse-chem-2-2m-1a

This substance is a liquid: _____

This substance is a gas: _____

This substance is a metal: _____

This substance is diamond: _____

This substance is ionic: _____

1b3 marks

Magnesium is a reactive metal that combusts in air to form magnesium oxide. 

Balance the equation for the reaction below and give the meaning of the state symbols (s) and (g). 

___ Mg (s) + ___O2 (g)   →   ___MgO (s)

1c3 marks

Higher:

The following particle diagrams in Figure 2 are routinely used to represent the three phases of matter: 

Figure 2

aqa-gcse-2-2m-q1c-solid-liquid-gas

State three limitations of these models.

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2a1 mark

A student was investigating a calcium salt labelled Y.

The student found that Y:

  • has a very high melting point
  • does not conduct electricity
  • is water soluble and the solution produced conducts electricity

What type of bonding is present in salt Y?

2b2 marks

Explain why the solid Y does not conduct electricity but its aqueous solution does.

2c1 mark

Figure 1 shows the bonding arrangement of an element. 

Figure 1

2-2-bonding--substance-properties-medium-q2c-copy

What is the element? 

Tick (✔) one box.

Element

 

Chromium

 

Carbon

 

Silicon

 

Graphite

 
2d3 marks

The image in Figure 1 is an allotrope. 

Why does this allotrope conduct electricity? 

2e2 marks

Figure 2 shows the particle diagram of an alloy. 

Figure 2

2-2-bonding--substance-properties-medium-q2e

Explain why this alloy is harder than pure metal Y.

2f1 mark

What kind of substances are alloys?

Tick (✔) one box.

Elements

 

Mixtures

 

Compounds

 

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31 mark

Different substances have characteristic melting and boiling points, depending on the strength of the bonds or forces holding them together.

Which explains why methane has a lower melting point than sodium chloride?

  • Covalent bonds are weaker than ionic bonds

  • Intermolecular forces are weaker than ionic bonds

  • Covalent bonds are stronger than ionic bonds

  • Intermolecular forces are stronger than ionic bonds

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41 mark

Element X has the following properties:

  • melts at 450oC
  • boils at 1091oC
  • Forms an ion with a 2+ charge

Which is most likely to be element X?

  • Sodium

  • Magnesium

  • Carbon

  • Oxygen

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5a2 marks

Marble slabs for kitchen countertops are cut from huge blocks of marble which are extracted from quarries. The extraction process involves cutting the marble blocks with a metal cable connected to a rotary motor. Water is sprayed onto the marble for cooling.

The cable used is made from a steel alloy. 

Suggest two advantages of using an alloy instead of a pure metal for this process.

5b1 mark

For particularly dense marble, or marble which contains grains of other rock types, the cutting cable is encrusted with diamond dust.

Suggest a reason why.

5c4 marks

Diamond has a very high melting points.

Explain why in terms of the bonding arrangement.

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6a3 marks

Explain why diamond has a higher melting and boiling point than carbon dioxide.

6b3 marks

Metals are good conductors of electricity. 

Explain why.

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71 mark

Sodium chloride is often known as 'table salt'. 

Which compound represents sodium chloride?

  Conducts electricity when solid Conducts electricity when molten State at room temperature and pressure Can be bent or shaped
A Yes Yes Solid Yes
B No No Solid No
C No Yes Solid No
D No No Solid Yes

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    81 mark

    Limewater is the common name for calcium hydroxide solution, Ca(OH)2 (aq). It is commonly used as a test for carbon dioxide, whereupon the following reaction occurs:

    Ca(OH)2 (aq) + CO2 (g) → CaCO3 (s) + H2O (l)

    Which of the following statements is not true about the reaction?

    • Calcium hydroxide is dissolved in water

    • One product is a gas

    • The solution will turn cloudy

    • The solution will become increasingly dilute during the reaction

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    9a1 mark

    The hydrogen halides (HF, HCl, HBr and HI) are compounds used to produce acids.

    Figure 1 represents a molecule of hydrogen chloride.

    Figure 1

    aqa-gcse-2-2m-q3a-hydrogen-chloride-bonding

    What do the crosses (X) represent?

    9b1 mark

    What type of bonding is present in this molecule?

    9c3 marks

    Predict whether hydrogen chloride is a solid, liquid or gas at room temperature and pressure. 

    Explain your answer.

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    10a2 marks

    This question is based on the chemistry of polymers.

