Factors Affecting Solubility

Materials

Procedures

  1. Caution: test tubes are fragile and they break easily, so be careful! Especially when you turn on the faucet!
  2. Caution: the hot plate gets really hot, so be careful!
  3. Fill the beaker half-full of water from the sink and place it on top of the hot plate.
  4. Boil the water and pour the water with the tongs into the tub marked hot. (Be careful not to burn your self!)
  5. Place the empty beaker on top of the table NOT on the hot plate.
  6. Turn the hot plate off.
  7. Pour some water from the sink into the tub marked cold and obtain some ice and place them into the tub marked cold.
  8. Place the distilled water bottle, labeled �hot�, into the hot tub of water.
  9. Place the distilled water bottle, labeled �cold�, into the cold tub of water.
  10. Leave the unmarked distilled water bottle, on the table, in �room temperature�.
  11. Place test tubes #1 and #2 in the test tube rack.
  12. Place about 0.2 g of salt crystals in each test tube.
  13. Use �room-temperature� water, unmarked distilled water bottle, to fill each test tube about two-thirds full.
  14. Always pour the water carefully down the side of the test tubes so that little mixing occurs as the water is added.
  15. Stopper test tube #2 and invert it.
  16. If all of the salt does not dissolve, invert it again. Continue inverting until all of the salt is dissolved.
  17. Count the number of inversions and record your observations in Data Table 1.
  18. Rinse and dry each test tube.
  19. Place test tubes #1, #2, and #3 in the test tube rack.
  20. Add 0.2 g of salt crystals to each tube.
  21. Fill test tube #1 about two-thirds full of water from distilled water bottle �cold�.
  22. Stopper the tube and invert it to dissolve all of the salt.
  23. Count the number of inversion and record your observations in Data Table 2.
  24. Repeat steps 19 to 23 with test tube #2; this time, use the water from distilled water bottle �room temperature�.
  25. Repeat steps 19 to 23 with test tube #3; this time, use the water from distilled water bottle �hot�.
  26. Rinse and dry each test tube.
  27. Place test tubes #1 and #2 in the test tube rack.
  28. Add 0.2 g of salt crystals to test tube #1
  29. Add 0.2 g of rock salt crystal to test tube #2.
  30. Fill each test tube about two-thirds full of water from distilled water bottle �room-temperature�.
  31. Stopper both test tubes and invert them to dissolve all of the salt.
  32. Count the number of inversion and record your observations in Data Table 3.
  33. If the number of inversions required to dissolve the crystal is greater than 25, stop and record �>25� for the number of inversions in Data Table 3.
  34. Clean up!

Data

Table 1:
Observations number of inversions required
1 ??? test tube not inverted
2 ??? ???

Table 2:
Observations number of inversions required
1 ice-cold water ??? ???
2 water at room temperature ??? ???
3 hot water ??? ???

Table 3:
Observations number of inversions required
1 salt crystal ??? ???
2 rock salt ??? ???

Analysis

1. What is the effect of inversion on the rate of dissolving? ???
2. What is the effect of temperature on the rate of dissolving? ???
3. What is the effect of surface area on the rate of dissolving? ???



How to do this assignment?

Chemistry in February