First I made a water bath by filling the 100 mL beaker with cool tap water. I then placed crushed ice in the 100 mL beaker so the water level was just below the top of the beaker. I sprinkled a little salt in the ice water and mixed it well. I then filled the test tube half full with distilled water and set the test tube in the 24 well plate. I inserted the digital thermometer into the test tube and took reading every 30 seconds until the readings remained constant.
HYPOTHESIS: I hypothesize that the more concentrated sugar solutions will cause a greater amount of osmosis to make each solution isotonic. MATERIALS AND METHODS: Materials: Scale or balance, 24” dialysis tubing, 4 transfer pipets, sugar, scissors, rubber bands, 4 coffee sups of same size, 250ml graduated cylinder, ruler, small sauce and & 3 clean containers (600mls or larger), Methods: 1. Four 6-inch pieces of dialysis tubing were cut and soaked in a coffee cup filled with tap water for 2 hours prior to your start time. While waiting, I prepared the three sugar solutions. A) Added 5 grams of sugar to the 250ml graduated cylinder and then added water up to the 250ml mark.
The samples don’t have to have the same mass as long as it’s between 0.3 and 0.4g. Add about 20mL of water and 3 drops of phenolphthalein indicator to each sample and allow the solid to dissolve. Prepare a 50mL buret for use by washing it, rinsing it with tap water, and rinsing it twice with distilled water. Finally rinse it twice with 5mL portions of your sodium hydroxide solution. Mount the buret on the ringstand and fill it above the zero mark with the prepared sodium hydroxide solution.
» 2 Bunsen burners »2 tripods » 2 wire gauzes » 2 × 150 mL beakers » 2 × 250 mL beakers for 70°C and 80°C water baths » 5 Styrofoam cups for unheated water baths » 8 thermometers 0–100°C » 16 test tubes in a rack » 10 mL measuring cylinder » junket tablet » 50 mL milk » Crushed ice » dropper » plastic spoon » marking pen » Distilled water Note: Thermostatically controlled water baths may be used if available. Method 1 Prepare half-filled water baths by mixing different amounts of tap water, boiling water and ice in the styrofoam beakers to give one of each temperature: 10°C, 20°C, 30°C, 40°C and 50°C. Maintain the 70°C and 80°C temperatures by placing water in the beakers on the Bunsen burners and adjusting with cold water as necessary. Alternatively, use thermostatically controlled water baths for the 30°C, 40°C, 50°C, 60°C, 70°C and 80°C experiments. Place thermometers in each water bath to record the actual temperature in each bath.
Carbohydrates- In this experiment We test for starch. We pour drops of Iodine onto the different liquids. If starch is present the liquid is to turn a blue/black color. Lipids- In this experiment we are testing for lipids. We pour a drop or two of water onto one piece of paper bag and another drop of oil onto a different piece of paper bag.
Effect of temperature on rennin Aim: To test the effect of temperature on the activity of the enzyme rennin Equipment: Solution of rennin, 120mL of milk, 6 test tubes, test-tube rack, stopwatch, measuring cylinder, water bath, ice, thermometer Method: 1. Give each test tube a number from 1-6. 2. In each test tube place 20mL of milk. 3.
To the second, add 10% NaOH dropwise until the pH is 14. (To do this, add a couple of drops of NaOH to the tube; stir thoroughly with a stirring rod; then touch the stirring rod to a piece of pH paper to check your pH.) To the third, add 0.5% sodium bicarbonate solution to pH 9, and to the fourth, add 2% HCl to pH 2. Record your observations on the data sheet. Repeat the above tests using 2% casein solution.
Sac #1 placed into beaker #1 with distilled water, sac #2 placed into beaker #2 with 40% glucose solution and so forth. 3. Before analyzing, we had to allow sacs to remain undisturbed in the beaker for 1 hour. 4. After 1 hour we boiled a beaker of water on the hot plate (for Benedict’s and AgNO3 test).
BE READY WITH THE STOPWATCH. Record the time in the data table. Room Temperature Water: Fill beaker with 80mL of water. Use thermometer to record the temperature Drop Alka-Seltzer tablet in water. Measure the time it takes to completely dissolve.
Now to begin, pour 50 mL of the sodium phosphate buffer solution with a pH of 6.84 into the 150 mL beaker. From here on out, the sodium phosphate buffer solution will be referred to as simply the buffer solution. Next, locate the indicator called bromothymol blue (0.04%) and add 20 drops to your 150 mL beaker. The solution should then appear green. Next, obtain a 5 mL serological pipet and thoroughly rinse it with the buffer solution, then discard the buffer solution into the 250 mL beaker.