    Polyvinyl chloride (PVC) is a commonly used polymer.

    State the term used to describe the units from which polymers are made and name the type of bonding between these units.

    10b3 marks

    Figure 1 represents short chains of PVC.

    Figure 1

    2-2-bonding--substance-properties-medium-q4b

    Although hard material is used in water pipes and drains, PVC softens and melts when heated. 

    Use the diagram and your knowledge of structure and bonding to explain why this occurs.

    10c3 marks

    The basic unit of polyvinyl chloride is C2H3Cl.

    The polymer chain consists of many of these base units bonded together.

    In the space provided, draw a section of a chain of PVC showing three units joined together.

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    1a1 mark

    This question is about the bonding in different substances. 

    Table 1 shows some information about substances A - E.

    Table 1

    Substance Melting point in oC Boiling point in oC Does it conduct electricity when solid? Does it conduct electricity when dissolved or molten?
    A -208 -200 No No
    B -220 -180 No No
    C 802 1415 No Yes
    D 115 450 No No
    E 1080 2563 Yes Yes

    Use Table 1 to answer the following questions. 

    Give the state symbol of substance B at -202 oC. 

    1b3 marks

    Substance E can conduct electricity when solid and molten. 

    Explain why.

    1c2 marks

    One of the substances in the table is sodium chloride.

    Identify which substance is sodium chloride.

    Give a reason for your answer.

    1d3 marks

    Explain why substance A has a relatively low boiling point.

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    2a4 marks

    This question is about the bonding and structure of silicon dioxide. 

    Figure 1 shows the structure of part of silicon dioxide. 

    Figure 1

    silicon-dioxide

    Explain why silicon dioxide can be used to line furnaces. 

    2b2 marks

    Explain why silicon dioxide cannot conduct electricity.

    2c2 marks

    Silicon dioxide is a solid at room temperature. 

    Solids can be represented using the particle model in Figure 2. 

    Figure 2

    aqa-gcse-2-2h-tq-2c-particle-model-solid

    Describe two limitations of this model. 
     

    2d2 marks

    Explain how, using particle theory, silicon dioxide would change state from a solid to a liquid.

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    3a2 marks

    This question is about the structure and bonding in ethene. 

    Ethene belongs to the homologous series of alkenes and has the formula  C2H4.

    Complete the dot and cross diagram in Figure 1 to show the bonding of ethene.

    Only show the outer shell electrons.

     
    Figure 1
    aqa-gcse-2-2h-tq-3a-ethane-dot-and-cross-diagram-empty

    3b3 marks

    Table 1 shows information on the boiling points and structures of ethene and two other alkenes.

    Table 1 

    Name Ethene Propene Butene
    Structure ethene aqa-gcse-7-2h-tq3b-propene butene
    Boiling Point in oC -104  -47 -6.3

    Use your knowledge of structure and bonding to describe and explain the trend in boiling point as the number of carbon atoms increases.

    3c3 marks

    Ethene can undergo addition polymerisation to form the polymer poly(ethene).

    Why is poly(ethene) a solid at room temperature?

    3d3 marks

    Complete the structure for poly(ethene) in Figure 2. 


    Figure 2


    aqa-gcse-2-2h-tq-3d-polymerisation-of-ethene

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    4a4 marks

    This question is about sodium chloride and diamond.

    Figure 1 shows the structure of sodium chloride and diamond. 

    Figure 1 

    aqa-gcse-2-2h-tq-4a-sodium-chloride-and-diamond

    Sodium chloride has a melting point of 801oC. 

    Explain why sodium chloride has a high melting point.

    4b2 marks

    Diamond has a melting point of 4500 oC.

    Explain why diamond has a higher melting point than sodium chloride.

    Refer to the structure of diamond in your answer. 

    4c4 marks

    Compare the electrical conductivity of sodium chloride and diamond.

    Explain your answer.

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    5a4 marks

    This question is about metals and alloys.

    Stainless steel is an alloy of iron, chromium and nickel. 

    Iron is a typical metal. 

    Explain why it has a high melting point.

    5b3 marks

    Explain why stainless steel is harder than the iron it is made from.

    5c1 mark

    Early hip replacement joints were made from stainless steel. 

    Apart from being harder, suggest one other property of stainless steel that made them useful as hip replacement joints.

    5d1 mark

    Explain why nickel and chromium are both good thermal conductors.

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