STAGE 2 CHEMISTRY

ASSESSMENT TYPE 1: Investigations Folio

Practical Investigation: Preparation of an Ester.

Purpose

This task allows you to demonstrate your ability to prepare an organic compound. This supervised assessment provides you with the opportunity to demonstrate your:

ability to manipulate apparatus using safe and ethical investigation procedures

ability to evaluate procedures with suggestions for improvements

ability to use appropriate chemistry terms, conventions, formulae and equations

skills in individual and collaborative work.

Description of assessment

Using the method provided on the attached sheet, this preparation will assess:

the well-organised, safe and effective manipulation of apparatus for reflux, distillation, liquid-liquid extraction procedures

the quality of the product prepared

the chemical reasoning behind the procedures followed

the reasoning behind the suggested improvements

the correct use of chemical terms, conventions, formulae, and equations

skills in individual and collaborative work.

Assessment conditions

The preparation and the practical report will be completed, in lesson time, under supervision.

The preparation will be conducted in pairs, but individual reports will be written.

Page 1 of 6 Stage 2 Chemistry annotated task Ref: A185246 (revised January 2013)

© SACE Board of South Australia 2013

Preparation conducted collaboratively but individual report written.

Stage 2 Chemistry Practical (S): PREPARATION OF AN ESTER

The preparation and the practical report will be completed under supervision.Aim: To prepare an ester and to purify it.

Materials:

Quickfit apparatus measuring cylinders (10

mL, 25 mL) glacial acetic acid (pure

ethanoic acid) 3-methyl-1-butanol concentrated sulfuric acid

boiling chips 20 mL sodium carbonate

solution fused calcium chloride small conical flask &

stopper 200 C thermometer

Procedure:

Part A: Preparation of Ester

1. Measure 15 mL of the alcohol provided and 10 mL glacial (pure) acetic acid into the 50 mL pear-shaped Quickfit flask.

2. Slowly add about 1 mL concentrated sulfuric acid and a few boiling chips.

3. Assemble the glassware for reflux.

4. Reflux the mixture for 30 minutes.

Part B: Isolation of Pure Ester

5. Pour the cooled mixture into a separating funnel which contains about 20 mL water. Shake and allow the layers to separate.

6. Collect the organic layer and wash it a second time with water.

7. Collect the organic layer and wash it with about 20 mL sodium carbonate solution.

8. Collect the organic layer and wash it with about 20 mL distilled water.

9. Collect the organic layer in a small conical flask containing fused calcium chloride. Stopper, swirl and allow to stand for 15 minutes.

10. Decant the organic liquid into a clean, dry 50 mL pear-shaped flask and add boiling chips.

11. Assemble the glassware for distillation.

12. Distil the ester, recording the boiling range of the fraction collected. The boiling points of relevant chemicals are shown in the table below.

Boiling Point (C)

ethanoic acid 118

3-methyl-1-butanol 131

commercial grade ester 120 - 145

pure ester 142

sulfuric acid (approx) 142

13. Note the appearance and odour of the ester.

Page 2 of 6 Stage 2 Chemistry annotated task Ref: A185246 (revised January 2013)

© SACE Board of South Australia 2013

Isolation procedures described without explanation to allow students to demonstrate evidence of skills of analysis and evaluation in the separate report against all levels of the performance standards.

Only the outline of the procedure is provided. Student needs to select, and use effectively, appropriate apparatus for the preparation and isolation procedures to demonstrate evidence of careful, effective, well-organised and safe investigation procedures. Allows students to demonstrate evidence of constructive collaborative work skills.

Practical is split into three parts (A, B and Report) to allow for completion, under supervision, in up to three separate periods.

Part C: PRACTICAL REPORT

When you have completed your practical you are to write a practical report using the two headings below and covering the material indicated under the two headings.

Note: The use of dot points is recommended.

Results:

Record the boiling range of your distillate.

Present your product for the teacher to inspect.

Discussion:

In your discussion you should:

Write an equation for the reaction used and state the systematic name of the ester formed.

Explain the purpose of:

the reflux

all isolation procedures, using equations where appropriate.

