Experiment # 1 Title: Mixtures and their separation Ai

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Experiment # 1 Title: Mixtures and their separation Aim: To separate the dyes of screened methyl orange indicator by paper chromatography

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Experiment # 1

Title: Mixtures and their separation

Aim: To separate the dyes of screened methyl orange indicator by paper chromatography.

Apparatus: Beaker, screened methyl orange, water, filter paper

Procedure: Measure the depth of the beaker. Cut a filter paper into a rectangular strip to this measurement. Make the line with a pencil 1.5 cm across from the bottom. Place a drop of screened methyl orange indicator on the line. Suspend the filter paper in the beaker with water (depth of water should not exceed 1 cm). Allow the water to move up the filter paper to an appropriate level. Remove the filter paper and allow it to dry. Record all the measurements and observations. NB Attach chromatogram to lab book.

Discussion: What is paper chromatography; list uses of chromatography, what is the purpose of the water, give reason for the separation, why one component moved faster/slower than the other, list one similarity/difference between the separated components.

Precautions/limitations/sources of error:

Conclusion:

EXP. 1: Paper Chromatography ORR

Observations

water soaking up the paper [1 mark]
original colour of dyes [1 mark]
blue colour rising first [1 mark]
yellow dots moving slower [1 mark]

Recording

Date 1, title 1, aim 1, apparatus 1, procedure 2 [6 marks]
chromatography paper or drawing of it: starting line,

finishing line, labelling of dyes [3 mark]

3. Conclusion stated and accurate [2 marks]

Total 15 marks

EXP. 1: Paper chromatography A/I

Discussion of results: [10 marks]

reasons for separation, definition of chromatography,
uses of chromatography, purpose of solvent
reason for components moving faster/slower
similarity/difference between separated components

Experiment #2

Title: Reactions of acids

Aim: To investigate the strength of acids.

Apparatus: 2 mols/dm³ sulphuric acid. 2 mols/dm³ ethanoic acid, powdered zinc, powdered copper, magnesium ribbon, copper(II) oxide, calcium carbonate, test tubes.

Procedure: Place a small amount of one substance in a test tube. Add a small amount of one acid. Observe the reaction. Repeat with other reagents. Repeat with the other acid. Tabulate the results.

Discussion: What is an acid, what is a salt, what is a normal salt, what is an acid salt, what is a strong/weak acid, which acid is strong/weak? Which metal did not react with the acid and why?

Treatment of results:

Write balanced molecular equations for each substance with dilute sulphuric acid.
Write one ionic equation of acids with: (a) a metal (b) an oxide (c) the carbonate
State how you would test for the gas given off from a reaction of an acids with (a) metals (b) carbonates

Limations/precautions/sources of error:

Conclusion:

SBA # 2 Skill: MM

Title: Reactions of acids

Aim: To investigate the strength of acids

Criteria:

1. Handled reagents without spilling 2

2. Always use clean test tubes from rack 1

3. Spatula used to place small quantity of solids in test tubes 1

4. Stoppers replaced immediately after use 1

5. Bottles replaced to proper place after use 1

6. Labels on bottles read before use 1

7. Avoid direct contact between bottles and test tube 2

8. Using only small quantities of reagents 1

Experiment #3

Planning and Designing

Title:

Problem Statement: Plan and design an experiment to determine if the change in melting point of a substance depends on the quantity of impurity present.

Experiment # 3

Marking Scheme P/D

Hypothesis clearly stated and testable 2

Aim stated and linked to hypothesis 1

Apparatus/Materials appropriate ones listed 2

Procedure (appropriate tense/sequence/logical) 3

Diagram of apparatus given 1

Controlled/manipulated/responding variables stated 3

Data to be collected displayed 2

Discussion/Expected results (2); “If” statement (1) 3

One possible source of error/Limitation/Assumption stated 1

TOTAL 18

Experiment #4

Title: Volumetric analysis

Aim: To determine the concentration of hydrochloric acid using 0.1mol/dm³ sodium hydroxide.

