Chemistry Questions and Answers May 10, 2020

How many moles of carbon monoxide react with 1 mol of oxygen gas acording to the balanced chemical equation 2C0g) 023) A 20028) 1 mol O 2 mol O 3 mol O 4 mol O none of these

How many moles of argon gas contain 7.52 x 10 22 Ar atoms O Q.0125 mol 0.0.0801 mol O0.125mol O 0.801 mol O 1.25 mol

Derive tho symmety based wavefunctions from six cambon 2s calculate other four orthoganal wavefunctions. ocbitals f benzene. And

Sulfur dioxide reacts with chlorine to produce thionyl chloride (used as a drying agent for inorganic halides) and dichlorine oxide (used as a bleach for wood, pulp and textiles). SO2(g) 2CI2(g) SOCI2(g) Cl2O(g) If 0.600 mol of Cl2 reacts with excess SO2, how many moles of Cl20 are formed

Aluminum reacts with bromine to form aluminum bromide (used as an acid catalyst in organic synthesis). Al(s) Br2() Al2Br6(s) unbalanced How many moles of Al are needed to form 2.43 mol of Al2Br6

It was determined that 1.4 x 1024 carbon dioxide molecules are produced when propane is combusted according to the equation below. Calculate the number of moles of propane that was burned. C3 Hg 50, 3CO2 4H20 note Make sure you have the right number of sig figs. For decimal answers, make sure you write the zero. Example 0.99

Calculate how many moles of Ca(OH), are needed to produce 4.8 x 1024 NH, molecules, according to the following equation (NH,), SO, Ca(OH)2 2NH, CaSO, 2H, 0

Calculate the solubility of BaSO, (a) in pure water and (b) in a solution in which SO10.102 M. Kp(BaSO,) 1.1 x 1010 Solubility in pure water M Solubility in 0.102 M so, M

The solubility of Pb(IO,),(s) in a 2.30x10 M KIO, solution is 5.9x108 molL. Calculate the Kp value for Pb(IO,)(9).

What are the concentrations of Cu, NH3, and Cu(NH3), at equilibrium when 18.8 g of Cu(NO3), is added to 1.0 L of a 0.800 M solution of aqueous ammonia Assume that there is no volume change upon the addition of the solid, and that the reaction goes to completion and forms Cu(NH,),. K 2.0 x 1012 M 3D NH3 M Cu(NH3),) M

The Ag + ion is larger in a square planar environment than it is in a tetrahedral one. For Ni +2 the reverse is true. Explain.

Give the structure of the product formed in the following reaction and also the mechanism by using curly arrow.

cat. HCI OCH3 H2N NH2 in EIOH, heat

A 55.0 ml solution of 0.120 M potassium alaninate ( K H,NC,H,CO,K) is titrated with 0.120 M HCI. The pK, CH3 values for the amino acid alanine are 2.344 (pKa1) and 9.868 (pK2), which correspond to the carboxylic acid and H2N CH amino groups, respectively. Calculate the pH at the first equivalence point. Potassium Alaninate pH Calculate the pH at

Be sure to answer all parts A gas expands in volume from 31.8 mL to 96.3 mL at constant temperature. (a) Calculate the work done (in joules) if the gas expands against a vacuum Enter your answer in scientific notation. (b) Calculate the work done (in joules) against a constant pressure of 3.5 atm Enter your answer in scientific notation. x 10 (c)

Solve for all grey parts from H34 to M34 from H39 to M39 from H44 to M44 from H51 to M51 from H52 to M52 from H53 to M53

x v fx H24 ABC D E H. M PV Line description Units Annual Values Constants 2 Years 4. 6 3 Discount rate 10.00 32 Investment cost 33 30,000 S Equipment cost in year 1 Equipment 34 35 36 Land 37 Land required Flag 38 Rental cost of land per period 500 s 39 Land 40 41 Parts Operating periods Cost of parts per period 42 Flag 43 1,000 S 44 Parts 45 46

Provide the missing structures of products A and B for the following reaction sequence. NH2 1) NANO2, HCI HCI, H20 Product A Product B 2) NaCN Draw the structures of the products using the JSME Molecular Editor software. Enter the SMILES string for product A and product B

