UNIT TWO: Environmental Chemistry

 Living things on earth have evolved to use water and the gases of the atmosphere in the chemical reactions that sustain them. Water is used by both plants and animals to to carry out their energy-producing reactions, dissolve their nutrients and transport their wastes. The atmosphere supplies life-giving gases, provides temperature that sustains life, and gives protection from harmful radiation. Appropriate chemical concepts are introduced and students are encouraged to evaluate the environmental impact of human activity on the biosphere. All areas of study in this Unit involve the design and performance of experiments, including the generation, collection and evaluation of experimental data.

 Areas of study

• Water
• The Atmosphere

What do I need to know? 

Refer to the course description that need to be met, as listed below (on this page). This information is provided by the VCAA in the Course guidelines, and gives you a clear indication of what you will be learning in this Unit. For assessment purposes, you should refer to the outcomes link, which gives a formal statement of key knowledge and skills that the student should have acquired by the completion of the Unit. Most of these outcome statements apply across a whole semester of work, and as such are useful for exam preparation.

Practice tests / Revision sheets

At this link you will find practice tests on     Acids and Bases     Stoichiometry     

I have also included some chapters of a year 12 book that I wrote some years ago. Each Chapter also has a number of problems associated with the work that you may wish to consider for extra practice. The solutions to these questions are also available from me upon request.

Ch 2 Chemical reactions and stoichiometry

Ch 3 Acids and Bases

Ch 4 Redox Chemistry

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ASSESSMENT: Units One and Two

The award of satisfactory completion for each Unit is based on a decision that the student has demonstrated achievement of the set of outcomes specified for the Unit. This decision will be based on the teacher’s assessment of the student’s overall performance on assessment tasks designated for the Unit. Such assessment tasks must include:

• an extended experimental investigation requiring between three and five hours practical work OR
• a summary report including annotations on three practical activites AND
• a response to stimulus material in written, oral, visual or multimedia format
• an analysis of first or second-hand data using structured questions (a test)
• a response to stimulus material related to green chemistry in written, oral, visual or multimedia format
• topic tests and a 90 minute end of Unit examination (internally assessed).

 Students will be graded from A⁺ to E and as S or N. The VCAA will only be notified as to whether or not the student has satisfactorily completed the Unit. All students must normally satisfactorily complete both Units 1 and 2 if they wish to proceed to Units 3 and 4 Chemistry.

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Course description

Area of Study 1: Water

Outcome 1: Key knowledge

On completion of this Unit students should be able to formulate and write balanced equations and apply these quantitatively and qualitatively to reactions involving acids and bases, the formation pf precipitates and gases, and oxidants and reductants.

  To achieve this outcome the student should demonstrate knowledge of:

·        the important role of water in maintaining life in the environment

• the unique properties of water; the unusual aspects of these properties compared with those of other molecular substances; the significance of these properties to life; the explanation of these properties in terms of hydrogen bonding
• the dissociation of ionic solutes in water and the high solubility of compounds containing the ions Na⁺, K⁺, NH₄⁺ and NO₃^-; the separation of molecules when polar solutes such as sugar and ethanol dissolve in water, the ionisation of polar molecules such as acids
• maintaining water quality: solubility, precipitation reactions, pH
• desalination, including the principles of distillation

·        distinguishing properties of acids and bases: proton transfer, common reactions of acids and bases, strong and weak acids and bases, polyprotic acids, amhiprotic substances

·        acid-base reactions in the environment; for example, the reaction between and acid and a carbonate (acid rain on marble statues), an acid and a hydrogen carbonate (baking powder, antacid powders), an acid and a metal oxide (industrial removal of oxide coatings) and an acid and a metal hydroxide (the addition of slaked lime to the soil, antacid powders)

·        pH as a measure of the acidity of a solution

·       precipitation reactions; use of general solubility rules to predict precipitates formed;

·       conservation of atoms in precipitation reactions; formulas and ionic equations for precipitation reactions

·        simple stoichiometry, including mass/mass and mass/volume/concentration for reactions in solution

·        electron transfer during corrosion of metals; oxidation-reduction; oxidant-reductant; half-equations (aluminium, zinc, magnesium, copper, iron, lead, tin, silver);

·        a simple galvanic cell as a device that illustrates electron transfer during redox reactions; main features of a galvanic cell, including electrodes (anode and cathode), salt bridge, electrode polarity, direction of electron and ion flow;

·       application of the principles of green chemistry; for example, replacement of halogenated solvents with supercritical carbon dioxide in industrial processes or in plant crop protection

Outcome 1: Key skills

  To achieve this outcome the student should demonstrate the ability to:

·       formulate and write balanced equations

·       determine empirical formulas and molecular formulas given elemental composition and molar mass

·        formulate calculate quantities of products and reactants based on balanced chemical equations

·        use a range of indicators to estimate the pH of a solution       

·       use a pH meter to measure the pH of a solution

·        design and perform quantitative experiments

·        apply illustrate the links between the major ideas associated with redox reactions and galvanic cells

·        establish and observe safe laboratory work practices

·        prepare clear, concise reports of laboratory work

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