Properties of substances SG Chemistry, Topic 7

Conductivity of elements and compounds Standard Grade Chemistry Topic 7

Learning outcomesSuccess criteria Know which elements can conduct electricity.You can write a rule linking the type of element to whether or not it can conduct electricity. Given the name of an element, you can state whether or not it can conduct electricity. Know which types of compound can conduct electricity. Given the name of a compound, you can state whether it is made up of metal and non-metal elements or only non-metal elements. You can write a rule linking the types of elements which make up a compound to whether or not it can conduct electricity. Given the name of a compound and its state, you can state whether it can conduct electricity or not.

Gold Lead Sodium Silicon Carbon Iodine Hydrogen Bromine Mercury SulphurPotassiumPhosphorus What do the above substances have in common? – Elements Which of them conduct electricity?

Gold Lead Sodium Silicon Carbon Iodine Hydrogen Bromine Mercury SulphurPotassiumPhosphorus What do the above substances have in common? – Elements Which of them conduct electricity? – Metal elements and carbon (graphite) Does it make a difference what state the elements are in? – No

Graphite and diamond

Write a rule which summarises which elements can conduct electricity. – All metal elements can conduct electricity (whether solid or liquid); non-metal elements do not conduct electricity in any state, with the exception of carbon (graphite).

True or false All solid elements conduct electricity. All liquid elements conduct electricity. All metal elements conduct electricity. No non-metal element conducts electricity. Solid oxygen conducts electricity. Liquid oxygen conducts electricity. Solid calcium conducts electricity. Liquid calcium conducts electricity. Solid carbon conducts electricity.

True or false All solid elements conduct electricity. All liquid elements conduct electricity. All metal elements conduct electricity. No non-metal element conducts electricity. Solid oxygen conducts electricity. Liquid oxygen conducts electricity. Solid calcium conducts electricity. Liquid calcium conducts electricity. Solid carbon conducts electricity.

Learning outcomesSuccess criteria Know which elements can conduct electricity.You can write a rule linking the type of element to whether or not it can conduct electricity. Given the name of an element, you can state whether or not it can conduct electricity. Know which types of compound can conduct electricity. Given the name of a compound, you can state whether it is made up of metal and non-metal elements or only non-metal elements. You can write a rule linking the types of elements which make up a compound to whether or not it can conduct electricity. Given the name of a compound and its state, you can state whether it can conduct electricity or not.

Practical – conductivity of compounds If you were to investigate whether a compound can conduct electricity or not, what equipment would you need? – Power pack / battery – Wires – Bulb

COMPOUND

Practical – conductivity of compounds Which compounds would you chose to investigate?

Results Do compounds of metals/non-metals conduct electricity when solid? – No Do compounds of metals/non-metals conduct electricity when liquid? – Yes Do compounds of metals/non-metals conduct electricity when dissolved? – Yes

Results Do compounds of non-metals/non-metals conduct electricity when solid? – No Do compounds of non-metals/non-metals conduct electricity when liquid? – No Do compounds of non-metals/non-metals conduct electricity when dissolved? – No

Do they conduct electricity? Solid sodium chloride (salt) Solid glucose (C 6 H 12 O 6 ) Liquid potassium iodide Solid methane Dissolved lithium nitrate CaO(s) Al(OH) 3 (l) CsCl(aq) H 2 O 2 (l) C 12 H 22 O 11 (aq)

Do they conduct electricity? Solid sodium chloride (salt) Solid glucose (C 6 H 12 O 6 ) Liquid potassium iodide Solid methane Dissolved lithium nitrate CaO(s) Al(OH) 3 (l) CsCl(aq) H 2 O 2 (l) C 12 H 22 O 11 (aq)

Learning outcomesSuccess criteria Know which elements can conduct electricity.You can write a rule linking the type of element to whether or not it can conduct electricity. Given the name of an element, you can state whether or not it can conduct electricity. Know which types of compound can conduct electricity. Given the name of a compound, you can state whether it is made up of metal and non-metal elements or only non-metal elements. You can write a rule linking the types of elements which make up a compound to whether or not it can conduct electricity. Given the name of a compound and its state, you can state whether it can conduct electricity or not.