When aqueous solutions of CaCl, and K,so, are mixed. The true statement is Select one a. Caso, precipitates from solution 4. b. KCI precipitates from solution C. The reaction is oxidation reduction reaction 2 d. The spectator ions are K and SO e. No precipitate formed

Voice ISensitivt 1. H2S can be analyzed by coulometric titration, in which I2 is generated as part of the reaction 21 2c The generated 2 reacts with H2S L H2S So 2H 2I If 80.0 mL sample, containing excess KI, required 715 second at 125.8 mA for electrolysis to be complete, a. calculate the molar concentration of H2S (34,1 gmole) in the 80.0 mL

What is the freezing point of a solution prepared by dissolving 8g AICI, in 280 g water Assume AICI3 dissociates 100. Kewater 1.86 Cm. Molar mass of AIC13 133 gmol. OA12 C O B. 0.4 C Oc. 1.6 C O D. 1.6 C O E. 0.4 C

Write out the groundstate molecularorbital electron configurations for Na through Arz and estimate their bond orders. Which molecules among them are predicted to be unstable Which molecules are predicted to be paramagnetic

Write the two defect reactions for the solution of Nb2O5 into TiO2

3. Determine symmetry species for the SALCS required for the formation of Br Fo bonds by the 5 F atoms in BrFs (C).

a. Calculate the EMF of cells A through F at standard states (Ecell) and nonstandard states (Ecell) using Nernst equation. Fill in Table1 with your answers. ,Calculated E coell (V) Calculated Ec cell (V) Cells RT Ecell E cell InQ E E cell nF cathode anode Q is reaction quotient Zn(I)(0.1M) Fe(I)(0.1M) Zn(II)(0.1M) Pb(II)(0.1M) Zn(II)(0.1M)

1 identigy FTIR spectrum of your product and 2 Transmittance complete the HNMR and find Structure prediction table showing shift, integrations and splitting each peak labeled with associated proton(s) in structure 98 PART 2 Proton NMR of Final Product 86 90 PART 2 FTIR Spectrum of Final Product 82 80 78 76 68 66 64 H 10 3 2 3.5 8.0 7.5 7.0 6.5

Let R be the relation from N Q defined by aRb if a + 4b = 1. Prove that R is a well-defined injection from N Q.

By comparing the structure of lamivudine 1 to cytosine deoxyribonucleotide 2, explain briefly how this drug might inhibit reverse transcriptase, and how doing so can fight HIV/ AIDS. (2 marks)

NH2 NH HO H Lamivudine 1 Cytosine deoxyribonucleotide 2 Molecular Weight 229.25 LogP 1.4

Classify each of these compounds as an Arrhenius acid, an Arrhenius base, or neither. Drag each item to the appropriate bin. View Available Hint(s) Arrhenius acid Arrhenius base HNO3 HBr HC1O3 KOH LiOH Ba(OH)2 Mg(OH)2 neither NaCl CH Reset HF Help

Under conditions B, the mono-methylated product 16 is formed. What does the position of methylation tell you? Under conditions C, the decomposition product 17 is formed. Why does the change in reaction conditions (relative to A) open this alternative pathway? ?

Ph. OgAr N. 14 H A i. 2 x CHILI, 78 C ii. DO B 1.2xCHL, 78C i. 1xCHy iii. HO (workup) i. 2 x CHILI, 25 C ii. DO Ph. Ph. Ph. OgAr N. N D 15 16 0gAr N. N H 17 00 D D

The synthesis of the serum requires a reaction solution with precise control of the pH. Your responsibility for the project is to develop a buffer that maintains the pH at 6.80, the optimal level for the synthesis. In a thorough, wise, and careful essay, discuss how you will design and prepare 1.0 L of pH 6.80 buffer to test the synthetic method.

