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Effect of Temperature on Rate of Reaction

Materials required 

Burette, burette stand, burner, tripod stand, wire gauze, measuring cylinders, stopwatch, conical flask, 0.1 M sodium thiosulphate, 1.0 M hydrochloric acid, paper with a mark ‘X’ at the center. 

 

The Procedure

Real lab procedure

A. The effect of concentration on the rate of reaction 

  • Add 50 mL 0.1 M sodium thiosulphate to the conical flask.
  • Place the conical flask on the paper that has ‘X’ mark at the center. 
  • Add 1.0 mL of 1.0M HCl to the conical flask. Start the stopwatch immediately when half of the HCl (0.5 mL) is transferred to the conical flask and swirl it. 
  • Go on observing from the top of the flask and stop the stopwatch  when the cross marks just becomes invisible.  
  • Note down the time. 
  • Repeat the experiment by adding 2 mL, 4 mL, 8 mL and 16 mL of 1.0 M hydrochloric acid solution to fresh sodium thiosulphate solution every time and record the time required for the disappearance of the mark ‘X’ in each case separately. 
  • Plot a graph for the volume of HCl added (which determines concentration of HCl) and the time taken for the mark to become invisible, the variation in time is plotted on x-axis and the variation in volume is plotted in y-axis.

B. The effect of temperature on the rate of reaction 

  • Add 50 mL sodium thiosulphate to the conical flask. 
  • Place the conical flask on the paper that has ‘X’ mark at the center. 
  • Measure the room temperature(T) of the solution by using a thermometer. 
  • Add 5 mL of 1.0 M hydrochloric acid solution with swirling.
  • Start the stopwatch immediately when half the amount (i.e., 2.5 mL) of hydrochloric acid has been transferred. 
  • Record the time at which the mark ‘X’ becomes invisible. 
  • Add 50 mL of fresh sodium thiosulphate to the clean conical flask. 
  • Heat the solution such that the temperature is increased by 100C than the previous solution.(T+10° C). 
  • Place the conical flask on the paper that has mark ‘X’ at the center using a holder. 
  • Add 5 mL of 1.0 M hydrochloric acid solution with swirling.
  • Start the stopwatch immediately when half the amount (i.e., 2.5 mL) of hydrochloric acid has been transferred. 
  • Record the time at which the mark ‘X’ becomes invisible. 
  • Repeat the experiment by increasing the temperature by 37°C, 47°C, 57°C, 67° C from the room temperature. 
  • Plot a graph between temperature and the time taken for the mark to become invisible. For plotting the graph, the variation in time is plotted on x-axis and the variation in temperature is plotted on y-axis.                                                                     

Simulator procedure

A. The effect of concentration on the rate of reaction 

  • Set up the UI as shown in figure. 
  • Select the method- Effect of temperature / Effect of concentration. 
  • Click on the bottle cap to open the HCl solution. 
  • Drag and drop the HCl towards the burette to fill it. 

a) The effect of concentration on the rate of reaction 

  • Click on the bottle cap to open the Na2S2O3  solution. 
  • Drag and drop the bottle containing Na2S2O3 towards the 50ml measuring cylinder. 
  • Drag and drop the measuring cylinder containing 50ml of Na2S2O3  towards the conical flask to transfer the solution into it.
  • Drag and drop the conical flask containing Na2S2O3 towards the burette to place it under it. 
  • Click on the stopcock of the burette to open the burette containing HCl. 
  • Wait until 0.5ml of HCl is transferred from the burette into the conical flask. 
  • Click on  the stopcock of the burette  to close it. 
  • Click on the stopwatch to start the timer. 
  • Drag and drop the conical flask outside the stand to shake it. 
  • Click on the stopcock of the burette to open it and pour the rest of 0.5ml of HCl into the conical flask. 
  • Drag and drop the conical flask towards the tile that contains an ‘X’ mark. 
  • Wait for the time taken for the ‘X’ mark to completely disappear when we observe through the solution. 
  • Click the stopwatch to stop it and note the time. 
  • The input table for the graph will be shown in the controls.
  • Click on the next button. Note: Clean the conical flask and repeat the steps for next conc. of HCl. 
  • Plot the graph based on the table and study the trend.
  • Click on the inference button to study the observation. 
  • Note: The rate of a reaction decreases with the passage of time as the concentration of reactants decreases. 
  • Click on the reset button to redo the experiment or to go to the next method. 

b) The effect of temperature on the rate of reaction 

  • Fill the burette with HCl solution.  

