Chemistry question and answers for August 27, 2023
- Q Physical Chemistry Thermodynamics:The enthalpy of combustion of benzoic acid (C6H5COOH) iscommonly used as the standard for calibrating constant-volume bombcalorimeters; its value has been accurately determined to be—3226.7 kJ mol-1, (a)...
- Q 7-25 mL of 0.25 M HC2H3O2 are titrated with 0.25 M NaOH. a.Whatis the pH after 0mL of NaOH have been added? b.What is the pH after15mL of NaOH have...
- Q Conformational analysis of a molecule was performed using aglobal-optimisation method where the energy was evaluated usingHartree-Fock (HF) theory. The binding energy of the low-energyconformers with a host complex was then...
- Q A certain weak base has a Kb of 7.40 × 10-7. What concentrationof this base will produce a pH of 10.07?
- Q What is the solubility ( in g/L) of lead(II) chromate, PbCrO4 in0.13M potassium chromate, K2CrO4.
- Q Question #1.) An unknown liquid requires 7.72 kJ of energy tochange 12.4 grams 10.00 degrees C. Calculate the specific heat ofthe material.Question #2.) Use the standard heats of formation from...
- Q The inside of a cell is extremely crowded. We will try to gainsome insight for exactly how crowded by considering some numbersthat are estimates of the situation in the common...
- Q Determine the pH of an HNO2 solution of each of the followingconcentrations.0.540 M0.100 M1.30×10−2 MIn which cases can you not make the simplifying assumption thatx is small?
- Q Qualitative scheme for seperation of ions Ag, Pb2+, Fe3+, Cu2+,Al3+, Mn2+, Ni2+, Ba
- Q How many N2 molecules in your next breath were present in JuliusCaesar’s last breath (died in 44 BC, March 15 in Rome)?a) First find the probability of the N2 in...
- Q Describe the response mechanism of the fluoride-ion-selectiveelectrode. Explain why the OH- is the major interfering ion in F-ISE measrements.
- Q Radiolytic decomposition of water on the coolant side ofzirconium cladding is generating a pressure of H2 of 10-4 bar withthus a similar surface concentration of H2. Hydrogen, H2, is thusdiffusing...
- Q Compare the number of moles of nitrogen-oxygen species in aircontaining 300 ppbv nitric oxide, with fog consisting of 10,000droplets per cm^3, having an average diameter of 2 um, andcontaining nitrate...
- Q 2a)Â Â Consider the following reaction:3NaHCO3(aq) + H3C6H5O7(aq) ï‚® 3CO2(g) + 3H2O(l) +Na3C6H5O7(aq)If 1.00 grams of NaHCO3 reacts with 1.00 grams of H3C6H5O7, what isthe limiting reagent?2b What mass of water...
- Q For each of the following, determine the FOS and dnconfiguration for the transition metals. Be sure to clearly showthe FOS and/ or charges for all relevant ligands and species.A. Cr(OH2)3(OH)3B....
- Q When 43.7 g g of KClO3 K C l O 3 is completely decomposed, whatis the theoretical yield, in grams, of O2 ?Express your answer with the appropriate units.If 12.1...
- Q If 100 mL of 1.0 M sulfuric acid, H2SO4, is neutralized with 1.0M calcium hydroxide, Ca(OH)2, how many mL of base must beadded?
- Q We will assay enzyme activity at 340 nm. The molar absorbance ishigher at 260, meaning we can detect three times less cofactor. Whydon’t we use that wavelength? If you had...
- Q a. What is the pH of the buffer prepared by mixing 250. mL of0.200 M benzoic acid and 100. mL of 0.250M NaOH? pKa=4.19b. A buffer containing 1.00 M concentrations...
- Q If the atmospheric burden of CO2 increases by 18.0 Gt(gigatonnes, 1Gt= 1 x 1012 kg) over a given period oftime, starting now, and the current atmospheric CO2 is408.3 ppm, what...
