Stoichiometry Practice 1. Calculate the mass of silver bromide produced from 22.5 g of silver nitrate in the following reaction: 2AgNO3(aq) + MgBr2(aq) ( 2AgBr(s) + Mg(NO3)2(aq) ans: 24.9 g AgBr 2. What mass of acetylene, C2H2, will be produced from the reaction of 90. g of calcium carbide, CaC2, with water in the following reaction? CaC2(s) + 2H2O(l) ( C2H2(g) + Ca(OH)2(s) ans: 37 g C2H2 3. Chlorine gas can be produced in the laboratory by adding concentrated hydrochloric acid to manganese(IV) oxide in the following reaction: MnO2(s) + 4HCl(aq) ( MnCl2(aq) + 2H2O(l) + Cl2(g) a.
(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.
What mass of MgCO3 is contained in a 2.750g solid sample consisting of only MgCO3 and MgO if heating to decompose all the MgCO3 according to the following equation leaves a solid residue weighing 2.160g? Magnesium oxide is unaffected by the heat. MgCO3(s) MgO (s) + Co2 (g) 2. a) Consider the reaction of question 2. Suppose a 3.250 g sample containing only MgCO3 and MgO is 42.6% MgO. How many grams of CO2 would be liberated by complete thermal decomposition of the MgCO3 in the sample?
What is the identity of the element Z? The two reactions are: Z(OH)2(s) + 2HCl(aq) →ZCl2(aq) + 2H2O(l) HCl(aq) + NaOH(aq) →NaCl(aq) + H2O(l) [Ans. : Mg, calculated molar mass 24.31 g] 6) A sample of “compound X,” known to contain only C and H, was burned and the resulting CO2 and
Solution Stoichiometry and Gas Law Problems Problem 1 In flask A, 1.500g of silver nitrate solid is dissolved in 50.0mL of water, while in flask B, 0.500g of potassium carbonate is dissolved in 25.0mL of water. The two solutions are then mixed together. a) Before mixing, what is the molarity of each solution? b) Write the balanced molecular equation, the complete ionic equation, and the net ionic equation for the reaction. c) If the percentage yield is 85.0%, what mass of precipitate is actually produced?
The following data were obtained when a sample of barium chloride hydrate was analyzed as described in the Procedure section. Calculate (a) the mass of the hydrate, (b) the mass of water lost during heating, and (c) the percent water in the hydrate. Mass of empty test tube 18.42 g Mass of test tube and hydrate (before heating) 20.75 g Mass of test tube and anhydrous salt (after heating) 20.41 g. Mass of the Hydrate is 2.33g. Loss (H2O) is 0.34g. Percent H2O in Hydrate is equal 0.34/2.33=14.6% 3.
Micro – scale Reduction of a Ketone to an Alcohol: Benzophenone to Diphenylmethanol with Sodium Borohydride Abstract: Purpose of experiment 2.1 was to perform reduction reaction of benzophenone to diphenylmethanol with sodium borohydride as a reducing agent. The reducing agent was used in excess to ensure complete reduction of the carbonyl group. The product was isolated as a solid by filtration and its purity was checked using Thin Layer Chromatography with different ratios of mixture of polar and non – polar solvents and by checking its melting point, which was 520C - 620C. Infra – Red spectroscopy was not performed, however previously printed graphs were compared and analysed based on tables in Chemistry Laboratory Manual. Purpose of the Experiment: To produce diphenylmethanol from the reduction of benzophenone by using sodium borohydride as a reducing agent.
00.0602 grams of the product were obtained. The boiling point range of the pure product was found to be 131-136ºc. An IR of the product was obtained. Observations When the aluminium chloride was added to the flask a series of colour changes occurred during which time there was an evolution of hydrogen chloride. The reaction mixture turned yellow to dark green to brown, until it eventually turned almost black.
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.