Which of the 2 reactants is the limiting reagent C. Calculate the mass of urea formed D. How much excess reagent is left at the end of the reaction E. If the actual yield of urea formed was 980g what is its yield % a. Ans. 2NH3 + CO2 ( (NH2)2CO + H2O (17) (44) (60) 637.2 1142 980 b. HN3 c. 1124g d. 318g of CO2 e. 87.2% 1b .Iron is reduced from a reaction between aluminium and iron (III) oxide at a temperature of 3000°C. In this reaction 124g of Al and 601g of iron (III) oxide are reacted. A. Write a balance equation for the above reaction B.
(c) Calculate the mass of water formed when 20 g of methane undergoes complete combustion. 6 Deduce the empirical formulae of the following: Moles and empirical formulae 1 Calculate the molar mass of these compounds. (Relative atomic masses H = 1; N = 14; O = 16; Mg = 24; S = 32; Ca = 40; K =39; Cr = 52; Fe = 56.) (a) calcium ethanoate, Ca(CH3CO2)2 (b) chromium sulfate Cr2(SO4)3 (c) magnesium hydroxide, Mg(OH)2 (d) potassium cyanoferrate(III), K3Fe(CN)6 2 When 2.4 g of magnesium
9. A 20-mL sample of gastric fluid is neutralized by 25 mL of 0.10 M NaOH. What is the molarity of HCl in the fluid? Assume that all the acidity of the gastric fluid is due to HCl. 11.
Chemistry 11 | The Decomposition Reaction of Baking Soda, NaHCO3 | Oscar ShiPeriod 2Laboratory AssignmentDue Date: 2011/4/14 | Introduction The objective of this experiment is to find the actual chemical equation that governs the manner in which baking soda (sodium hydrogen carbonate NaHCO3) decomposes. When NaHCO3 is heated, it decomposes to produce a gas and leaves behind a solid. Two possible equations for the decomposition are: NaHCO3 (s) + heat NaOH (s) + CO2 (g) NaHCO3 (s) + heat ½ Na2OH3 (s) + ½ H2O (g) + ½ CO2 (g) Materials and Methods * electronic balance * sodium hydrogen carbonate * ring * ring stand * crucible tongs * crucible * crucible lid * clay triangles The Procedure of the Laboratory 1. Put on safety goggles and a lab apron. 2.
Purpose of the experiment: In the first part experiment 20 the purpose was to determine the change in pH, concentration of the acidic solutions, and the equilibrium constant for dissociation acid. By using several titrations, pH electrode, and titration plotted curves. In the second part experiment 21 the purpose was to determine the concentration of a weak acid in vinegar and to determine the equilibrium constant of the weak acid. Procedure: Prepare acidic solution Two bakers labeled on as KHP one as HCl for the first one 40ml of .05 M potassium hydrogen phthalate for the second beaker .1M HCl were added. 25 ml of HCl transferred to a beaker by using volumetric pipet the beaker labeled as beaker 1.
The temperature rose from 25.0°C to 34.9°C. Calculate the heat capacity, molar heat capacity and the specific heat capacity. 5) From the enthalpies of reaction N2(g) + O2(g) 2NO(g) 2NO(g) + O2(g) 2NO2(g) 2N2O(g) 2N2(g) + O2(g) H = 180.7 kJ H = -113.1 kJ H = -163.2 kJ calculate H for the reaction of dinitrogen monoxide with nitrogen dioxide: N2O(g) + NO2(g) 3NO(g) 6) a. b. Give the electronic configuration for Sn. Give the abbreviated electronic configuration for Ti.
i. What is the hydrogen concentration of a solution with a pOH of 3.7? j. What is the pH of a substance with a hydroxide concentration of 4 x 10-5? k. What is the hydroxide concentration of a substance with a pOH of 8.5?
Comparing the rate of appearance of C and the rate of disappearance of A, we get[pic]. A) [pic] B) [pic] C) [pic] D) [pic] E) [pic] Answer: A Diff: 1 Page Ref: Sec. 14.2 A flask is charged with 0.124 mol of A and allowed to react to form B according to the reaction A(g) →B(g). The following data are obtained for [A] as the reaction proceeds: [pic] 5) The average rate of disappearance of A between 10 s and 20 s is __________ mol/s. A) [pic] B) [pic] C) [pic] D) 454 E) [pic] Answer: A Diff: 1 Page Ref: Sec.
As we know the equation C1V1=C2V2, we can get a set of concentration (g/L) of different ratio of Red #40. Introduction The goal which the experiment designed to achieve is perform a Beer’s law analysis to determine a solution’s concentration, and determine a percent composition. To build the calibration curves for each food dye, we need to measure the absorption of different solutions of known concentration. One rather quick way to make a solution of known concentration is by exact dilution from a more concentrated solution of known concentration. We rinsed a pipette with some of the sample, filled curettes between 2/3 and 3/4 full with the samples, put a curette in the cell holder and make absorbance measurements.
OBJECTIVES In this experiment, you will • • • • Determine the freezing temperature of the pure solvent, lauric acid. Determine the freezing temperature of a mixture of lauric acid and benzoic acid. Calculate the freezing point depression of the mixture. Calculate the molecular weight of benzoic acid. Figure 1 MATERIALS Data Collection Mechanism Temperature Probe ring stand 400 mL beaker Tissue or paper towels lauric acid, CH3(CH2)10COOH lauric acid-benzoic acid mixture hot water bath utility clamp two 18 × 150 mm test tubes (if pre-made samples are not provided by your teacher) 1 “The Computer-Based Laboratory”, Journal of Chemical Education: Software, 1988, Vol.1A, No.