Analysis by MassAnalysis by Mass

Chapter 2Chapter 2

Unit 3Unit 3

Consists of Area of Study 1Consists of Area of Study 1 Chemical analysis Chemical analysis

Area of Study 2Area of Study 2 Organic Chemical PathwaysOrganic Chemical Pathways

Each area of study will take about a termEach area of study will take about a term Though hopefully quickerThough hopefully quicker

There are 3 sacs and 1 exam a semesterThere are 3 sacs and 1 exam a semester

The ExamThe Exam

This is what you are working towards. This is what you are working towards. The chemistry unit 3 exam is on June 10The chemistry unit 3 exam is on June 10 thth

It consists of 15 minutes reading time and 1.5 It consists of 15 minutes reading time and 1.5 hours writing time. hours writing time.

It is made up of 20 multiple choice questions It is made up of 20 multiple choice questions and about 8 short answer questionsand about 8 short answer questions

You get a data booklet and are allowed a You get a data booklet and are allowed a scientific calculator (no graphics)scientific calculator (no graphics)

The S.A.C.sThe S.A.C.s

There are 3 S.A.C.s in unit 3There are 3 S.A.C.s in unit 3 The first one is in Area of Study 1 The first one is in Area of Study 1

This is the extended experimental investigation This is the extended experimental investigation (E.E.I.)(E.E.I.)

This will begin in week 6 (Mar 9) and will take about This will begin in week 6 (Mar 9) and will take about 3 weeks. 3 weeks.

It consists of 3 practical activities, questions to be It consists of 3 practical activities, questions to be answered on each prac, risk assessments to be answered on each prac, risk assessments to be written for each prac, a report to be written on all 3 written for each prac, a report to be written on all 3 pracs. pracs.

The E.E.I. will be on the analysis of the composition The E.E.I. will be on the analysis of the composition of lawn fertiliserof lawn fertiliser

The next two S.A.C.s will be in area of The next two S.A.C.s will be in area of study 2.study 2.

One will be a practical reportOne will be a practical report One will be a response to written One will be a response to written

stimulusstimulus

The S.A.C.sThe S.A.C.s

Significant FiguresSignificant Figures

All your answers to calculations this year must All your answers to calculations this year must be to significant figures. be to significant figures.

Look at page 470 (Appendix 1)Look at page 470 (Appendix 1) A zero that comes before integers in not A zero that comes before integers in not

significant but a zero that comes after an significant but a zero that comes after an integer is.integer is.

Significant figures is where your final value you Significant figures is where your final value you calculate is only as precise as your least calculate is only as precise as your least precise piece of data. precise piece of data. Meaning your answer has to use the lowest amount Meaning your answer has to use the lowest amount

of significant figures that the question contains.of significant figures that the question contains.

So lets review the holiday So lets review the holiday homeworkhomework

What is the difference between qualitiative and What is the difference between qualitiative and quantitative analysis? quantitative analysis?

What are some analysis techniques and why might we What are some analysis techniques and why might we use them?use them?

Look at page 12 worked example and answer question Look at page 12 worked example and answer question 1 on page 12.1 on page 12.

Remember % by mass is:Remember % by mass is:

Do questions 3 and 5 page 12Do questions 3 and 5 page 12

Final mass of sampleInitial mass of sample

x 100

Empirical FormulaEmpirical Formula Simplest whole number ratio of the atoms present in Simplest whole number ratio of the atoms present in

the compoundthe compound

Step 1: Measure the mass (m) of each Step 1: Measure the mass (m) of each

element in the compoundelement in the compound

Step 2: Calculate the amount in mole (n) Step 2: Calculate the amount in mole (n)

of each element in the compoundof each element in the compound

Step 3: Calculate the simplest whole number ratio of moles Step 3: Calculate the simplest whole number ratio of moles

of each element in the compoundof each element in the compound

Step 4: Determine the empirical formula of the compoundStep 4: Determine the empirical formula of the compound

Molecular FormulaMolecular Formula

Gives the actual number of atoms of Gives the actual number of atoms of each element present in a molecule of each element present in a molecule of compoundcompound

One unit can be the empirical formula One unit can be the empirical formula molecular massmolecular mass

==molar mass of compoundmolar mass of compoundmolar mass of one unitmolar mass of one unit

Stoichiometry Stoichiometry

What equations do we know??What equations do we know?? Page 21Page 21 Lets do question 21 together.Lets do question 21 together.

HomeworkHomework

P.12 Q 1, 3, 5P.12 Q 1, 3, 5 P.25 Q 21, 25, 27, 29, 31 P.25 Q 21, 25, 27, 29, 31 P. 26 Q 36, 41, 42, 44 P. 26 Q 36, 41, 42, 44