To do this, first take the number of drops used to achieve the monolayer (1 drop) and convert it to mL using the calibrated number of drops per mL. Then multiply the number of grams of sodium stearate per milliliter of solution. Finally, convert to moles through the molar mass of sodium stearate. HINT: The molar mass of sodium stearate is 296.5 g/mole. Answer = 1.06*10^7 moles/top layer 5.
Place 10 drops of zinc nitrate into A3 of the 24 well plate. 5. Place 10 drops of iron (III) chloride into A4 of the 24 well plate. 6. Place 10 drops of copper (II) sulfate into A5 of the 24 well plate.
Prepare the apparatus according to diagram A. 2. Prepare 100 cm3 of 0.2 M hydrochloric acid by mixing 10 cm3 of 2 M hydrochloric acid with 90 cm3 of distilled water. 3. Fill the conical flask with 50 cm3 of 0.2 M hydrochloric acid.
Using a measuring cylinder, add 50cm3 of 1.0mol dm-3 sulphuric(VI) acid to the thyme extract in the conical flask. 8. Titrate the solution in the conical flask with the potassium manganate(VII) solution until a pale pink colour persists for 10 seconds. 9. Repeat the titration until there are two titres within 0.1cm3 of each other.
Calculate the percent error in the molar mass value. Enter both values in the Data Table. Molar Mass Na2CO3 = 105.99 g/mol – this is the closest molar mass to what I calculated, so the unknown M2CO3 must be sodium carbonate. Percent Error: 93.08g/mol – 105.99 g/mol (100) = 12.18% error 105.99 g/mol DISCUSSION Review the procedure and list the possible sources of error that would cause either the molar mass of the unknown to be (a) too high or (b) too low. The goal of this lab was to discover the unknown group 1 metal (M) of the compound M2CO3 by dissolving the compound in water and adding a solution of calcium chloride, CaCl2 to the solution in order to precipitate the carbonate ions to reveal the molar mass of the unknown element, thus determining the identity of the unknown element.
Add 10mL of unknown salt and water solution. Weigh beaker and solution, record weight. Under a Bunsen burner place the beaker put a thermometer in beaker. Increase in temperature shows that the water is heating up. As the water begins to boil, record the temperature.
Pound o B. Slug o C. Ounce o D. Gram 2. 2. Based on the image, what is the mass of the object being measured? o A. 500.1 grams o B.
What is the percent yield of the reaction? [Ans. : 43.21] 3) A 5.6780 gram sample of the compound Na2XO3 was dissolved in water then reacted with excess calcium chloride: Na2XO3(aq) + CaCl2(aq) →CaXO3(s) + 2NaCl(aq) A total of 5.4842 grams of CaXO3 were collected. What is the identity of the element “X?” [Ans. : Se, calculated molar mass 78.93 g] 4) A 0.3528 gram mixture of H2SO4 (molar mass 98 grams) and H3PO4 (molar mass 98 grams) was mixed with a little water and titrated with 9.70 mL of 1.000 M NaOH: 3NaOH(aq) + H3PO4(aq) →3H2O(l) + Na3PO4(aq) 2NaOH(aq) + H2SO4(aq) →2H2O(l) + Na2SO4(aq) What was the percent by mass H2SO4 in the original mixture?
Once the buffer tablet has dissolved into the water, add 10 ml of starch solution. 3. After the starch solution has been added, add 10 ml of enzyme solution to the current solution, simultaneously start the timer and record at 1 minute intervals. 4. In addition, place iodine in the dropping tile in order to identify if starch is currently present.
Vapor Pressure and Enthalpy of Vaporization of Water I. List of Reagents: a. Water H2O II. Summary of Procedure: b. Fill a 10 mL graduated cylinder with ≈ 7mL if water c. Fill a 1000 mL beaker with ≈ 750 mL of water d. Invert the graduated cylinder into the beaker.