Apparatus: 0.1mol/dm³ Sodium hydroxide solution, dilute hydrochloric acid, conical flask, 50cm³ burette, 25cm³ pipette, phenolphthalein indicator.

Procedure: Wash burette with distilled water and then with diluted hydrochloric acid. Fill the burette with the acid. Zero the burette. Pipette 25cm³ of alkali into a conical flask. Add 1- 2 drops of the indicator. Titrate the acid against the alkali until the first colour change. Repeat the procedure until the volume used differs by no more than +/- 0.1cm³. Tabulate the results.

Discussion: What is a neutralisation reaction? Define titration, acid salt, normal salt, use of indicato r, colour change at end point etc.

Treatment of results:

Calculate the average volume of acid used.
Write a balanced molecular and ionic equation
Calculate the number of moles in the volume of alkali used.
Determine the number of moles in the average volume of acid used.
Calculate the molar concentration of the acid.

Precautions:

Sources of error:

Conclusion:

SBA # 4 Skill: AI

Title: Volumetric Analysis

Aim: To determine the concentration of hydrochloric acid

Criteria:

Discussion 5

1. Correct average volume 2

2. Balanced molecular/ ionic equations 2

3. Number of moles of alkali 2

4. Number of moles of acid determined 2

5. Concentration of acid correct 2

SBA # 4

Volumetric Analysis Skill: MM

Aim: To determine the concentration of hydrochloric acid

Criteria:

1. Pipette tip kept below liquid while filling 2

2. Pipette held by stem and not bulb during transportation/handling 2

3. Pipette read at eye level 2

4. Pipette tip touch liquid surface to remove the final drop 2

5. No air bubbles in burette tip after filling 2

6. Fingers correctly positioned around tap while operating burette 2

7. Burette read at eye level 2

TOTAL 14

Experiment # 5

Title: Volumetric Analysis

Aim: To determine the concentration of NaOH using 0.1mol/dm³ H₂SO₄

Apparatus: retort stand, burette, pipette, conical flask, beaker, NaOH, 0.1mol/dm³ H₂SO₄, Phenolphthalein indicator.

Procedure: Rinse burette with the alkali and fill to the zero mark. Pipette 25cm³ of acid into a conical flask. Add 1-2 drops of indicator to the acid in the conical flask. Allow the alkali to run from the burette until the end point is reached. Record the burette reading. Repeat the titration unit readings differ by no more than plus or minus 0.1cm³. Tabulate the results.

Treatment of results:

1. Calculate the average volume of alkali used.

2. Calculate the number of moles of acid in the 25 cm³ volume used.

3. Write equations (molecular/ionic) for the reaction of sulphuric acid with sodium hydroxide.

4. Using the mole ratio from balanced equation, find the number of moles of NaOH in average volume of the solution used.

5. Use the answer in above to find the concentration of the NaOH in mol/dm³ and g/dm³

Precautions/Sources of errors:

Conclusion:

SBA # 5

Volumetric Analysis Skill: MM

Aim: To determine the concentration of sodium hydroxide solution using sulphuric acid.

Criteria:

1. Pipette tip kept below liquid while filling 2

2. Pipette held by stem and not bulb 2

3. Pipette read at eye level 2

4. Pipette tip touched liquid or glass wall to remove the final drop 2

5. No air bubbles in burette tip 2

6. Fingers correctly positioned around tap 2

7. Burette read at eye level 2

TOTAL 14

SBA # 5 Skill: AI

Title: Volumetric analysis

Aim: To determine the concentration of sodium hydroxide.

Criteria:

1. Average volume of acid correct 1

2. Number of moles in average volume of acid correct 2

3. Equation (molecular and ionic) 2

4. Number of moles of alkali used 1

5. Molar concentration correct 2

6. Mass concentration correct 2

TOTAL 10

Experiment #6

Title: Redox Titration

Aim: To determine the concentration of a solution of potassium permanganate using acidified iron (II) solution.

Apparatus: burette, pipette, conical flask, measuring cylinder, potassium manganate (VII) solution, acidified iron (II) [ (NH₄)Fe(SO₄)₂.6H₂O] solution containing 35 g/dm^-3.

