Definition The Process Examples

Slides:

Advertisements

Similar presentations

Conductivity A Conductor is a substance that allows electricity to pass through it. An Insulator is a substance that will not allow electricity to pass.

Advertisements

Electrolysis of solutions solutions can be electrolysed; gases are usually produced gases produced can be collected in test tubes; identified later by.

contents Electrolysis of molten compounds Electrolysis of solutions

Electrolysis Of Brine Noadswood Science, 2012.

Let’s read! Pages 82 to 89. Objectives To know how to carry out electrolysis experiments. To work out what happens to ions at each electrode. To be able.

Electrolysis Electrolysis breaks down ionic substances into simpler substances by using electricity!

Author: J R Reid Electrochemical Cells – Voltage (Electric potential) The half cells Standard electrode potentials Calculating voltages Examples.

Higher Unit 3 Electrolysis. After today’s lesson you should be able to:  Use ‘Q = I x t’ to calculate - the value of faraday - the mass of product at.

1 Negative Ions - Bromine Negative ions are attracted to the positive electrode. The positive electrode is called the anode. Negative ions are called anions.

Chemistry C Atomic Structure

Chemistry 1011 Slot 51 Chemistry 1011 TOPIC Electrochemistry TEXT REFERENCE Masterton and Hurley Chapter 18.

Electrolysis of ionic compounds Putting electrical energy in to force the nonspontaneous change.

By Alex, Matt, Kit and Katie

KNOCKHARDY PUBLISHING

Oxidation and reduction reactions occur in many chemical systems. Examples include the rusting of iron, the action of bleach on stains, and the reactions.

Electrolysis (I) LQ: What happens at the electrodes?

DAILY QUESTIONS Circle the oxidized element, underline the reduced element. 2Sr +O 2  2SrO Fe +2 +O 2  FeO Define what happens to elements that are oxidized.

ELECTROLYSIS. Compare and contrast voltaic (galvanic) and electrolytic cells Explain the operation of an electrolytic cell at the visual, particulate.

Do now! Can you read through the blast furnace equations?

Electrolysis. –A redox reaction that is made to occur by passing a direct electric current through an electrolyte Electrolyte –is a liquid that conducts.

ELECTROLYSIS Decomposition using an electric current.

Explain the process of electrolysis and its uses

Chemical Bonding. Ionic Bonds Ionic bonds are made between metal and non-metal atoms Electrons are transferred from the metal atom to the non-metal atom.

Chemical Bonds & Reactions Chemical Bond A force of attraction that holds two atoms together involves the sharing or transfer of valence electrons.

Electrolysis Process by which an electric current is passed through a substance to cause a chemical change. The chemical change is one in which the substance.

Chapter 8 Ionic Compounds Define chemical bond Describe the formation of postive & negative ions.

Splitting up ionic compounds (F) Molten compounds

Electrolysis Decide on the answer(s) then click and a rectangle will surround the correct answer(s).

Positively charged ions and negatively charged ions are attracted to each other and this attraction is the basis of ionic bonding.

The purpose of electrolysis is to split up ionic compounds using electricity to produce useful products. Electrolysis is used a lot in industry and is.

Chemical effect of electric current How things work.

Electrolysis L.O: To be able to describe the uses and predict the products of electrolysis.

Electrolysis Noadswood Science, 2012.

Title: Lesson 6 Electrolytic Cells Learning Objectives: – Describe electrolytic cells – Identify at which electrode oxidation and reduction takes place.

Chapter 16.  the chemical principles, half-equations and overall equations of simple electrolytic cells; comparison of electrolytic cells using molten.

Extracting metals. Methods of extracting metals The Earth's crust contains metals and metal compounds such as gold, iron oxide and aluminium oxide, but.

Electrolytic Cells Section 9.2. Vocabulary Electrolysis: electrical energy used to bring about a non-spontaneous redox reaction Electrolyte: any substance.

J Brewin Deer Park School

Conductors and non-conductors Conductors are materials that conduct electricity. Non-conductors or insulators are materials that do not conduct electricity.

Electrolysis. What is electrolysis? Electrolysis means “breaking up a compound with electricity” From the Greek Electro – electricity Lysis – breaking.

9.2 Electrochemical cells. Two types of electrochemical cells Voltaic cell Spontaneous Chemical  Electrical Uses activity differences between two metals.

