Tape
String
Permanent marker
Ice
Stove top
Procedure- 1. Mix 40 grams of NaOH into 1000 ml of water. This 1M solution of NaOH is to be used for the remainder of the procedure in place of NaOH.
2. Label the beakers with the tape and permanent marker. Then, fill the beakers. Label one beaker “room temperature” and fill it with 200 ml of water. Label the second beaker “hot”, then fill it with 200 ml of water and place it on the stove top. Label the third beaker “cold”, then fill it with water and ice up to the 200 ml mark accounting for displacement. Turn on the stove.
3. Open one 5 inch length dialysis tubing.
4. Tightly tie off the bottom of the tubing with some string.
5. Fill tubing with 2 ml of NaOH.
6. Tightly tie off the top of the tubing with string.
7. Repeat steps 2-5 with the second and third 5 inch lengths of dialysis tubing.
8. Test and record the PH and temperature of the beakers using the thermometer and the PH probe. Be sure to cleanse the probe and thermometer with distlled water after each, individual test.
9. Simultaneously place a NaOH filled length of dialysis tubing in each of the water filled bowls. Record time.
10. After 5 minutes record the PH and temperature of the beakers.
11. After 10 minutes record the PH and temperature of the beakers.
12. Clean the lab station.
Analysis- The following formulas were using during my investigation.
#moles of solute = (mass in grams / relative atomic mass)
Ex) #moles of (NaOH) = 40 / (23 + 16 + 1)
#moles of (NaOH) = 40 / 40
#moles of (NaOH) = 1
Molarity = #moles of solute / liters of solution
Ex) Molarity = 1/1
Molarity = 1
Change in PH = PH after 10 min. – initial PH
Ex) Change in PH = 12.11 – 7.78
Change in PH = 4.33
Rate of diffusion = change in PH / time
Ex) Rate = 4.33 / 10
Rate = .433 PH/min.
Difference in rate of diffusion = rate of diffusion – rate of diffusion (2)
Ex) Difference in rate of diffusion = .433 PH/min. - .329 PH/min.
Difference in rate of diffusion = .104 PH/min.
Conclusion- As can be seen from the processed data NaOH diffused into the water at a higher rate when heated. Heated NaOH diffused into water at .433 PH/Minute while cooled NaOH diffused into water at .329 PH/min. The heated NaOH diffused .104 PH/Minute faster than the cooled NaOH. This proves my hypothesis which stated that the higher the temperature the quicker the rate of diffusion because, according to Boyle’s law, the higher a substances temperature the faster the molecules move and thus the NaOH will hit the sides of the dialysis tubing more often and with more force allowing for more molecules to escape from the tubing. The procedure I followed could be improved with the use of an electric thermometer for a more accurate temperature analysis. I am also afraid that a small amount of NaOH may have escaped from the tubing through the rudimentary string tie that was used. This could be improved by heat sealing (melting) the end of the tubing for a near perfect enclosure. Also, using three PH probes would better this investigation because there was a delay between the testing of the three beakers which allows more time for the NaOH to diffuse. However, all shortcomings aside, this investigation was successful in determining how temperature effects the diffusion of NaOH into distilled water.