Questions and Answers
What is the reason for giant ionic structures having high melting and boiling points?
How many other atoms is a carbon atom covalently bonded to in diamond?
4
Why is diamond the hardest natural substance?
Due to its very rigid giant covalent structure
What are two uses of diamond?
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How many other atoms is a carbon atom covalently bonded to in graphite?
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What is a use of graphite and why can it be used for that?
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Why is graphite the only non-metal that is a good conductor of electricity?
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Moles of a gas =
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1 mole of gas always occupies...
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How to find the volume of a substance when you know its mass?
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Volume =
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What will be produced at the cathode if the metal ions are more reactive than hydrogen?
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What will be produced at the cathode if the metal ions are less reactive than hydrogen?
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What will be produced at the anode if halide ions are present?
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What will be produced at the anode if no halide ions are present?
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Electrolysis of sulfuric acid: cathode half equation
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Electrolysis of sulfuric acid: anode half equation
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Electrolysis of sodium chloride: cathode half equation
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Electrolysis of sodium chloride: anode half equation
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Electrolysis of copper(II) sulfate: cathode half equation
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Electrolysis of copper(II) sulfate: anode half equation
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What is 1 faraday?
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What does 1 faraday contain?
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Charge =
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What are the 4 steps to find the mass of substance produced when time and current are given?
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What are two ways ethanol can be produced?
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What are two advantages of making ethanol by reacting ethene with steam?
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What are two disadvantages of making ethanol by reacting ethene with steam?
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What are two raw materials for fermentation to make ethanol?
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What are two advantages of making ethanol by fermentation?
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What are four disadvantages of making ethanol by fermentation?
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What is the method to turn ethanol back into ethene?
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How does the dehydration of ethene work?
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Molar enthalpy change =
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What are three uses of Poly(chloroethene)?
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How are polyesters formed?
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How are polyamides formed?
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What is an example of a polyamide?
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What is another way polyamides are formed?
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What is brine?
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What equipment is used to electrolyse brine?
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Cathode half equation for the electrolysis of brine
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Anode half equation for the electrolysis of brine
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What solution is left behind in the electrolysis of brine?
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What is the contact process used to make?
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1st equation in the contact process
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2nd equation in the contact process
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3rd equation in the contact process
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4th equation in the contact process
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What is H2S2O7?
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What are three uses of sulfuric acid?
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Study Notes
Giant Ionic Structures
- Characterized by high melting and boiling points due to strong electrostatic attractions.
- Structure consists of a closely packed lattice formed by the attraction between oppositely charged ions.
- The strength of attraction increases with higher charges on the ions.
Diamond
- Each carbon atom in diamond is covalently bonded to four other carbon atoms, forming a very rigid structure.
- Diamond is the hardest natural substance due to its strong covalent bonding.
Uses of Diamond
- Commonly used in drill tips and cutting tools.
Graphite
- Each carbon atom in graphite is covalently bonded to three other carbon atoms.
- Acts as a lubricant because it has layers that can slide over each other.
- Good electrical conductor due to free electrons.
Gas Volumes and Moles
- Moles of a gas can be calculated using the formula: volume/24.
- At room temperature and pressure, one mole of gas occupies 24 dm³.
Calculating Volume
- Volume can be calculated using the formula: mass/Mr x 24.
- To find volume given mass, find the relative molecular mass (Mr) of each element involved.
Electrolysis
- Hydrogen is produced at the cathode when metal ions are more reactive than hydrogen; less reactive metals produce a solid metal layer.
- At the anode, if halide ions are present, halides are produced; if absent, oxygen is produced.
Electrolysis Half Equations
- Electrolysis of sulfuric acid:
- Cathode: 2H⁺ + 2e⁻ = H₂
- Anode: 4OH⁻ = O₂ + 2H₂O + 4e⁻.
- Electrolysis of sodium chloride:
- Cathode: 2H⁺ + 2e⁻ = H₂
- Anode: 2Cl⁻ = Cl₂ + 2e⁻.
- Electrolysis of copper(II) sulfate:
- Cathode: Cu²⁺ + 2e⁻ = Cu
- Anode: 4OH⁻ = O₂ + 2H₂O + 4e⁻.
Faraday's Laws
- 1 Faraday corresponds to a charge of 96,000 coulombs, equating to 1 mole of electrons.
- Charge can be calculated as: current x time.
Finding Mass from Electrolysis
- Steps to find mass of substance produced: calculate charge, divide charge by 1 Faraday, find moles from half equation, then calculate mass using moles and Mr.
Ethanol Production
- Two methods to produce ethanol: reacting ethene and steam, or fermentation using sugar and yeast.
- Producing ethanol from ethene is fast and pure but has disadvantages such as being non-renewable and requiring expensive equipment.
- Fermentation is cheap and renewable, but ethanol needs distillation and purification, making it slow with high labor costs.
Dehydration Process
- Dehydration of ethanol involves removing water to revert it into ethene.
Molar Enthalpy Change
- Defined as energy change divided by the number of moles.
Uses of Poly(chloroethene)
- Common applications include clothing, pipes, and insulating electrical cables.
Polymer Formation
- Polyesters are formed from reactions between dicarboxylic acids and diols.
- Polyamides are produced from reactions between dicarboxylic acids and diamines or from amino acids (an alternative method).
Brine and Electrolysis
- Brine is a sodium chloride solution; electrolysis equipment used is known as a diaphragm cell.
- Electrolysis of brine produces hydrogen at the cathode (2H⁺ + 2e⁻ = H₂) and chlorine at the anode (2Cl⁻ = Cl₂ + 2e⁻).
- The leftover solution from this process is sodium hydroxide.
Contact Process for Sulfuric Acid
- Used to produce sulfuric acid, following these equations:
- S + O₂ = SO₂ (first step).
- 2SO₂ + O₂ = 2SO₃ (second step).
- SO₃ + H₂SO₄ = H₂S₂O₇ (third step).
- H₂S₂O₇ + H₂O = 2H₂SO₄ (fourth step).
- H₂S₂O₇ is also known as oleum.
Uses of Sulfuric Acid
- Sulfuric acid is widely used in the production of fertilizers (indirectly), detergents, and paints (also indirectly).
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Description
Test your knowledge of giant ionic structures with these flashcards focused on key concepts from Edexcel IGCSE Chemistry Paper 2. Learn about the properties and characteristics that define high melting and boiling points and the structural arrangement of ionic lattices. Perfect for revision and mastery of essential chemistry terms.
