(d) What evidence suggests that nitrate compounds are soluble in water? (e) Write the chemical formula for each precipitate that formed. Apply and Extend (f) Write a balanced chemical equation for each precipitation reaction that occurred. (g) Why is it necessary to use distilled water to prepare the solutions used in this investigation? (h) "Hard" water contains a high concentration of calcium ions.
Method Part 1 1 Clean the surface of the 0.5cm piece of magnesium with a piece of steel wool 2 Place the magnesium into a test tube 3 Add three drops of detergent to the test tube 4 Add 2 cm of hydrochloric acid to the test tube. Set timer for 5 minutes and record your observations, including the height of the foam produced in a results table 5 Repeat the process for the
5mL of acidified water will be measured, using a graduated cylinder, and will be transferred to the R tube, and will be immediately vigrously mixed with the reactants. Once the solution turns to an orange or red-brown color, a pipet will be used to quickly remove 30 drops of the solution, then transferred to the C tube, and the mixing will resume until the solution is close to room temperature. The solution will be filtered into the P tube, and the solution that is left in the R tube should be washed three times with 1mL of acidified water each time. The water should then be poured into the P tube, leaving the solid in the R tube. Using a test tube holder, heat the R tube over the Bunsen burner, moving the tube in a circular motion until all the water has evaporated.
Add 1 mL of deionized water to the small test tube containing the precipitate and mix it and centrifuge it for 60 seconds. Then, add the supernatant into the boiling test tube and repeat this step one more time with another 1 mL of deionized water. Acquire a pair of metal test tube holders and heat the boiling test tube to evaporate the water for 15 minutes. Let is cool after and weigh it. Then, calculate a percent yield of zinc iodide and write a balanced chemical equation and determine the limiting
Materials and Methods Part 1 For the cation elimination test first 10 drops of potassium, iron (III), zinc (II), copper (II), and cobalt (II) were added to 5 centrifuge tubes and the color was recorded. Then for the metal hydroxide test, 6 M NaOH was added drop wise till a precipitate was formed. Each solution except potassium formed a precipitate, so then 10 additional drops of NaOH were added to the remaining solutions. Tubes were cleaned with distilled water and 6 M HCL. Next was the ammonia test 10 drops of each metal solution were added to new centrifuge tubes and 15 M NH4OH was added until the solution changed color or a precipitate was formed.
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.
The purpose of washing the test tubes thoroughly is so the chemicals don’t cross contaminate and affect the outcome of another section of the lab. Hypothesis: 1. If a substance contains lipids then when rubbed onto a paper bag a transparent or opaque spot will appear. 2. Is a substance contains starches then when iodine solution is added to the substance it will change from yellow-brown to blue-black.
For every 20 drops of solution you will add 0.1g of zinc to the new test tube. Repeat steps 3 and four until the solution is clear. If there ever exists too little of the solution to get enough drops, add up to 1mL of distilled water to the solution. 4. Once the solution is clear, retrieve at least ten drops of the solution and place them in a new test tube.
Add 10 ml of ph 10 buffer to the same Erienmeyer flask. Start swirling immediately to dissolve, 7. Add 15 ml of water next. Use a squeeze bottle so you can wash the inside walls of the flask. 8.
Another source of rennin is junket tablets, which are used in setting milk into a solid junket or dessert. Junket tablets are used as a source of rennin in this experiment. Materials (per group) (This experiment may be done in groups of four. Each student can look after two temperature set-ups.) » 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.