Chemistry question and answers for September 23, 2023
- Q Which of the following statements areincorrect?a) The main source of NOx in the stratosphere is the reaction ofO(1D) with N2Ob) Some ClOx in the stratosphere is produced by photolysis ofCH3Cl...
- Q Consider the following reaction: S↔P where the rate constant forthe forward reaction is k1, and the rate constant forthe reverse reaction is k2, and Keq= [P]/[S]Which of the following would...
- Q An analytical chemist decides toanalyze a given sample spectrophotometrically for its coppercontent.  The chemist knows that copper(I) ions form acolored coordination complex with neocuproine (ncup),C14H12N2, in a one-to-two ratio,Cu(ncup)2+.  The chemist also...
- Q When 6.104 grams of a hydrocarbon, CxHy, were burned in acombustion analysis apparatus, 19.15 grams of CO2 and 7.842 gramsof H2O were produced. In a separate experiment, the molar mass...
- Q Complete and balance the following equations. (Use the lowestpossible coefficients. Include states-of-matter under SATPconditions in your answer.)A) H2O2(aq) +Cl2O7(aq) →ClO2− (aq) +O2(g) (basic solution)B) Cr2O72-(aq) + I− (aq) → Cr3+(aq)...
- Q In zero reaction, the decomposition of ammonia gas on atungsten surface has a rate of 22.3 x10-4 moles liter-1 minute-1 at1100 K when the concentration of the NH3 = 0.01Ma....
- Q why do we not need to determine the exact volume of water neededto make the solution with the KHP in the standardizationtitration?
- Q provide an example of an application when you would select usingraman spectroscopy instead of IR
- Q Calculate the partial pressure (in atm) of CH3Br atequilibrium when 2.01 atm of CH3OH and 2.01 atm of HBrreact at 1000 K according to the following chemical equation:CH3OH (g) +...
- Q When 6.104 grams of a hydrocarbon, CxHy, were burned in acombustion analysis apparatus, 19.15 grams of CO2 and 7.842 gramsof H2O were produced. In a separate experiment, the molar mass...
- Q A mixture of H2 and He are in a 10.0 L vessel at 273 K. Thetotal pressure is 756 torr. What is the partial pressure of H2 inthe vessel if...
- Q A student must make a buffer solution with a pH of 1.00.Determine which weak acid is the best option to make a buffer atthe specified pH.formic acid,Ka = 1.77 x...
- Q 3. A student makes a solution for analysis by mixing 5.172 gramsof Cu2SO4 into 500 grams of water. The density of water at thetemperature of the lab at the time...
- Q Buffer capacity is a measure of a buffer solution's resistanceto changes in pH as strong acid or base is added. Suppose that youhave 145 mL of a buffer that is...
- Q list 3 reasons you would use hplc instead of gc for organiccompounds
- Q NMR Spectroscopy QuestionGiven the compound:C18H24O3And the information of the Hydrogen and Carbon NMRSpectroscopy1H: 10.1, doublet, 1; 7.2, singlet, 1; 2.4, quartet,1; 1.5, quint, 2; 1.2, t, 313C: 199, 130, 125,...
- Q When 5.00 grams of sodium hydroxide dissolves in 100. grams ofwater the temperature rises from 25.0 oC to 38.0 oC. Is thisreaction endothermic or exothermic? EXPLAIN. Calculate the value of∆H...
- Q Calculate ΔHrxn for the following reaction:Fe2O3(s)+3CO(g)→2Fe(s)+3CO2(g)Use the following reactions and given ΔH′s.2Fe(s)+3/2O2(g)→Fe2O3(s), ΔH =-824.2 kJCO(g)+1/2O2(g)→CO2(g), ΔH =-282.7 kJ
- Q Biphenyl, C12H10,C12H10, is a nonvolatile, nonionizing solutethat is soluble in benzene, C6H6.C6H6.At 25 ∘C,25 ∘C, the vapor pressure of pure benzene is 100.84Torr. What is the vapor pressure of a...