Procedure: Fill the burette with potassium permanganate solution. Pipette 25cm³ of acidified iron (II) solution into a conical flask. Titrate iron (II) solution against the potassium manganate (VII) until the first faint permanent pink colour appears. Tabulate the results. Repeat until values differ by no more than +/- 0.1cm³.

Treatment of results;

5Fe²⁺+ MnO₄^- + 8H⁺ Mn²⁺ + 5Fe³⁺ + 4H₂O

1. Calculate the average volume of manganate (VII) used.

2. Calculate the number of moles of iron (II) in the volume used.

3. Calculate the number of moles of permanganate that reacted using mole ratio

4. Calculate the molar and mass concentration of the potassium manganate (VII) used.

5. Identify the reagents is the oxidizing and reducing agent?

6. Explain why no indicator was required for this titration.

Limitations/precautions/sources of error:

Conclusion

SBA #6 Skill A/I

Title: Redox Titration

Aim: To determine the concentration of a solution of potassium manganate (VII) using iron (II) solution.

Criteria:

1. Correct volume of permanganate used calculated 2

2. Correct number of moles of Fe²⁺ calculated 2

3. Correct number of moles of permanganate reacted calculated 2

4. Molar concentration calculated correctly 2

5. Mass concentration correct 2

6. Oxidizing and reducing agent correctly identified 2

7. Explanation for no indicator given and correct 2

TOTAL 14

SBA # 6

REDOX TITRATION Skill: MM

Aim: To determine the concentration of a solution of potassium manganate (V11) using Iron (11) solution.

Criteria:

1. Pipette tip kept below liquid while filling 2

2. Pipette held by stem and not bulb 2

3. Pipette read at eye level 2

4. Pipette tip touch liquid to remove the final drop 2

4. No air bubbles in burette tip 2

5. Fingers correctly positioned around tap while operating burette 2

6. Burette read at eye level 2

TOTAL 14

Experiment # 7

Title: Energetics

Aim: To measure the enthalpy of neutralisation of a reaction.

Apparatus: 1mol/dm³ sodium hydroxide solution, 1mol/dm³ hydrochloric acid solution, Styrofoam cup, beaker, measuring cylinder, thermometer.

Method: Run 50cm³ of aqueous NaOH from a burette into a Styrofoam cup. Record the steady temperature. Run 50cm³ of HCl into a beaker. Record the steady temperature. Add acid solution all at once to the alkali. Stir and record the highest temperature reached.

Discussion: What is chemical energetics, what is enthalpy, enthalpy of neutralisation, what is an exothermic reaction? What is an energy profile diagram?

Treatment of results:

Write a balanced ionic equation for the reaction

What was the number of moles of acid used?

What was the number of moles of alkali used?

What was the number of moles of water formed?

What was the energy change for the reaction?

What was the value of the enthalpy of neutralization?

Draw an energy profile diagram for this reaction?

Precautions/ sources of error

Conclusion:

SBA # 7 Skill: AI

Title: Energetics

Aim: To determine the heat change in substances.

Marking Criteria:

Correct ionic equation given 2

Number of moles of acid/alkali/water formed calculated (1 each) 3

Enthalpy for experiment correctly calculated 2

Enthalpy of neutralization correctly calculated 1

Correct labeled energy profile diagram 2

TOTAL 10

SBA # 7 Skill: MM

Aim:

Marking Criteria:

Measuring cylinder placed on a flat and horizontal surface 1

Measuring cylinder read at eye level 1

Measuring cylinder read at the bottom of the meniscus 1

Liquid stirred for heat distribution 1

Bulb of thermometer immersed long enough for equilibrium 1

Bulb completely immersed in liquid while reading 1

Thermometer correctly read at eye level 1

Thermometer read while bulb immersed 1

Thermometer handed and stored properly 2

Experiment #8

Title: Concentration and rates

Aim: To investigate the effects of concentration on reaction rates.