ELECTROLYSIS BONDING, STRUCTURE & PROPERTIES. After completing this topic you should be able to : BONDING, STRUCTURE & PROPERTIES ELECTROLYSIS Explain.

BONDING. WHY ATOMS COMBINE -1 All atoms want a full outer shell Some atoms will lose electrons to empty their shells These become positively charged ions.

Oxidation Reduction. Definitions ► Oxidation- an element has lost electrons to another element. ► Reduction- an element gains electrons from another element.

9.5 Electrolytic Cells. Match up the words with their descriptions Test for Oxygen Test for Hydrogen Electrolyte Relights a glowing splint Makes a ‘popping’

AQA GCSE C2.7.  When an ionic substance is melted or dissolved in water (to make a solution) the ions become free to move.  Electrolysis can then be.

What are the two equations used to calculate rates? Rate of reaction = amount of reactant used Time And Rate of reaction = C2 REVISION – Section C2.4.1.

Electrolytic Cells. An electrolytic cell is an electrochemical cell that undergoes a redox reaction when electrical energy is applied. It is most often.

Some metals react with;

Electrolytic Cells.

Starter Under what conditions do ionic compounds conduct electricity?

Chemistry AS – Redox reactions

C3.4 – Electrolysis and cells

Impure copper is purified by electrolysis using the apparatus shown.

Make sure you revise the following:

A complete circuit is required for electric current to flow

An electrolytic cell uses electricity to do a chemical reaction.

C6.2 Changes at the electrodes

C4 – Chemical changes Key Concepts.

1.5c Learning Outcomes carry out an experiment to demonstrate the displacement reactions of metals (Zn with Cu2+, Mg with Cu2+) explain what happens at.

Title: Electrolysis Complete the activities listed below

Presentation transcript:

Definition The Process Examples Electrolysis Definition The Process Examples

What is Electrolysis? All oxidation and reduction reaction involve the transfer of electrons. Some of these reactions are spontaneous – they happen ‘naturally’ without any help from external forces. For example: Sodium oxidises to sodium ions in water (Na → Na+ + e-) Fluorine gas reduces to fluoride ions in water ( F2 + 2e- → 2F-) But sometimes we want to get the reverse reaction to occur i.e. we want to make sodium and fluorine. This does not happen spontaneously so we have to force the electrons to travel in the opposite direction. To force electrons to move we use electricity. This is a process called electrolysis

The Process Electrolysis is a very useful way of making elements from ionic compounds. The process involves placing two electrodes into a dissolved or molten ionic compound. A current is passed through the liquid and the ions are attracted to the electrodes: Cathode – this electrode attracts cations. It is negatively charged. It gives electrons to the cations, therefore reducing them Anode – this electrode attracts anions. It is positively charged. It takes electrons from the anions, therefore oxidising them As the ions get to each electrode the anions have their electrons removed and the cations have electrons added. The ions end up losing their charges and are converted back to atoms

Examples of Electrolysis I Electrolysis of water: Because water contains ions it can be electrolysed. It breaks up into Hydrogen and Oxygen The diagram to the right shows a Hoffman voltameter – an apparatus where to electrodes (at the bottom) are used to generate hydrogen and oxygen gas. The two graduated tubes can be used to measure the volume of gas being produced. What are the volume ratios of hydrogen and oxygen?

Examples of Electrolysis II The Extraction of Aluminium Alumina (aluminium oxide) is poured into pot which contains a carbon cathode base Carbon anodes are placed in and about 20000 amps of current is passed through the alumina. The result is CO2 (from the production of O2 at the carbon anode) and molten aluminium which can be poured off From: www.genisim.qc.ca/website/ansys91.htm See: http://www.comalco.com/freedom.aspx?pid=260

Exam Practice - 2008 Can’t see the exam paper below? Have a go at Questions: Six Can’t see the exam paper below? Go to the NCEA website and search for 90311

Exam Practice - 2007 Can’t see the exam paper below? Have a go at Questions: Seven Eight Can’t see the exam paper below? Go to the NCEA website and search for 90311

Exam Practice - 2006 Can’t see the exam paper below? Have a go at Questions: Four Can’t see the exam paper below? Go to the NCEA website and search for 90311

Exam Practice - 2005 Can’t see the exam paper below? Have a go at Questions: Three Six Can’t see the exam paper below? Go to the NCEA website and search for 90311