- Q 1a. determine the pH of a citrate buffer that is 0.14 M citricacid (H3C6H5O7) and 0.18 M sodium citrate (NaH2C6H5O7). (What if itwere 0.14 sodium citrate and 0.18 M disodium...
- Q Calculate the Delta Ho , Delta So Delta Ssurroundings, Delta S universe and Delta Go for thefollowing reaction at 25 oC:2 NiS (s) + 3 O2 (g) --- > 2...
- Q Suppose 25.0g of potassium chloride is dissolved in 350.mL of a0.60 M aqueous solution of ammonium sulfate. Calculate the finalmolarity of chloride anion in the solution. You can assume thevolume...
- Q It takes 150mL of 5M sodium hydroxide to neutralize 250mL ofsulfuric acid. What is the concentration of the sulfuric acid?
- Q A solution of household bleach contains 5.25% sodiumhypochlorite, NaOCl, by mass. Assuming that the density of bleachis the same as water, calculate the volume of household bleach thatshould be diluted...
- Q Determine the values required to prepare 50.0 mL of a solutionthat buffers at a pH of 4.74.1. Volume of 0.10 M Acetic Acid needed?2. Volume of 0.1 M sodium Acetate...
- Q The “Zebra†cell was invented in 1985 in South Africa as part ofthe “ZEolite Battery Research Africa†project, and is used inall-electric municipal buses and other vehicles. It uses nickel...
- Q How many grams of potassium chlorate decompose to potassiumchloride and 932 mL of O2 at 128°C and 684 torr?2 KClO3(s) → 2 KCl(s) + 3 O2 (g)
- Q 7.50 g of NH4Cl is added to 16.6 g of water. Calculate the molalityof the solution.Please show all steps!
- Q A powder contains benzoic acid mixed with starch. A studentfinds that a 2.69 g sample of this powder requires 44.31 mL of a0.101M sodium hydroxide solution for the acid to...
- Q 10. In an experiment, a sample was 90% decomposed in 24 min.Approximately how long would this decomposition have taken if thesample had been heated 20°C higher? (Hint: Assume the rate...
- Q Predict how the equilibrium will shift (to the left, to theright or no change) with each of the following stresses: a. 2H2 (g)+ 2NO (g) → N2 (g) + 2H2O...
- Q Calculate the pH when 54.0 mL of 0.150 M KOH is mixed with 20.0mL of 0.300 M HBrO (Ka = 2.5 × 10â»â¹)
- Q What would be the difference in reactivity if ethyl3-methylbenzoate was treated in a reduction with NaBH4 vs LiAlH4? Iknow that NaBH4 is only powerful enough to reduce ketones andaldehydes, and...
- Q Draw the molecular orbitals for the following compounds and statethe number of nodes for each along with the number of net bondinginteractions.1.) cycloprpenyl cation2.) cyclopropenyl anion3.) cyclobutadiene dianion4.)cyclopentadienyl cation5.)cyclopentadienyl anion6.)...
- Q 1) How many grams of solid potassiumcyanide should be added to 1.50 Lof a 0.236 M hydrocyanic acidsolution to prepare a buffer with a pH of 10.287?grams potassium cyanide =______g.-2)...
- Q You need 700. mL of a 5.0 % (m/v) glucose solution. If you havea 29 % (m/v) glucose solution on hand, how many milliliters of thissolution do you need?
- Q Use the Henderson-Hasselbalch equation to calculate the pH ofeach solution:a) a solution that is 0.170M in HC2H3O2 and 0.125M inKC2H3O2Express your answer using two decimal places.b) a solution that is...
- Q Calculate the theoretical amounts of 0.1000 M NaOH titrant usedto titrate 0.8 and 0.9 g KHP. please show work!
- Q Cyclohexanol is converted to cyclohexanone using hypochlorousacid. Excess hypochlorous acid is removed by adding sodiumbisulfite. The aqueous reaction mixture is then saturated withsodium chloride and placed in a separatory funnel...
