Rate of Reaction - Formation of Sulfur

Authors Avatar by ashunboi1 (student)

Aim:

To investigate the effect of changes in concentration of sodium thiosulfate on the rate of formation of sulphur.

Independent Variable:

Different concentration of sodium thiosulfate (Na2S2O3)

Dependent Variable:

Rate of formation of sulfur

Controlled Variable:

Equipment: The same equipment such as the conical flask would be used throughout the experiment as this would lessen the possibility of errors.

Swirling: The chemical, sodium thiosulfate reacting with hydrochloric acid, in the conical flask would be swirled only twice.

Volume of chemical: The same amount of hydrochloric acid, 5mL, and a total volume of 50mL of sodium thiosulfate and distilled water is to be used throughout the experiment and trials.

Same Cross: The same paper with the cross in the centre will be used throughout the trials as an indication to when the reaction is complete.

Hypothesis:

As the concentration of sodium thiosulfate decreases, the rate of formation of sulfur decreases.  

Materials:

Methods:

  1. Measure out 50mL of prepared sodium thiosulfate in a 50mL cylinder then place into a 250mL conical flask. The different volumes of thiosulfate used throughout the practical constitute the independent variable.
  2. Add 5mL of dilute hydrochloric acid to the flask at the same time as starting a stop watch. Keeping the same timer for each trial is a controlled variable.
  3. Swirl the flask twice (controlled variable) and place it over a piece of white paper with a thick, black cross marked on it.
  4. Look vertically down onto the cross and record the time taken (in seconds) for the cross to disappear. The time taken for the cross to disappear is the dependent variable.
  5. Place 40mL of prepared sodium thiosulfate solution in a 250mL conical flask and add 10mL of distilled water. Total volume is 50mL.
  6. Repeat steps 2-4 using the same cross (controlled variable).
  7. Place 30mL of prepared sodium thiosulfate solution in a 250mL conical flask and add 20mL of stilled water. Total volume is 50mL.
  8. Repeat steps 2-4 using the same cross.
  9. Place 20mL of prepared sodium thiosulfate solution in a 250mL conical flask and add 30mL of distilled water. Total volume of 50mL.
  10. Repeat steps 2-4 using the same cross.
  11. Place 10mL of prepared sodium thiosulfate solution in a 250mL conical flask and add 40mL of distilled water. Total volume is 50mL.
  12. Repeat steps 2-4 using the same cross.
  13. If time permits, conduct a second trial for each of the 50, 40, 30, 20 and 10mL thiosulfate volumes.
Join now!

Saftey Precautions:

Effect of the different concentration of metal solutions to the amount of time taken

Resolution: Stopwatch 0.01 Measuring Cylinder 1mL

Different concentration of Sodium Thiosulfate Affecting on the Time Taken

for the Reaction to be Complete

Different Concentration of Sodium Thiosulfate Affecting

on the Rate of Formation of Sulfur

Discussion:

By collecting results from the investigation, graphs were able to be created to show the relationship between the affects on the concentration of sodium thiosulfate (Na2S2O3) on the rate ...

This is a preview of the whole essay