- Q 1. why does olive oil have a lower melting point than butterfat?2. how does LDL differ from HDL's3. In a helix, how does bond occur between the amino acids inthe...
- Q . Suppose that you are preparing CaCl2 solutions.a. What mass of CaCl2(s) would you need to add to make 100.0 mLof a 0.020 M solution?b. If you actually added 0.228...
- Q We’re going to titrate formic acid with the strong base, NaOH.There is initially 100. mL of 0.50 M formic acid and theconcentration of NaOH is 1.0 M.A. What is the...
- Q what is the relationship between volatility and the vaporpressure of a solvent
- Q A chemist titrates 30.0 mL of 0.840 M hydroxylamine, HONH2 Kb =1.1 x 10–8 , with 0.900 M HNO3. Calculate the pH at each of thefollowing volumes of added titrant.12.0...
- Q Important equations for making up solutionsWeight of solute (g) = formula weight of solute (g/mole)x molarity (mol/l) x final volume (L)C1V1 =C2V2How to make solutionsChoose the correct formula from above....
- Q ineach of the following reactions, identify the reactant that isoxidized and the reactant that is reduced.A.) Ba(s)+Cl2(g)->BaCl2(s)B.) Br2(g)+2KCl(aq)->2KBr(aq)+I2(s)C.) 2Al(s)+3Sn^2+(aq)->2Al^3+(aq)+3Sn(s)D.) Fe(s)+Pb(NO3)2(aq)->Fe(NO3)2(aq)+Pb(s)
- Q What is the equivalence point pH for the titration of 25ml 0.80Mdiethyleneamine (kb = 5.9x10-4) titrated by 0.60M strong acid? A.3.74 B. 5.62 C.6.55 D. 8.62
- Q When a pink aqueous solution of potassium permanganate, faintlyacidified with dilute sulfuric acid was treated with 10% aq.hydrogen peroxide, the reaction took place with the evolution ofgas bubbles, and the...
- Q A student collected the following data as part of theDetermination of KClOx:Temperature: 23.0 oCAtmospheric Pressure: 749.3 torrPH2O: 21.454 torrVolume of O2: 89 mLMass of KClOx: 0.372 ga. Determine the moles...
- Q ConstantsHeat of fusion (?Hfus) is used for calculationsinvolving a phase change between solid and liquid, with notemperature change. For H2O, ?Hfus=6.02 kJ/mol.Specific heat capacity (C) is used for calculationsthat involve...
- Q Industrial chemists make hydrofluoric acid (which is used inaluminum and uranium processing, to etch glass, and to make CFCs)from the reactions of aqueous calcium fluoride and aqueous sulfuricacid. Write the...
- Q 1) Each molecule of testosterone contains 19 atoms of carbon(plus other atom). The mass percent of carbon in testosterone is79.12%. What is the molar mass of testosterone?2) A substance contains...
- Q Complete and balance the following equations, and identify theoxidizing and reducing agents. (Use the lowest possiblecoefficients. Include states-of-matter (s), (l), (g), (aq) similarto the given reaction.)a.)Â Â MnO4-(aq) +CH3OH(aq) ? Mn2+(aq) +HCO2H(aq)...
- Q Complete the following table:Ppm               Grams                       Air Volume(l)            Mol.Wt. (g)_______       0.02542                         75                             3392                   0.00228                        300 _____1000               7.164 _____ 1460.002 _____ 2650 254
- Q A buffer solution is composed of 1.905 g of KH2PO4 and 5.181 gof Na2HPO4. ( Ka for dihydrogen phosphate ion is 6.2x10^-8 .)a. What is the pH of the buffer...
- Q I need to write a lab plan based on preparing a standardsolution-- Standardization of NaOH (aq)Experiment 8: Preparing a Standard Solution—Standardization ofNaOH(aq) Learning Objectives » to understand the meaning of...