- Q How \"wastage reactions\" can be minimized by taking into accountsuch factors1) radical stability, 2) radical 1/2 life, 3) monomerreactivity?
- Q Which of the following is a redox reaction? More than one answermay be correct.HBr(aq) + KOH(aq) → H2O(l) + KBr(aq) SO3(g) + H2O(l) →H2SO4(aq)HBr(aq) + Na2S(aq) → NaBr(aq) + H2S(g)NH4+(aq)...
- Q Some free radical chemical reactions start with thephotodissociation of I2 molecules into Iodine atoms (gas phase) bylight with a wavelength shorter than about 792nm. A 100.0mL glasstube, pressure= 55.7mtorr and...
- Q What means charge based separationmethod in analytical chemistry?
- Q 1. A solution of magnesium hydroxide is prepared by dissolving361.824 mg of Mg(OH)2 in 273.5 mL of water. What is the equilibriumconcentration of OH- in this solution?For magnesium hydroxide, Ksp...
- Q Liquid octane CH3CH26CH3 will react with gaseous oxygen O2 toproduce gaseous carbon dioxide CO2 and gaseous water H2O. Suppose94. g of octane is mixed with 161. g of oxygen. Calculate...
- Q Assuming the water sample has a pH of 7.2, determine the amountof HOCl and OCl- in mg/L contained in the free chlorine residual ofthe treated sample.
- Q A solution is prepared from 4.5750 g of magnesium chloride and43.248 g of water. The vapor pressure of water above this solutionis found to be 0.3626 atm at 348.0 K....
- Q Describe how the solvents worked as the mobile phase of theliquid chromatography experiment. Why was it necessary to usedifferent concentrations of aqueous isopropanol in thestep-gradient separation?
- Q CH4 + O2-----CO2 +2H2O suppose 2.8 mol methane is allowed toreact with 3 mol of oxygen A) what is the limiting reactant? B) howmany moles of CO2 can be made...
- Q The activation energy for the reaction H2(g) + I2(g) ? 2 HI(g)is 167 kJ/mol, and ?E for the reaction is +28 kJ/mol. What is theactivation energy for the decomposition of...
- Q Liquid hexane CH3CH24CH3 reacts with gaseous oxygen gas O2 toproduce gaseous carbon dioxide CO2 and gaseous water H2O. If 0.664gof water is produced from the reaction of 1.7g of hexane...
- Q A 26.9 mL sample of 0.373 Mtriethylamine,(C2H5)3N, istitrated with 0.310 M hydroiodicacid.The pH before the addition of any hydroiodic acidis .  Use the Tables link in the References for anyequilibrium constants...
- Q A) A 52.0-mL volume of 0.35 M CH3COOH (Ka=1.8×10−5) is titratedwith 0.40 MM NaOH. Calculate the pH after the addition of 17.0 mLof NaOH.B) Calculate the molar solubility of lead...
- Q Part AConsider the second-order reaction:2HI(g)→H2(g)+I2(g)Rate law: k[H]^2k= 6.4*10^-9 (mol*s) at 500 KInitial rate = 1.6 * 10^-7 mol (l*s)What will be the concentration of HI after t =3.65×1010 s ([HI]t)...
- Q Glycolysis1)describe the Schiff-base role in aldolase2)Describe the role of the thioester intermediate in G3Pdehydrogenase3) Describe the differences between glucokinase andhexokinase4) Describe the reactants/products/regulation for the threeirreversible reactions in glycolysis (1,...
- Q Determine the limiting reagent and calculate the theoreticalyield if 0.96 g of benzyltriphenylphosphonium chloride is reactedwith 0.30 mL of cinnamaldehyde. Â
- Q A 1.38 L buffer solution consists of 0.193M butanoic acid and0.350 M sodium butanoate. Calculate the pH of the solutionfollowing the addition of 0.0680 of NaOH. Assume that anycontribution of...