Apparatus: 0.1mol/dm³ sulphuric acid, 25g/dm³ sodium thiosulphate pentahydrate solution, stopwatch, beakers.

Procedure: Mark a cross X on a blank paper. Measure and add 40cm³ of the thiosulphate to the beaker. Add 40cm³ of the acid and immediately start the stopwatch. Looking from above time how long it will take to completely obscure the cross. Rinse the beaker and repeat using the same volume of acid but decreasing the volume of thiosulphate by 5cm³. Add 5cm³ of water and repeat four more time, each time decreasing the volume of thiosulphate by 5cm³. The total volume must always be 80cm³. Tabulate the results.

Experiment Number	Volume of acid/cm³	Volume of thiosulphate/cm³	Volume of water/cm³	Time (t)/s	1t(s-1)
1	40	40	0
2	40	35	5
3	40	30	10
4	40	25	15
5	40	20	20
6	40	15	25

Treatment of results:

1. Plot a graph of volume of thiosulphate against time. Comment on the shape of the graph.

2. Plot a second graph of 1/t against volume of thiosulphate. Assuming that 1/t is a measure of the reaction rate, how does the reaction rate depend on the concentration of the thiosulphate?

3. Write a balanced molecular and ionic equation for the reaction.

4. Calculate the molar concentration of the thiosulphate solution.

5. Why did the “X” marked on the paper disappeared after a while?

6. Which variables(s) were controlled, manipulated and responded?

Limitations/precaution/sources of error:

Conclusion:

SBA # 8 Skill: ORR

Title: Rates of reaction

Aim: To investigate the effects of concentration on reaction rate

Criteria:

1. Work area kept tidy and clean 1

2. Correct tense used 1

3. Standard English used 2

4. Clear presentation of results in a table 1

5. Title of table self-explanatory 1

6. Columns in table have proper heading 1 (G1) (G2)

7. Title of graphs accurate, capitalized and underlined 4 2 2

8. Correct selection of axis 2 1 1

9. Axis labeled and with appropriate units 2 1 1

10. Accurate curve of best fit 1 1 -

11. Graph occupies 50-75% of the paper 2 1 1

12. Scale given and correct 2 1 1

13. Points accurately plotted 4 2 2

Experiment # 9

Planning and designing

Problem statement: A class was told that magnesium is more reactive than zinc. Formulate a hypothesis concerning the relative reactivity of alloys of magnesium and zinc. Plan and design an experiment to test your hypothesis.

Experiment #10

Title: Qualitative analysis

Aim: To identify cations and anions in samples of salt.

Apparatus: Solution A ,B, C, D ,E and F, dilute nitric acid ,dilute HCl, Aqueous solutions of: Lead nitrate, silver nitrate ,ammonia ,sodium hydroxide ,potassium iodide ,barium chloride ,splint ,red litmus paper, dilute sulphuric acid and nitric acid

TEST	OBSERVATIONS	INFERENCES
1.To a solution of A add aqueous NH₃ drop by drop
2.Add aqueous NaOH to a fresh sample of solution A drop by drop
3.Add in excess NaOH to solution A from test 2 above		Ionic equation required.
4.To a sample of B add aqueous NaOH drop by drop
5. To sample B add aqueous NH₃ drop by drop
6.Add in excess aqueous NH₃ to sample B in test 5 above		Ionic equation required.
7. To a sample of C add aqueous NaOH drop by drop
8. Add aqueous NH₃drop by drop to a sample of C
9. Add aqueous NH₃ in excess to sample C in test 8 above		Ionic equation required
10.To a sample of D add aqueous NH₃ drop by drop
11.To a fresh sample of D add aqueous NaOH drop by drop.
12.Add aqueous NaOH in excess and heat .Test gas with damp red litmus paper
13.To a sample of E add aqueous NaOH drop by drop; then in excess
14.To a fresh sample of E add aqueous KI
15.To a fresh sample of E add aqueous NH₃ in excess		Ionic equation required.
16.To a sample of F add Ba²⁺ followed by dilute HCl /HNO₃ .Heat if necessary.
17.To a dry sample of F add distilled water followed by aqueous barium nitrate. Heat the substance formed.
18. To a sample of D aqueous silver nitrate followed by aqueous ammonia.
19.Repeat procedure 18 on sample G
20.Add aqueous lead nitrate followed by dil. nitric acid to a fresh sample of G		Ionic equation required.