Explain why this method of preparation usually results in a poor yield of ester.

Suggest how the procedure could be modified to:

improve the yield of ester

improve the purity of the ester.

Describe hazards associated with this preparation and the precautions taken to ensure safety.

Page 3 of 6 Stage 2 Chemistry annotated task Ref: A185246 (revised January 2013)

© SACE Board of South Australia 2013

Open-ended instructions in the Discussion allow students to demonstrate breadth of evidence of learning against all levels of the performance standards.

Additional comments

This assessment would contribute to the assessment of a student’s ability to use appropriate chemical terms, conventions, formulae and equations.

Observation could be used to assess the student’s ability to:- manipulate apparatus to implement safe and ethical work procedures.- demonstrate skills in individual and collaborative work.

Quality of product contributes to evidence of careful and effective manipulation of apparatus and implementation

Learning Requirements Assessment Design Criteria Capabilities

1. Demonstrate and apply knowledge and understanding of chemical concepts and interrelationships

2. Formulate questions, manipulate apparatus, record observations in practical chemical activities, and design and undertake chemistry investigations

3. Demonstrate an understanding of how knowledge of chemistry can be used to make informed conclusions or decisions, taking into account social and environmental contexts

4. Develop possible solutions to a variety of problems in chemistry in new or familiar contexts

5. Critically analyse and evaluate chemical information and procedures from different sources

6. Communicate in a variety of forms using appropriate chemical terms and conventions.

Investigation

The specific features are as follows:

I1 Design of chemistry investigations plans.

I2 Selection and acknowledgment of information about chemistry and issues in chemistry from different sources.

I3 Manipulation of apparatus and technological tools to implement safe and ethical investigation procedures.

I4 The obtaining, recording, and display of findings of investigations using appropriate conventions and formats.

Analysis and Evaluation

The specific features are as follows:

AE1 Analysis of data and concepts and their connections, to formulate conclusions and make relevant predictions.

AE2 Evaluation of procedures, with suggestions for improvement.

Application

The specific features are as follows:

A1 Application of chemistry concepts and evidence from investigations to solve problems in new and familiar contexts.

A2 Use of appropriate chemistry terms, conventions, formulae, and equations.

A3 Demonstration of skills in individual and collaborative work.

Knowledge and Understanding

The specific features are as follows:

KU1 Demonstration of knowledge and understanding of chemistry concepts.

KU2 Use of knowledge of chemistry to understand and explain social or environmental issues.

KU3 Communication of knowledge and understanding of chemistry in different forms.

Communication

Citizenship

Personal Development

Work

Learning

Page 4 of 6 Stage 2 Chemistry annotated task Ref: A185246 (revised January 2013)

© SACE Board of South Australia 2013

Performance Standards for Stage 2 Chemistry

Investigation Analysis and Evaluation Application Knowledge and Understanding

A Designs logical, coherent, and detailed plans for chemistry investigations.

Critically and logically selects and consistently and appropriately acknowledges information about chemistry and issues in chemistry from a range of sources.

Manipulates apparatus and technological tools carefully and highly effectively to implement well-organised safe and ethical investigation procedures.

Obtains, records, and displays findings of investigations using appropriate conventions and formats accurately and highly effectively.

Critically and systematically analyses data and their connections with concepts, to formulate logical and perceptive conclusions and make relevant predictions.

Critically and logically evaluates procedures and suggests a range of appropriate improvements.

Applies chemistry concepts and evidence from investigations to suggest solutions to complex problems in new and familiar contexts.

Uses appropriate chemical terms, conventions, formulae, and equations highly effectively.

Demonstrates initiative in applying constructive and focused individual and collaborative work skills.

Consistently demonstrates a deep and broad knowledge and understanding of a range of chemistry concepts.

Uses knowledge of chemistry perceptively and logically to understand and explain social or environmental issues.

Uses a variety of formats to communicate knowledge and understanding of chemistry coherently and highly effectively.

B Designs well-considered and clear plans for chemistry investigations.

