ib chemistry on kinetics experiments and rate of chemical reaction for ia design

Techniques Used to measure Rate of Reactions

Reaction between CaCO3 with HCI can be measured using THREE different methods

CaCO3 + 2HCI → CaCI2 + CO2 + H2O

Method 1 Method 2 Method 3

Method 1

• Rate of reaction measured as Δ in mass CaCO3 over time

• Apparatus is set up shown below where initial mass and its contents are recorded

Procedure

•CaCO3 + 2HCI → CaCI2 + CO2 + H2O (CaCO3 is limiting, HCI is excess)

•Pour 50ml of 0.5M HCI into conical flask and place it on electronic balance

•Weigh accurately 1.00g of CaCO3 and place it on electronic balance

• Record down the total mass and add CaCO3 into flask and start stopwatch immediately

• Mass of flask is recorded for every 1 min interval shown in table

• Repeat expt using 1.0M HCI

• Rate of reaction using 1.0M HCI is faster > than 0.5M HCI

Results

Research Questions possible

• Effect of Temperature, Surface area of CaCO3, Concentration on rate of reaction





Method 1





Method 2

• Rate of reaction measured as Δ in volume CO2 over time

• Apparatus is set up with burette filled with water and initial volume recorded

Procedure

• CaCO3 + 2HCI → CaCI2 + CO2 + H2O (CaCO3 is limiting, HCI is excess)

• Excess CaCO3 added to 20ml of 0.5M HCI and CO2 released is recorded at 1 min interval



Results







Method 2





Method 3

• Rate of reaction measured as Δ in pressure CO2 over time

• Apparatus is set up where the test tube is link to gas pressure sensor

Procedure

• CaCO3 + 2HCI → CaCI2 + CO2 + H2O (CaCO3 is limiting, HCI is excess)

• Excess CaCO3 added to 10ml of 0.5M HCI and pressure due to CO2 released is recorded

at 1 min interval



Results







Method 3


Reaction between Na2S2O3 with HCI can be measured using TWO different methods

Na2S2O3 + 2HCI → 2NaCI2 + SO2 + H2O + S

Method 1 Method 2

Method 1

• Rate of reaction measured as Δ in mass sulphur or 1/ Time for Disappearance of cross X

• Apparatus is set up shown below

Procedure

• Na2S2O3 + 2HCI → 2NaCI2 + SO2 + H2O + S (Na2S2O3 is limiting, HCI is excess)

•Pour 50ml of 0.2M HCI into conical flask and place it on top of white paper with cross X

• Pour 5.0ml of 0.1M HCI into flask

• X is view vertically from the top and record the time for X to disappear

• Repeat expt with different Na2S2O3 concentration




Method 1 Method 2

Method 1

• As concentration increases ↑ , rate increases ↑

Results


• Effect of Temperature and Concentration on the rate of reaction

• What is the order of reaction with respect to HCI and Na2S2O3 concentration ?




Method 1 Method 2

Method 2

• Rate of reaction measure as Δ light intensity or 1/Time for light intensity to drop due to sulphur formation


Procedure

• Na2S2O3 + 2HCI → 2NaCI2 + SO2 + H2O + S (Na2S2O3 is limiting, HCI is excess)

• Pipette 1ml 0.2M S2O3 of into cuvette

• Place it above a light sensor and measure the light intensity

• Pipette 0.1ml of 1.0M HCI into cuvette and start data collection. Record the initial time

• Record the time for light intensity to drop (due to sulphur formation)

• Repeat expt with different Na2S2O3 concentration




Method 1 Method 2

Method 2


Results

Research Questions possible • Effect of Temperature and Concentration on the rate of reaction

• What is the order with respect to HCI and Na2S2O3 concentration ?


Reaction between H2O2 with I - can be measured using TWO different methods

H2O2 + 2I - + 2H+ → 2H2O + I2

I2 + 2S2032- → S406 2- + 2I -

I2 + starch → Blue black

H2O2 - Oxidising Agent I - - Reducing Agent S203

2- - Reduces I2 to I –

I2 - Once all used up, I2 will react with starch forming blue black

Iodine Clock Reaction

Method 1 Method 2

Method 1

• Rate of reaction measure as Δ in mass I2 or 1/Time for disappearance of X due to blue black formation


• H2O2 + 2KI + 2HCI → 2KCI + 2H2O + I2 (KI is limiting, H2O2 is excess)

• Pipette 5ml 3% H2O2, 5ml of 0.1M HCI, 1ml 1% starch, 1ml of 0.001M S2O3 of into conical flask

• Place it on top of white paper with cross X and pipette 5 ml of 0.1M KI into flask


• Repeat expt with different KI concentration

Procedure



H2O2 + 2I - + 2H+ → 2H2O + I2

I2 + 2S2032- → S406 2- + 2I -






Method 1 Method 2

Method 1

Results




• What is the order or reaction with respect to H2O2 and KI concentration ?