- Q What is the purpose of sulfuric acid, hydroxylaminehydrochloride and sodium acetate in 1, 10-phenanthrolinedetermination of total iron? Also provide the balanced equation forhydroxylamine hydrochloride in this experiment.(NH4)2Fe(SO4)2・6H2Ois given. Sulfuric acid...
- Q This is from an experiment simulating a breathalyzer. Potassiumdichromate standard is 0.625 mg/mL in 9M sulfuric acid. We areusing the equation 3 C2H5OH + 2 K2Cr2O7 + 8 H2SO4→ 3...
- Q Draw the Lewis structure of AsO43– showing all lone pairs.Identify the molecular geometry of AsO43–. What is thehybridization of the central As atom? What are the approximate bondangles in AsO43–?...
- Q How many GRAMS of carbon are present in 4.00 moles of carbondioxide, CO2?How many MOLES of oxygen are present in 3.11 grams of carbondioxide?How many GRAMS of oxygen are present...
- Q Partial Pressure QuestionA. A mixture of krypton andoxygen gases, in a 9.68 L flaskat 34 °C, contains 8.73 grams ofkrypton and 8.09 grams ofoxygen. The partial pressure ofoxygen in the...
- Q Answer the following questions pertaining to the followingequation. 4Ga + 3S2 -> 2Ga2S31. How many moles of Sulfur are needed to react with 12.5 molesof Gallium2. How many moles of...
- Q Show your work!1. How much energy is in a beta-Lyman emission of hydrogen?2. The gamma Lyman emission of hydrogen corresponds to anelectron dropping from which energy level to which other...
- Q A 20.00 mL solution of 0.200M diprotic acid (H2A,pKa1=3.500, pKa2=8.500) is titrated with0.250M KOH. Sketch the titration curve for this titration. Labelthe x-axis, y-axis, pKa's, and equivalence points.
- Q Consider the decomposition of barium carbonate:BaCO3(s)???BaO(s)+CO2(g)A) Calculate the equilibrium pressure of CO2 at 298 K.B) Calculate the equilibrium pressure of CO2 at 1300K .
- Q Potentiometry is to be used to determine the concentration of ametal dication, M2+,in water. The table below shows the dependence of the cellpotential on [M2+](please note some data has been...
- Q Pre-lab questions:Q 1. Based on the Three Source of ErrorThree sources of error in acid-base titration1. We notice the colour change of the solution due to presenceof indicator at the...
- Q balance each equation.Mg(s)+HBr(aq) ------ MgBr2(s) + H2(g)B. CO(g) + O2(g) ----------CO2 (g)c. PbS (s) + O2 (g) ---------PbO (s) + SO2(g)d.H2SO4 +NAOH -------- Na2SO4 +H2Oe. H3PO4 +Ca (OH)2--------CA3 (PO4)2+ H2O
- Q A) For the gas phase decomposition of hydrogen iodide at 700 K 2HIH2 + I2 the average rate of disappearance of HI over the timeperiod from t = 0 s...
- Q Consider the combustion of propane gas, C3H8(g) + 5O2(g) 3CO2(g)+ 4H2O(l) Ho = -2,220 kJ/mol Propane (just C3H8) is often used forgas grills. Anyone who has every filled or moved...
- Q Kp for the equilibrium N2(g)+ 3H2(g) <> 2NH3(g) is 4.51 x10^-5 at 450C. For each of the mixtures listed here, indicatedwhether the mixture is at equilbrium at 450C. If it...
- Q Calculate the mass percent of a NaCl solution in which 141 g ofNaCl is dissolved in 4.00 L of water at 25 ∘C (density = 0.997g/mL).Express your answer numerically.
- Q The He+ ion contains only one electron and istherefore a hydrogen-like ion. Calculate the wavelengths of thefirst four transitions in the Balmer series of the He+ion. List your answers in...
- Q The pH of 0.1M NaCl is 7.14. After 1 drop of 0.1M HClthe pH change to 3.59. And after another 1 drop of 0.1M HCl the pHbecome 3.13.Why does pH...
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