Ions Standard Grade Chemistry Topic 7

Learning outcomesSuccess criteria Understand what ions are.You can define the term ion. You can describe two ways in which ions can be formed. For elements 1-20, you can: – name their ions – draw symbols for their ions – draw shell diagrams of their ions – write electron arrangements for their ions

Ion migration Standard Grade Chemistry Topic 7

Learning outcomesSuccess criteria Understand what ion migration is.You can explain the results of an ion migration experiment, including: specific colours the direction which these move ions positive / negative attract

Thought experiment

Thought experiment: NaCl(aq) Concentration (mol/l)Current (A)

Thought experiment: C 6 H 12 O 6 (aq) Concentration (mol/l)Current (A)

Why the difference? Types of elements present? Types of particle each is made up of?

Learning outcomesSuccess criteria Understand what ion migration is.You can explain the results of an ion migration experiment, including: specific colours the direction which these move ions positive / negative attract

Electrolysis Standard Grade Chemistry Topic 7

Learning outcomesSuccess criteria Understand what electrolysis is.You can define the term “electrolysis”. You can name the type of energy which changes a chemical during electrolysis. From the name of a compound, you can – name the ion which will move to each electrode – state which ion gains electrons and which ion loses electrons – name the substance that will be produced at each electrode

Learning outcomesSuccess criteria Know what an electrolyte is.You can define the term “electrolyte”. You can identify a substance as a electrolyte or not. Understand why a d.c. supply must be used during electrolysis. You can state what “d.c.” stands for. You can state why a d.c. supply must be used.

Theory of dissolving / melting

Electrolysis Copper Chloride Why must a d.c. power supply be used? What happens to the mass of each electrode?

Chemistry of electrolysis Substance+ve electrode Ion-electron equation -ve electrode Ion-electron equation Aluminium iodide (molten) Zinc bromide (solution) Iron(II) chloride (solution)

Learning outcomesSuccess criteria Understand what electrolysis is.You can define the term “electrolysis”. You can name the type of energy which changes a chemical during electrolysis. From the name of a compound, you can – name the ion which will move to each electrode – state which ion gains electrons and which ion loses electrons – name the substance that will be produced at each electrode

Learning outcomesSuccess criteria Know what an electrolyte is.You can define the term “electrolyte”. You can identify a substance as a electrolyte or not. Understand why a d.c. supply must be used during electrolysis. You can state what “d.c.” stands for. You can state why a d.c. supply must be used.

Why can ionic compounds conduct electricity? Standard Grade Chemistry Topic 7

Learning outcomesSuccess criteria Understand what an electric current is.You can describe what an electric current is in terms of: – charged particles – movement You can state the three examples of situations in which an electric current can flow.

Learning outcomesSuccess criteria Understand how a current can flow in solutions or melts. You can state the name of the charged particles which can flow in solutions/melts. You can state what charge these particles can have. You can state where these charged particles come from.

Conduction and molecules Solid Particles can’t move freely Liquid or solution Particles can move freely Does not conduct – no charged particles

Conduction and ions Solid Particles can’t move freely Liquid or solution Particles can move freely Does not conduct – ions can’t move freely Conducts – ions can move freely

The rule To conduct, charged particles must be able to move freely. –In compounds, the charged particles are ions. –The compound must be a liquid (melt) or dissolved to conduct.

Learning outcomesSuccess criteria Understand how a current flows in wires.You can state the name of the charged particles which can flow in wires. You can state what charge these particles have. You can state where these charged particles come from.

Types of bonding and structure Standard Grade Chemistry Topic 7

Covalent bonding What is a covalent bond? In what types of substance do we get covalent bonds? Examples? What do we know about substances with covalent bonding and their ability to conduct electricity?

Ionic bonding In what types of substance do we get ionic bonds? Examples? What do we know about substances with ionic bonding and their ability to conduct electricity?

Reading, note taking, questions Standard Grade Chemistry textbook, p66-67 Assessment Test 7.1 and 7.2