- Q Suppose a particular mechanism has the following equilibria:Ni(CO)4(g) ⇌Ni(s) + 4CO(g)              K1 =8.77            ΔH1 = 190 kJMnO(s) + CO(g) ⇌Mn(s) +CO2(g)       K2 =490             ΔH2 = 349 kJMn(s) +H2O(g) ⇌ MnO(s) +H2(g)        K3 =0.0149         ΔH3 = -346...
- Q 8.03 x 10^23 moleucles of oxygen react with excess nitrogen.what is the maximum number of grams of dinitrogen tetroxide thatcan be produced?42 grams of cyclohexane burns in excess air to...
- Q A beaker with 1.10×10^2 mL of an acetic acid buffer with a pH of5.000 is sitting on a benchtop. The total molarity of acid andconjugate base in this buffer is...
- Q Use the following thermodynamic data to calculate ∆S°(universe) for the formation of HBr(g) from its elements at 298K inJ/K.  HINT: write the formation reaction forHBr(g)Species       ∆Hf° (kJ/mol)       S°(J/Kmol)                 Species     ∆Hf°(kJ/mol)     S° (J/Kmol)HBr(g)          -36.3                 198.59                             Br2(g)         30.91              245.38Br2(l)                0                  152.23                             H2(g)            ...
- Q 10) Aluminum doesn’t readily corrodebecause:a) its standard reduction potential is more positive thanoxygenb) its standard reduction potential is more negative thanoxygenc) it forms a dense coating of alumina,Al2O3, that slows...
- Q Onetablet of extra-strength Excedrin contains aspirin, acetaminophen,and caffeine. To isolate the three components, you had to extractthe solution including ether and the three components first withK2HPO4 and then afterwards with...
- Q Arrange the following 0.10 Msolutions in order of increasing acidity: (i) NH4NO3, (ii)NaNO3, (iii) CH3COONH4, (iv) NaF, (v) CH3COONa.
- Q 12. Calculate the pH of a buffer solution made from 0.30 Mhydrofluoric acid and 0.70 M sodium fluoride after the addition of0.08 mol of NaOH to 1.0 L of this...
- Q Balance the following aqueous reactions:a. CrI3 + Cl2 ----->CrO42- + IO41- +Cl1- (basic solution)b. Cr(NCS)64- + Ce4+ ---->Cr3+ + Ce3+ + NO31- +CO2 + SO42- (acidic solution)
- Q There are several classifications of chemical reactions. Pleaseresearch a reaction and provide its particular classification andcharacterization(s).
- Q To a 100.0mL volumetric flask are added 1.00 mL volumes of threesolutions: 0.0100 M AgNO3, 0.190 M NaBr, and 0.100 M NaCN. Themixture is diluted with deionized water to the...
- Q A 300mL buffer is prepared in which [HCO3-] = 0.2M and[CO3^2-]=0.075M.a) What is the pH of this buffer (Ka HCO3-=4.7x10^-11)?b) What is the pH of the buffer if 0.0100 moles...
- Q Balance the following,in basic solution, by the method of half reactions.C2H5OH +MnO4--->C2H3O2-+MnO2,What is thecoefficient on water (H2O) in the product of thebalanced equation?
- Q Considering a solution that is made from mixing 35ml of 0.22M AgNO3and 83ml of 0.22M Na2SO4?a) how much silver sulfate forms?b) what is the concentration of silver ions and sulfate...
- Q Structural data evolves with time, even for simple molecules.Consider the compounds E(CF3)3, i.e, thetris(trifluoromethyl) derivatives of P, As, and Sb. C-E-C bondangles were determined by gas-phase electron diffraction in themid-20th...
- Q Why can a heavy-water moderated reactor use a lower enrichmenturanium fuel than a light water moderated reactor?
- Q What is the lead (II) ion concentration in a solution preparedby mixing 341 mL of 0.363 M lead (II) nitrate with 379 mL of 0.359M sodium fluoride? The Ksp of...
- Q Part C - Describe how a white light sourcecould be engineered using CdSe quantum dots.
- Q You are making a stock salt solution by diluting 0.7563g of saltto 500mL with water.a) What is the analytical concentration (in mol/L) if the saltis sodium chloride?b) What is the...
