WORKSHEET: ph and Water 23 Lab Instructor: Lab Day & Time: Student name(s): DATA AND ANALYSIS ph Substance ph Value Substance ph Value Substance ph Value pure water apple juice dish soap sugar water beer coffee orange juice wine antacid soda pop vinegar tea diet soda pop scouring cleanser tomato juice carbonated water Buffers drain cleaner flat soda pop window cleaner ammonia solution bleach solution ph balanced shampoo household cleaner laundry detergent Solution Initial ph ph After Adding Acid ph After Adding Base Tap water Milk Specific Heat TEMPERATURE CHANGES IN THE HOT WATER BATH, o C ( minutes 0 to 5 ) Time 0:00 0:30 1:00 1:30 2:00 2:30 3:00 3:30 4:00 4:30 5:00 Water Ethanol TEMPERATURES IN THE ICE WATER BATH, o C ( minutes 5.5 to 10 ) Time 5:30 6:00 6:30 7:00 7:30 8:00 8:30 9:00 9:30 10:00 Water Ethanol
WORKSHEET: ph and Water 24 Plot your Specific Heat data on the graph below. Connect the points for water with a solid line and those for alcohol with a dashed line. Set the minimum and maximum limits of the temperature scale (y-axis) close to the minimum and maximum values you recorded. Heat of Vaporization Check one blank in each of the three columns. You have collected data for the first two columns. Your response for the third column can be inferred from responses to the first two. Water Fastest Evaporation Most Intense Cooling Sensation Highest Heat of Vaporization Ethanol
WORKSHEET: ph and Water 25 Surface Tension and Capillary Action For each comparison check the tube in which the contents climbed higher: Comparison Tube diameter Tube type Liquid type Climbed highest 1 Large Glass Water Small Glass Water 2 Small Glass Alcohol Small Glass Water 3 Medium Plastic Water Medium Plastic Alcohol QUESTIONS ph 1. Is a solution with a "high" ph acidic or basic? 2. Which is more concentrated in a "low" ph solution, H + or OH -? 3. Are the reactive qualities of drain cleaner due to an excess of H + or an excess of OH -? 4. Which has more hydrogen ions, wine or water? 5. Vinegar is an acetic acid solution. Does its ph agree with this fact (yes or no)? 6. Do soaps and cleaners tend to be acidic or basic? 7. Did the OH - concentration of diet soda and regular soda differ by a magnitude of 10 times or greater (yes or no)? 8. Did the OH - concentration of pure water and sugar water differ by a magnitude of 10 times or greater (yes or no)?
WORKSHEET: ph and Water 26 9. Did the OH - concentration of fresh soda pop and flat soda pop differ by a magnitude of 10 times or greater (yes or no)? 10. From questions 7, 8, & 9, would you conclude that the ph of soda pop is strongly influenced by: 1) sugar, 2) carbonation, 3) both, or 4) neither? 11. Is fruit juice ph caused by: 1) sugar, 2) carbonation, 3) both, or 4) something else? 12. How many times more basic is a solution with a ph of 9 than a solution with a ph of 8 (2, 10, 20, 100, or 200)? 13. How many times more basic is a solution with a ph of 10 than a solution with a ph of 8 (2, 10, 20, 100, or 200)? Buffers 14. Did our experimental results agree with the fact that milk is a ph buffer? 15. Did the milk buffer: 1) acid, 2) base, or 3) both in our experiment? Specific Heat 16. Which heats most rapidly, ethyl alcohol or water? 17. Which cools most rapidly, ethyl alcohol or water? 18. Which has the higher specific heat, ethyl alcohol or water? 19. If your blood and tissue fluid were alcohol instead of water, would you be more likely to get overheated on a hot day, (yes or no)? 20. Assuming organisms function best if their internal temperatures remain relatively constant as outside temperatures change, would a body fluid with high or low specific heat be best? 21. Palm Springs is almost directly inland from Santa Monica. Which of these places has more water nearby and in the air? 22. Which of these places, Palm Springs or Santa Monica, experiences both hotter and colder temperatures? 23. Other factors being equal, should a humid or dry night be cooler?
WORKSHEET: ph and Water 27 Heat of Vaporization 24. Was the substance that caused the most intense cooling sensation also the most efficient evaporative cooler (yes or no)? 25. Would death by "drying up" be more likely for an organism composed of alcohol or one (like us) composed of water? 26. Does water hold other ions (such as sodium or chloride) in solution by adhesion or cohesion? Capillary Action 27. Based on the behavior of water with wax, oil, and most plastics, would you say that these substances are polar or nonpolar? 28. For capillary action to occur, is it necessary for: 1) only the fluid, or 2) both the fluid and the tube to be polar? 29. Do your experimental results suggest that a tree could move water more effectively from its roots to its leaves using smaller or larger diameter vessels? 30. Mosquitoes can walk on water because of adhesion or cohesion? 31. If ice suddenly lost its well-known ability to float, would this make things better or worse for frogs hibernating at the bottom of ponds in the winter?
WORKSHEET: ph and Water 28