For normal room temperature - T 

  • Click on the bottle cap to open the Na2S2O3  solution. 
  • Drag and drop the bottle containing Na2S2O3 towards the 50ml measuring cylinder. 
  • Drag and drop the measuring cylinder containing 50ml of Na2S2O3 towards the conical flask to transfer the solution into it. 
  • Drag and drop the thermometer towards the conical flask to measure the temperature. 
  • Click on the thermometer to remove it.
  • Note: Show initial room temperature (30 °C). 
  • Drag and drop the conical flask towards the burette containing HCl.
  • Click on the stopcock to pour 2.5ml of the solution to the flask containing Na2S2O3  solution. 
  • Click on the stopwatch to start the timer after 2.5ml is poured to the conical flask. 
  • Drag and drop the conical flask to the canvas to shake it well.  
  • Click on the stopcock to pour rest 2.5ml of the 5mL solution to the flask containing Na2S2O3  solution. 
  • Drag and drop the conical flask towards the tile that contains an ‘X’ mark. 
  • Wait for the time taken for the ‘X’ mark to completely disappear when we observe through the solution. 
  • Click the stopwatch to stop it and note the time. 
  • The input table for the graph will be shown and updated along with the procedure. 
  • Click on the next button. Note: Clean the conical flask and repeat the steps for next temperature. 
  • Repeat the steps for next temperatures.

For other temperatures, 

  • Click on the bottle cap to open the Na2S2O3  solution. 
  • Drag and drop the bottle containing Na2S2O3 towards the 50ml measuring cylinder. 
  • Drag and drop the measuring cylinder containing 50ml of Na2S2O3  towards the conical flask to transfer the solution into it. 
  • Drag and drop the thermometer towards the conical flask to measure the temperature. 
  • Drag and drop the conical flask towards the tripod stand. 
  • Click on the burner to turn it on. 
  • Note: Show that it is heating it up to t + 10°C. 
  • Click on the burner to turn it off. 
  • Click on the thermometer to remove.
  • Drag and drop the conical flask towards the burette containing HCl. 
  • Click on the stopcock of the burette  to pour 2.5ml of the solution to the flask containing Na2S2O3  solution. 
  • Click on the stopwatch to start the timer after 2.5ml is poured to the conical flask. 
  • Drag and drop the conical flask to the canvas to shake it well.  
  • Click on the stopcock of the burette to pour rest 2.5ml of the 5mL solution to the flask containing Na2S2O3  solution. 
  • Drag and drop the conical flask towards the tile that contains an ‘X’ mark. 
  • Wait for the time taken for the ‘X’ mark to completely disappear when we observe through the solution. 
  • Click the stopwatch to stop it and note the time. 
  • The input table for the graph will be shown in the controls. 
  • Click on the next button. Note: Clean the conical flask and repeat the steps for next temperature. 
  • Click on the Plot the graph button to plot graph based on the values on the table and study the trend.
  • Click on the inference button to study the observation. 
  • Note: The Rate of reaction increases with increase in temperature. 
  • Click on the reset button to redo the experiment or to go to the next method. 

Note: Click on the ‘HELP’ button to see the instructions. 

 

Observations 

A. The effect of concentration on the rate of reaction 

Sl. No Vol of HCl added(mL)  Time required for the mark ‘X’ to disappear (s) 
 1 1  
2 2  
3 4  
4 8  
5 16  

 

 

B. The effect of temperature on the rate of reaction 

Sl. No Temperature of the reaction mixture(°C)  Time required for the mark ‘X’ to disappear (s) 
1 T  
2                         T+ 10  
   3                         T+ 20  
   4                         T+ 30  
   5                         T+ 40  

                                                                       Note: T is the room temperature 

 

Plotting the Graph 

Plot two graphs, one for the volume of HCl added (which determines concentration of HCl) and the time taken for the mark to become invisible and the other between temperature and the time taken for the mark to become invisible. For plotting the graph, the variation in time is plotted on x-axis and the variation in volume or temperature is plotted on y-axis. 

 

Conclusions 

  • The rate of a reaction decreases with the passage of time as the concentration of reactants decreases. 
  •  Rate of a reaction increases with increase in temperature. 

 

Precautions 

  • The apparatus must be thoroughly clean. 
  • Measure the volumes of sodium thiosulphate solution and HCl very accurately. 
  • Use the same paper with the cross mark for all observations. 
  • When half of the HCl has been added to sodium thiosulphate solution, start the stopwatch immediately. 
  • View the cross mark through the reaction mixture from top to bottom and from same height for all the observations.