H2O2 + 2I - + 2H+ → 2H2O + I2

I2 + 2S2032- → S406 2- + 2I -






Method 1 Method 2

Method 2

• Rate of reaction measure as Δ in absorbance or 1/Time for absorbance to increase (blue black formation)


• H2O2 + 2KI + 2HCI → 2KCI + 2H2O + I2 (KI is limiting, H2O2 is excess)

• Pipette 0.5ml 3% H2O2, 0.5ml of 0.1M HCI, 0.1ml 1% starch, 0.1ml of 0.001M S2O3 of into cuvette

• Pipette 0.5ml of 0.1M KI in cuvette and record the initial time

• Record the time for when absorbance rises (formation of blue black colouration)

• Repeat expt using 0.5ml of different KI concentration

Procedure



H2O2 + 2I - + 2H+ → 2H2O + I2

I2 + 2S2032- → S406 2- + 2I -






Method 1 Method 2

Results

Research Questions possible • Effect of Temperature and Concentration on the rate of reaction

• What is the order of reaction with respect to H2O2 and KI concentration ?


Method 2


Reaction between S2O82- with I - can be measured using TWO different methods

S2O82- + 2I - → 2SO4

2- + I2

I2 + 2S2032- → S406 2- + 2I -


S2O82- - Oxidising Agent

I - - Reducing Agent S203




Method 1 Method 2

Method 1

Procedure

• Rate of reaction measure as Δ in mass I2 or 1/Time for disappearance of X due to blue black formation


• S2O82- + 2I - → 2SO4

2- + I2 (KI is limiting, S2O82- is excess)

• Pipette 5ml 0.1M KI, 5ml of 0.001M S2O3 ,1ml 1% starch into conical flask

• Place it on top of white paper with cross X and pipette 5 ml of 0.1M S2O82- into flask


• Repeat expt with different KI concentration



S2O82- + 2I - → 2SO4

2- + I2

I2 + 2S2032- → S406 2- + 2I -







Method 1 Method 2

Method 1

Results




• What is the order of reaction with respect to S2O82- and KI concentration ?



S2O82- + 2I - → 2SO4

2- + I2

I2 + 2S2032- → S406 2- + 2I -







Method 1 Method 2

Method 2

Procedure

• Rate of reaction measure as Δ in absorbance or 1/Time for absorbance to increase (blue black formation)


• S2O82- + 2I - → 2SO4

2- + I2 (KI is limiting, S2O82- is excess)

• Pipette 0.5ml 0.1M KI, 0.1ml of 0.001M S2O3 , 0.5ml 1% starch into cuvette

• Place cuvette into a visible spectrophotometer and start data collection

• Pipette 0.5ml of 0.1M S2O82- into cuvette and record the initial time

• Record the time for when absorbance rises (formation of blue black colouration)




S2O82- + 2I - → 2SO4

2- + I2

I2 + 2S2032- → S406 2- + 2I -







Method 1 Method 2

Results




• What is the order of reaction with respect to S2O82- and KI concentration ?

Method 2


Reaction between H2O2 with KI can be measured using TWO different methods

2H2O2 → O2 + 2H2O (KI as catalyst)

Method 1 Method 2

Method 1

• Rate of reaction measured as Δ in volume O2 over time

• Apparatus is set up with burette filled with water and initial volume recorded

Procedure

• 2H2O2 → O2 + 2H2O (H2O2 is limiting, KI is excess)

• Pipette 1ml of 1.0M KI to 20ml of 1.5% H2O2 and O2 released is recorded at 1 min interval

• Expt repeated using 3% H2O2 concentration




Method 1 Method 2

Method 1

Results




• What is the order of reaction with respect to H2O2 concentration ?

• Effect of different catalyst on the rate of reaction.




Method 1 Method 2

Method 2

• Rate of reaction measured as Δ in pressure of O2 over time

• Apparatus is set up with flask link to gas pressure sensor

Procedure

• 2H2O2 → O2 + 2H2O (H2O2 is limiting, KI is excess)

• Pipette 1ml of 1.0M KI to 20ml of 1.5% H2O2 and O2 released is recorded at 1 min interval

• Expt repeated using 3% H2O2 concentration




Method 1 Method 2

Method 2

Results




• What is the order of reaction with respect to H2O2 concentration ?

• Effect of different catalyst on the rate of reaction.