- Q I already answered the first three questions and put theanswer down I just don't know how to answer the last question whichasks to calculate K in the rate law?A clock...
- Q Hexokinase catalyzes the first step of glycolysis, in whichglucose is phosphorylated to form glucose-6-phosphate. Which of thefollowing statements are accurate? Choose all that apply.Hexokinase is found in the mitochondrial membrane.Hexokinase...
- Q Answer the following questions:a). The heat of fusion of ice is 6.00 kJ/mol. Find thenumber of photons of wavelength = 6.27 10-6 m that must be absorbedto melt 3.00 g...
- Q A 35.0-mL sample of 0.150 M acetic acid (CH3COOH) istitrated with 0.150 MNaOHsolution. Calculate the pH afterthe following volumes of base have been added.35.5 mLExpress your answer using two decimal...
- Q At 800K, 2 mol of NO are mixed with 1 mol of O2. The reaction2NO(g) + O2(g) <---> 2NO2(g) comes to equilibrium under atotal pressure of 1 atm. Analysis of...
- Q 1-sec-butoxy-3-chloro-1-methylcyclohexanea) Draw structureb) Draw all possible stereoisomers with R/S designation andlabel them A,B, C, etc.c) List the enantiomers:d) List the diastereomers:e) List the meso compounds:
- Q (a) How many milliliters of 0.165 M HCl are needed to neutralizecompletely 25.0 mL of 0.101 M Ba(OH)2 solution? 30.6 Correct: Youranswer is correct. ml (b) How many milliliters of...
- Q . Mg2+ ions are present in seawater, and the metal is oftenprepared by \"harvesting\" these ions and converting them to neutralMg metal. The average magnesium content of the oceans is...
- Q Question 2Tyrosine is a triprotic amino acid with pKa of 2.17, 9.19, and10.47 The first proton is removedfrom the carboxylic acid ( –COOH), the second from theprotonated amine group (–NH3+)...
- Q Determine how many micrograms of phosphorus are in the followingsolutions:1. 0.02M KH2PO42. 0.3M KH2PO43. 0.5M KH2PO44. 0.8MÂ Â KH2PO45. 1MÂ Â KH2PO46. 1.3M KH2PO4
- Q Compute the volume of 0.20M silver nitrate needed to precipitatethe chloride ion in a 0.60g sample of an unknown that is 45%chloride and the mass of the solid nitrate used...
- Q When 2.14 g of a nonelectrolyte solute is dissolved in water tomake 165 mL of solution at 22 °C, the solution exerts an osmoticpressure of 821 torr.
- Q Mercury ions (Hg2+2) can be removed from solution byprecipitation with Cl−. Suppose that a solution contains aqueousHg2(NO3)2.Express your answer as a chemical equation. Identify all of thephases in your answer.A)Write...
- Q 1) Explain with halogens are deactivators, but ortho, paradirectors, instead of m directors, in an EAS reaction.2) Draw the energy diagrams for the first step of anelectrophilic aromatic substitution reactions...
- Q You measure the pH of rainwater at 5.4. Calculate the partialpressure of carbon dioxide (assume only CO2 ispresent).PLEASE BE VERY CLEAR WITH WHERE EVERYTHING COMES FROM
- Q A 25.0 mL sample of 0.30 M HCOOH is titrated with 0.20 M KOH.What is the pH of the solution after 25.0 mL of KOH has been addedto the acid?...
- Q Which substances given below produce a basic solution whendissolved in water?NaClKOHSucroseNH3VinegarSuppose an everyday chemical reacts with vinegar. Is thesubstance more likely to be an acid or a base? Justify youranswer.
- Q Determine the electron geometry, molecular geometry, andidealized bond angles for each of the following molecules. In whichcases do you expect deviations from the idealized bond angle?CF4NF3OF2H2S
- Q A 100 g piece of copper, initially at 95,0 C ,is dropped into 200 g of water. If initial temperature ofwater is 1 5 C, what is final temperature of...
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