Introduction: Thyme contains a surprising amount of iron compounds. This experiment enables us to determine the amount of iron(II) present in dried thyme by means of a redox reaction. Method: 1. Weigh accurately about 1g of dried thyme and put into a 250cm3 beaker. Record the mass of thyme used.
(b) Calculate the volume of 0.2M UO3- needed to react with 20.00 cm3 of 0.1M Cr2O72-. 3. 24.40 g of hydrated iron(II) sulphate, FeSO4.xH2O was dissolved and made up to 1.0 dm3 of aqueous solution, acidified with sulphuric acid. 25.00 cm3 of the solution was titrated with 20.00 cm3 of 0.022M potassium manganate(VII) solution for complete oxidation. a) Write the equation for the reaction.
Calculate the surface area of the circle formed (πd2/4): Surface area = .785 cm2 2. Calculate the number of molecules on the top layer. We must convert the surface area in centimeters squared to nanometers squared and then multiple that by the surface area of a sodium stearate molecule. Convert the surface area of the circle formed (#1) to molecules per layer using the matrix below: Answer = 4.76*10^14 molecules/top layer 3. Calculate the concentration of grams of sodium stearate per milliliter of diluted solution.
How many grams of CO2 would be liberated by complete thermal decomposition of the MgCO3 in the sample? b) How much would the residue weigh? 3. Describe the location of the hottest portion of a burner flame. The tip of the inner blue flame is the hottest portion.
b) What is the molar concentration (molarity) of ethanol in the wine? Chem 131 Solution Stoichiometry and Gas Law Problems Page 1 Problem 3 As part of some research for the product Alka-Seltzer, a researcher combines 0.840g sodium bicarbonate with 100.0 mL of 0.0500 M citric acid (H3C6H5O7). a) Write the molecular, complete ionic, and net ionic equations for this reaction (assume that each molecule of citric acid is completely neutralized). b) If the dry gas that the student actually collects occupies a volume of 0.196 L at 25°C and 1.00 atm pressure, what is the percentage yield of this reaction? c) The researcher
Percent H2O in Hydrate is equal 0.34/2.33=14.6% 3. The general formula of barium chloride hydrate is BaClg-nHZO, where n is the number of water molecules. Calculate the theoretical percent water for each value of n—divide the sum of the atomic masses due to the water molecules by the sum of all the atomic masses in the hydrate, and multiply the result by 100. Complete the table. | BaCl2 | BaCl2•H2O | BaCl2•2H2O | BaCl•3H2O | Sum of atomic masses (BaCl2) | 208.23 | 208.23 | 208.23 | 208.23 | Sum of atomic masses (nH2O) | 0 | 18.02 | 36.04 | 54.06 | Sum of atomic masses (hydrate) | 208.23 | 226.25 | 244.27 | 262.29 | Percent water in hydrate (theoretical) | 0% | 7.96% | 14.75% | 20.61% | In this lab we used a Balance, centigram
About 3mL of the wash water is collected in a small test tube. A few drops of 0.1M silver nitrate solution is added to the water to test for the presences of Cl- ions. Lastly the filter paper was placed in the dry oven to dry completely and then weighted. Calculations and observations were made and recorded. Observations The
Controlled The controlled variables of the experiment were: A. The volume and concentration of the Hydrochloric acid. B. The concentration of the Sodium Hydroxide. Equipment List * Boiling Tube * 10 cm3 1mol dm-3 Hydrochloric Acid (HCL) * 15 cm3 1mol dm-3 Sodium Hydroxide (NaOH) * pH and Temperature Probes * Data Logger * Measuring Cylinder ‘ * Boiling Tube * Teat Pipette Method * Add 10ml of Hydrochloric acid, measured in a measuring cylinder, into a boiling tube.
Recrystallise the crude ester from methanol using a quantity of hot solvent approximately twice the minimum required for complete solution (This is to ensure that the phenyl benzoate does not separate until the temperature of the solution has fallen below the melting point of the ester). Phenyl benzoate separates as colourless crystals. 5. Determine the melting point of the product. Results : Yield (mass in gram) = __________________0.128 g_____________________ Melting point of pure phenyl benzoate (OC) = ___________70O______________ Melting point of your phenyl benzoate (OC) = ___________69O______________ Questions : 1.