The two unknown solids are weighed to a mass of 0.15g each. The unknown solids are dropped carefully into the corresponding Erlenmeyer flask wit 50mL of distilled water. The solid in the water must be dissolved and afterwards add 10 drops of Bromecresol green to indicate the change of color when the solution has been titrated. The flask should start with a blue tint. HCl is carefully dropped into the Erlenmeyer flasks with the primed pipette until the solution turn to a green tint.
Table of Contents/Labs Lab # | Title | Page | | Informal Lab Report Procedures & Grading Rubric | 2-4 | 1 | How Many Drops Of Water Can Fit On A Penny? | 5-6 | 2 | Is The Potassium Chloride Mixture Homogeneous or Heterogeneous? | 7 | 3 | What Are The Densities Of Pre- And Post-1982 Pennies? | 8 | 4 | Which Type Of Glassware Is Most Accurate? | 9 | 5 | What Is The Relative Abundance Of Pre- And Post-1982 Pennies In A Sample of 1982 Pennies?
3. How will the concentration of sucrose in water affect the amount of water that diffuses into or out of the potato cells and thereby change the mass of the potato cells? Hypotheses: 1. If the solution inside the dialysis tubing is hypertonic to the water in the beaker, then the glucose will diffuse out of the bag, and the water will diffuse into the bag, however the starch will remain in the bag. This will occur because the water and glucose are small enough to diffuse out of the pores in the dialysis bag, but the starch molecules are too large to fit through 2.
* 5ml of distilled water was poured down the sides of the beaker, swirled and poured into the funnel. * The filter paper containing the precipitate was allowed to dry and then weighed. 1.7g/1.4g * The weight of the filter paper was subtracted (1.1g/0.7g) to give the actual yield of calcium carbonate (0.6g/0.7g). Observations: * When CaCl2 and Na2CO3 were mixed, a white precipitate was noted immediately. * Residual precipitate was observed on the beaker when filtering.
Turn on the hot plate to a medium heat. Wait until all the liquid has evaporated from the substance and then record the color of the dried substance. 6) Repeat steps 1-5 using each of the three other substances. NOTE: Make sure to wipe down all the materials before they are reused. Compounds | Solubility in Water | Solubility in Alcohol | Color if Soluble in H₂O | Conductivity(Scale 1-4) | Color When Dry | Melting Point (°F) | Sucrose | Yes | No | Transparent | Medium (2) | Brown | 366.8 | Sodium Chloride | Yes | No | Transparent | High (3) | Crystallized, Clear | 1474 | Sodium Carbonate | Yes | No | Mostly Transparent | High (3) | White | 1564 | Salicylic Acid | No | Yes | N/A | High (3) | White | 318.2
Lab 5: Osmosis Purpose The purpose of this lab is to familiarize you with osmosis and, specifically, what happens to cells when they are exposed to solutions of differing tonicities. Hypothesis Since the 1% sugar solution is being placed into the same type of environment (1% sugar solution), the result should be no change in weight of the simulated cell. However, when the 1% sugar solution is placed into a 50% sugar solution environment, the cell will shrink in size because of the hypertonic tonicity; the water will rush out of the cell to create equilibrium through osmosis, resulting in the shrinkage of the cell. On the contrary, when a 50% and a 20% sugar solution are placed onto an environment of 1% sugar solution, respectively, the cells will bloat up and explode (possibly not in this experiment depending on the strength of our tubing) due to the hypotonic tonicity; the water from the 1% sugar solution will rush into the cell to create an equal amount of solute-to-solution ratio inside, and outside, of the cell. Materials & Methods Materials: · Scale · 4 6” Dialysis Tubing · 4 Transfer Pipets · Sugar · Scissors · Rubber Bands · 4 Same-Sized Coffee Cups · 250ml Graduated Cylinder · Tape Measure · Sauce Pan · 3 600ml Containers · Plastic Covering · Spoon Methods: 1.)
Gently stir the resulting mixture for 30-60 seconds. * Step 4 –Place a suitable filter (cloth, filter paper or a fine sieve) over an empty glass, and secure it with the rubber band. Pour the mixture into the filter. If the mixture is too thick, stir in more of the extraction solution. Leave to filter for about 10 minutes.
Then by writing a balanced chemical equation and using the titration formula, Nb+Ma+Va=Na+MbVb , the molarity is able to be determined. Procedure: 1) Using the graduated cylinder add 10.0 mL of water into the Erlenmeyer flask. 2) Add 5.0 mL of HCl into the flask using another graduated cylinder because acid goes into water when mixing them. 3) Add three drops of phenolphthalein indicator into the flask. 4) Swirl the flask in circular movements to mix the substances.
12. Repeat steps four through ten two more times. Variables: Controlled – * Water Temperature * Drop size * Height of drop * Side of penny * Person who drops water on the pipette * That the penny is dry * Amount of mixture for each solution Independent – * Aqueous solution * Penny Dependent – * Number of drops for each solution Data Collection & Processing: Number of drops of an aqueous solution on a penny Substances | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 | Average | Class Averages | Tap water | 46 | 43 | 46 | 35 | 43 | 43 (42.6) | 34 (33.5) | Salt water | 46 | 30 (Phil shook table) | 39 | 21 | 25 | 32 (32.2) | 27 (27.18) | Soapy water | 17 | 31 | 25 | 19 | 23 | 23 | 16 (16.45) | Conclusion & Evaluation: The hypothesis is supported by the data recorded. The hypothesis states that if water is polar and cohesive then the purer the water the more drops that will collect on the penny. If the student averages are compared for tap water, salt water, and soapy water then tap water
They were glucose, water, lemon juice, Coca Cola, egg batter, lemon-lime soda, diet lemon-lime soda, Kraft Italian dressing, skim milk and butter. The positive control was the glucose and the negative control was the water. Twenty drops of each sample of substance was added to the test tubes (in all there were 10 test tubes). After the solutions were added in their own test tube, 20 drops of Benedict’s reagent was added. Each individual test tube was placed in boiling water and removed after 5 minutes to test if