Reaction between Fe3+ + I - can be measured using TWO different methods

Fe 3+ - Oxidising Agent I - - Reducing Agent

Method 1 Method 2

Method 1

• Rate of reaction measure as Δ in absorbance or Increase in absorbance due to iodine


• 2Fe3+ + 2I - → 2Fe2+ + I2 (I -

is limiting, Fe3+ is excess)

• Pipette 1.5ml 0.02M Fe3+into cuvette. Determine the λ max for Fe3+ solution (450nm)

• Set spectrophotometer to Absorbance vs time mode and select λ = 450nm

• Pipette 1.0ml of 0.02M Fe3+, 1.0ml of KI into cuvette and mix them

• Place cuvette into spectrophotometer and measure the absorbance increase due to I2 formation


Procedure

2Fe3+ + 2I - → 2Fe2+ + I2



Method 1 Method 2

Method 1

2Fe3+ + 2I - → 2Fe2+ + I2

Results




• What is the order of reaction with respect to Fe3+ and I - concentration ?




Method 1 Method 2

Method 2

• Rate of reaction measure as Δ in concentration of I2 or Increase in I2 concentration over time


• 2Fe3+ + 2I - → 2Fe2+ + I2 (I - is limiting, Fe3+ is excess)

• Pipette 25ml of 0.02M KI , 25ml of 0.02M Fe3+ into a conical flask. Start the time

• For every 5mins, pipette 10ml of solution mixture into a flask and titrate with S2O32-

(Reaction mixture contains I2 formed which will react with S2O32-) Amt of I2 produced can be determine.

• I2 + 2S2032- → S406

2- + 2I – ( Mole ratio is 1:2)

• Perform titration until volume of S2O32- added remains constant (Conc I2 produced remains constant)

Procedure

2Fe3+ + 2I - → 2Fe2+ + I2




Method 1 Method 2

Method 2

2Fe3+ + 2I - → 2Fe2+ + I2

Results

Calculations

• At time 5mins – Vol of S2032- is 6.0ml – Amt of S203

2- = M x V = 0.2 x 0.006 = 0.0012mol

For a reaction : 2Fe3+ + 2I - → 2Fe2+ + I2

• Concentration of product I2 increases with time

• Rate of reaction decreases with time, as the gradient is less steep with time

• As concentration of reactants decreases, rate of I2 production decreases



Reaction between I2 + CH3COCH3 can be measured using TWO different methods

Method 1 Method 2

Method 1

• Rate of reaction measure as Δ in absorbance or Decrease in absorbance due to iodine


• I2 + CH3COCH3 → CH3COCH2I + H+ + I - (CH3COCH3 is limiting, I2 is excess)

• Rate is monitored by disappearance of I2 yellowish solution over time

• Pipette 2ml of 0.002M I2 into cuvette. Find the λ max for I2 (λ max = 520nm)

• Set colorimeter to Absorbance vs Time mode

• Pipette 0.4ml of I2 solution, 0.4ml of 2M HCI and 1ml water into a cuvette

• Start data collection at λ max = 520nm

• Pipette 0.4ml of 0.2M CH3COCH3 into cuvette and record the drop in absorbance over time

• Repeat expt using of different CH3COCH3 concentration .

Procedure

I2 + CH3COCH3 → CH3COCH2I + H+ + I -



Method 1 Method 2

Method 1


Results


• As concentration CH3COCH3 increases ↑ , decrease in absorbance over time increases ↑ , rate increases ↑


• What is the order of reaction with respect to H+, CH3COCH3 and I2 concentration ?



Method 1 Method 2

Method 2

• Rate of reaction measure as Δ in absorbance or Decrease in concentration of iodine

• I2 + CH3COCH3 → CH3COCH2I + H+ + I - (CH3COCH3 is limiting, I2 is excess)

• Rate is monitored by disappearance of I2 yellowish solution over time

• Pipette 2ml of 0.002M I2 into cuvette. Find the λ max for I2 (λ max = 520nm)

• Set colorimeter to Absorbance vs Concentration mode. (Standard calibration curve)

• Prepare a standard calibration curve for Absorbance vs I2 concentration shown below

Procedure


•Pipette 0.4ml of I2, 0.4ml of 2M HCI and 1ml water into a cuvette. Start data collection at λ max = 520nm

•Pipette 0.4ml of 0.2M CH3COCH3 into cuvette and record the drop in absorbance over time

• Repeat expt using of different CH3COCH3 concentration .



Method 1 Method 2

Method 2


Results


• As concentration CH3COCH3 increases ↑ , decrease in absorbance over time increases ↑ , rate increases ↑

Convert Absorbance I2 to Concentration I2

using standard calibration curve


• What is the order of reaction with respect to H+, CH3COCH3 and I2 concentration ?

ib chemistry on kinetics experiments and rate of chemical reaction for ia design

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hci rate of reaction

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h2o method

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