Logically selects and appropriately acknowledges information about chemistry and issues in chemistry from different sources.

Manipulates apparatus and technological tools carefully and mostly effectively to implement organised safe and ethical investigation procedures.

Obtains, records, and displays findings of investigations using appropriate conventions and formats mostly accurately and effectively.

Clearly and logically analyses data and their connections with concepts, to formulate consistent conclusions and make mostly relevant predictions.

Logically evaluates procedures and suggests some appropriate improvements.

Applies chemistry concepts and evidence from investigations to suggest solutions to problems in new and familiar contexts.

Uses appropriate chemical terms, conventions, formulae, and equations effectively.

Applies mostly constructive and focused individual and collaborative work skills.

Demonstrates some depth and breadth of knowledge and understanding of a range of chemistry concepts.

Uses knowledge of chemistry logically to understand and explain social or environmental issues.

Uses a variety of formats to communicate knowledge and understanding of chemistry coherently and effectively.

C Designs considered and generally clear plans for chemistry investigations.

Selects with some focus, and mostly appropriately acknowledges, information about chemistry and issues in chemistry from different sources.

Manipulates apparatus and technological tools generally carefully and effectively to implement safe and ethical investigation procedures.

Obtains, records, and displays findings of investigations using generally appropriate conventions and formats with some errors but generally accurately and effectively.

Analyses data and their connections with concepts, to formulate generally appropriate conclusions and make simple predictions, with some relevance.

Evaluates some procedures in chemistry and suggests some improvements that are generally appropriate.

Applies chemistry concepts and evidence from investigations to suggest some solutions to basic problems in new or familiar contexts.

Uses generally appropriate chemical terms, conventions, formulae, and equations with some general effectiveness.

Applies generally constructive individual and collaborative work skills.

Demonstrates knowledge and understanding of a general range of chemistry concepts.

Uses knowledge of chemistry with some logic to understand and explain one or more social or environmental issues.

Uses different formats to communicate knowledge and understanding of chemistry with some general effectiveness.

Page 5 of 6 Stage 2 Chemistry annotated task Ref: A185246 (revised January 2013)

© SACE Board of South Australia 2013

Investigation Analysis and Evaluation Application Knowledge and Understanding

D Prepares the outline of one or more chemistry investigations.

Selects and may partly acknowledge one or more sources of information about chemistry or an issue in chemistry.

Uses apparatus and technological tools with inconsistent care and effectiveness and attempts to implement safe and ethical investigation procedures.

Obtains, records, and displays findings of investigations using conventions and formats inconsistently, with occasional accuracy and effectiveness.

Describes basic connections between some data and concepts, and attempts to formulate a conclusion and make a simple prediction that may be relevant.

For some procedures, identifies improvements that may be made.

Applies some evidence to describe some basic problems and identify one or more simple solutions, in familiar contexts.

Attempts to use some chemical terms, conventions, formulae, and equations that may be appropriate.

Attempts individual work inconsistently, and contributes superficially to aspects of collaborative work.

Demonstrates some basic knowledge and partial understanding of chemistry concepts.

Identifies and explains some chemistry information that is relevant to one or more social or environmental issues.

Communicates basic information to others using one or more formats.

E Identifies a simple procedure for a chemistry investigation.

Identifies a source of information about chemistry or an issue in chemistry.

Attempts to use apparatus and technological tools with limited effectiveness or attention to safe or ethical investigation procedures.

Attempts to record and display some descriptive information about an investigation, with limited accuracy or effectiveness.

Attempts to connect data with concepts, formulate a conclusion, and make a prediction.

Acknowledges the need for improvements in one or more procedures.

Identifies a basic problem and attempts to identify a solution in a familiar context.

Identifies some chemical terms or formulae.

Shows emerging skills in individual and collaborative work.

Demonstrates some limited recognition and awareness of chemistry concepts.

Shows an emerging understanding that some chemistry information is relevant to social or environmental issues.

Attempts to communicate information about chemistry.

Page 6 of 6 Stage 2 Chemistry annotated task Ref: A185246 (revised January 2013)

© SACE Board of South Australia 2013