Unit 3 Chemistry Laboratory Skills I

AS unit Internally assessed

3.1 Unit description

This unit contains practical assessments that cover the content of Units 1 and 2. There is no specific content for this unit.

Students' laboratory skills will be tested in four different ways, so there will be four separate activities a, b, c and d, which make up this assessment unit. Activity a must cover the three areas of physical, organic and inorganic chemistry. However, over activities b, c and d two of these must be covered. The types of practicals that students must complete for activities b, c and d are qualitative observations, quantitative measurements and preparations.

Edexcel will provide a selection of assessed practical sheets for activities b, c and d. Students can either complete just one assessed practical sheet for each activity, or they can complete more than one for each activity and submit the best mark. The total mark for this unit is 40 marks.

Section ¡¥b, c and d¡¦ include practical activities (40 marks) where the teacher uses Edexcel devised practical activity sheets and mark schemes.

Teachers have the option of marking these activities or having them marked by Edexcel.

3.2 Assessment information

Controlled conditions

These activities must all be carried out under controlled conditions. Students will be allowed to write up their practical reports in a separate lesson, but their materials must be collected at the end of the session and handed back at the beginning of the next session. Students are not permitted to work on their practical sheets out of the lesson. Students¡¦ work must be individual and they may not work with other students in groups.

Assessed practical sheets

The practical sheets for activities b, c and d are confidential and must not be shown to students prior to their completion of them. They will be available on a secure Edexcel website for teachers to download in preparation for delivery.

Activities Activity a: General Practical Competence (GPC)

This will confirm that the students have completed a range of practicals over the whole year and developed their laboratory skills. Students must have carried out at least five practicals in class. By completing these practicals students will be able to:

Verification of completion of these practicals is required as well asthe core practical code, or title of an alternative practical, field of chemistry and dates on which the practicals were carried out. There will be no separate mark awarded for these practical activities.

Activity b: Qualitative observation

Students must complete one qualitative observation, from the selection provided by Edexcel. This activity will include a student sheet, teacher and technician notes and a mark scheme. The activity is marked out of 14.

Activity c: Quantitative measurement

Students must complete one quantitative measurement, from the selection provided by Edexcel. This activity will include a student sheet, teacher and technician notes and a mark scheme. The activity is marked out of 14.

Activity d: Preparation

Students must complete one preparation (making a chemical), from the selection provided by Edexcel. This activity will include a student sheet, teacher and technician notes and a mark scheme. The activity is marked out of 12.

3.3 Tasks for activity b

Tasks for activity b ¡X qualitative observation for the AS are as follows. These tasks will change each year. Please see section 3.6 for further details.

Activity code Title Unit

ASB1 Observation exercise on three inorganic compounds ¡X 1

Unit 2, Topic 2.7: The periodic table ¡X groups 2 and 7

ASB2 Observation exercise on three inorganic compounds ¡X 2

Unit 2, Topic 2.7: The periodic table ¡X groups 2 and 7

ASB3 Observation exercise on three organic compounds

Unit 1, Topic 1.7: Introductory organic chemistry

Unit 2, Topic 2.10: Organic chemistry

ASB4 Observation exercise on two organic compounds

Unit 2, Topic 2.10: Organic chemistry

3.4 Tasks for activity c

Tasks for activity c ¡X quantitative measurement for the AS are as follows.

Activity code Title Unit

ASC1 Acid-base titration ¡X finding the molar mass of a solid acid

Unit 1, Topic 1.3: Formulae, equations and amounts of substance

Unit 2, Topic 2.7: The periodic table ¡X groups 2 and 7

ASC2 Finding the enthalpy change for the reaction between an acid and a base

Unit 1, Topic 1.4: Energetics

ASC3 Sodium thiosulfate(V)-iodine titration Unit 2, Topic 2.7: The periodic table ¡X groups 2 and 7

Unit 3 Chemistry Laboratory Skills I

3.5 Tasks for activity d

Tasks for activity d ¡X preparation for the AS are as follows.

Activity code Title Unit

ASD1 Preparation of a double salt Unit 1, Topic 1.3: Formulae, equations and amounts of substance

ASD2 Preparation of a salt Unit 1, Topic 1.3: Formulae, equations and amounts of substance ASD3 Preparation of an organic compound Unit 2, Topic 2.10: Organic chemistry

3.6 Availability of activity sheets

The activity sheets for activities b, c and d will be available to download from the Edexcel website. They are securely stored so a password is required to access them. These activity sheets are confidential and must not be distributed to students prior to them carrying out the task.

The tasks for activity b ¡X qualitative observation will change each year. The tasks listed in section 3.3 (ASB1, ASB2, ASB3 and ASB4) are only valid from September 2008 to August 2009. New tasks will be available for each following year, on the Edexcel website, as secure files. The new files will have different codes (eg ASB5) to make them easily identifiable.