Experipent # 11

Title: Saturated and unsaturated hydrocarbons

Aim: To distinguish between a saturated and unsaturated hydrocarbon

Apparatus: cyclohaxane, cyclohexene, acidified potassium manganate (VII) solution, bromine solution, test tubes.

Procedure: Place 2 cm³ of aqueous bromine and acidified potassium manganate (VII) into each of two test tubes. Label the test tubes A and B. Using a dropper, place a few drops of the alkane into each test tube. Shake and record your observations. Repeat for the alkene.

Observations: Colour of the solutions before and after each addition.

TEST TUBE		REAGENT	Observable changes	COLOUR OF REAGENT
A	CYCLOHEXANE	Potassium manganate VII
B	CYCLOHEXENE	Potassium manganate VII
C	CYCLOHEXENE	Aqueous bromine
D	CYCLOHEXANE	Aqueous bromine

Discussion: What is a saturated hydrocarbon, what an unsaturated solution, why was there a colour change with some solution and not with others, which hydrocarbon is a saturated hydrocarbon and which is an unsaturated hydrocarbon.

Conclusion:

Experiment #12 ORR

Aim: To distinguish between an alkane and an alkene

Criteria:

1. Results/observations placed in a table 1

2. Heading correct for the table 2

3. Correct colour changes with acidified potassium manganate (VII) 4

4. Correct colour changes with aqueous bromine 4

TOTAL 14

INVESTAGATIVE WORK (1)

Different brands of vinegar on a supermarket shelf are labeled to contain 5% acid. Some consumers are not convinced that this is so. Plan and design an experiment to determine if different brands contain the same percentage of acid.

PROPOSAL

Observation/Problem/Research question stated

Hypothesis clearly stated and testable 2

Aim related to hypothesis 1

Material and apparatus appropriate 1

Method suitable (1); manipulating or responding variable stated (1) 2

Control variables stated 1

Expected results reasonable (1); linked with method 2

Assumptions/Precautions/Limitations (any one stated) 1

TOTAL 10

IMPLEMENTATION LAB

(Analysis and Interpretation)

The maximum marks available for the Implementation is 20 marks

The format for this part is shown below.

Method –linked to proposal; change of tense 1 mark

Results 4 marks

Correct formula and equations 2
accurate(2);acceptable(1)
Accuracy of data 2
Accurate(2);Acceptable(1)

Discussion 5 marks

Explanation 2
Points thoroughly developed(1)
Partial(1)
Interpretation 2
Fully supported by data(2);partially(1)
Trends stated 1

Limitation 3 marks

Sources of error identified 1
Precautions stated 1
Limitation stated 1

Reflection 5 marks

Relevance between experiment and real life 1
(self, society and environment)
Impact of knowledge gained from experiment on self 1
Justification of any changes made during experiment 1
Communication of information; scientific language, grammar

and clarity all the time(2);some of the time(1) 2

Conclusion Stated (1); related to aim (1) 2 marks

TOTAL 20 marks

Guideline:

1. Cal # of mol in diluted volume used in titration (25cm³)?

2. Cal. # of mol in total dil. volume (250 cm³)? [Same as the undiluted volume, original volume].

3. Cal mass in the original vol (25 cm³) [ # of mol at 2 * molar mass]

4. Det. % by mass of Ethanoic acid (mass at 3 / mass of original sample{25 cm³}) * 100 [ nb use density to calculate the mass.

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Experiment # 1 Title: Mixtures and their separation Aim: To separate the dyes of screened methyl orange indicator by paper chromatography

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Experiment # 1 Title: Mixtures and their separation Aim: To separate the dyes of screened methyl orange indicator by paper chromatography

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