Consider the titration of a 32.0 mL sample of 0.180 molL1 HBr with 0.210 molL1 KOH. Determine each quantity: Part A the initial pH Express your answer using three decimal places. pH = Part B the volume of added base required to reach the equivalence point V = mL Part C the pH at 12.0 mLmL of added base Express your answer using three decimal

Classify each of these compounds as a BrnstedLowry acid, a BrnstedLowry base, or neither. Drag each item to the appropriate bin. View Available Hint(s) HNO2 (CH3)2NH CH3NH2 BrnstedLowry base BrnstedLowry acid HSO4 HI NH3 KBr neither CCIA Reset Help

What is the conjugate acid of C6 H5NH2 View Available Hint(s) O C6 H5NH3 C6 H5NH3 C6 H5NH3 C6 HNH O C6 H5NH C6 H5NH Submit

For the chemical equations shown below, label each reactant as either acid or base, and each product as either conjugate acid or conjugate base according to the BrnstedLowry definition. Drag each label to the appropriate target. View Available Hint(s) Reset Help conjugate acid conjugate base acid base HPO, (aq) H,0(1) H,PO, (aq) OH (aq) 4 HPO,

The following equation shows the equilibrium in an aqueous solution of ammonia NH3(aq) H2O(1) NH4 (aq) OH (aq) Which of the following represents a conjugate acidbase pair View Available Hint(s) O NH3 and H2O O NH4 and OH O H20 and OH O NH3 and OH Submit Part B What is the conjugate base of HSO3 Express your answer as a chemical formula. View

2 What is the conjugate acid of HPO3 Express your answer as a chemical formula. View Available Hint(s) B Part D Among three bases, X, Y, and Z, the strongest one is Y, and the weakest one is Z. Rank their conjugate acids, HX, HY, and HZ, in order of decreasing strength. Rank the acids from strongest to weakest. To rank items as equivalent,

What is the Ht concentration for an aqueous solution with pOH 4.27 at 25 C Express your answer to two significant figures and include the appropriate units. View Available Hint(s) H Value Units Part B Arrange the following aqueous solutions, all at 25 C, in order of decreasing acidity. Rank from most acidic to most basic. To rank items as

At a certain temperature, the pH of a neutral solution is 7.90. What is the value of K at that temperature Express your answer numerically to two significant figures. View Available Hint(s) VE K.

What is the pH of an aqueous solution with H3O 2 x 10 14 mol L1 Express the pH numerically to three significant figures. View Available Hint(s) pH Submit Part B Carbonated cola is more acidic than coffee or even orange juice because cola contains phosphoric acid. What is the molar concentration of H3O in a cola that has a pH of 3.120 Express the

Rank the following from most to least acidic. Rank from most to least acidic. To rank items as equivalent, overlap them. View Available Hint(s) Reset Help H3O 1.0 x 106 mol L 1 pH 5 pH 14 pH 3 3D H30 1.0 x 10 2 mol L Most acidic Least acidic

A new potential heart medicine, codenamed X281, is being tested by a pharmaceutical company, Pharmapill. As a research technician at Pharmapill, you are tolo that X281 is a monoprotic weak acid, but because of security concerns, the actual chemical formula must remain top secret. The company is interested in the drug Ka value because only the

0.65 g of hydrogen chloride (HCI) is dissolved in water to make 4.0L of solution. What is the pH of the resulting hydrochloric acid solution Express the pH numerically to two decimal places. View Available Hint(s) pH Submit Part B of sodium hydroxide (NaOH) pellets are dissolved in water to make 7.5 L of solution. What is the pH of this

Assuming the final solution will be diluted to 1.00 L , how much more HCl should you add to achieve the desired pH Express your answer to three significant figures and include the appropriate units. View Available Hint(s) HA Value Units Submit rovide Feedback

Y Aspirin (acetylsalicylic acid, C9 H8O4) is a weak monoprotic acid. To determine its aciddissociation constant, a student dissolved 2.00 g of aspirin in 0.600 L of water and measured the pH. What was the Ka value calculated by the student if the pH of the solution was 2.61 Express your answer numerically using two significant figures. View

What is the pH of a 0.125 mol L1 ammonia solution Express your answer numerically to two decimal places. View Available Hint(s) ...... pH Submit Part B What is the percent ionization of ammonia at this concentration Express your answer with the appropriate units. View Available Hint(s) H ..... Value Units ionization Submit

Pyridine is a weak base that is used in the manufacture of pesticides and plastic resins. It is also a component of cigarette smoke. Pyridine ionizes in water as follows C5 H5N(aq) HO(l) C5H5NH (aq) OH(aq) The pK of pyridine is 8.75. What is the pH of a 0.210 mol L solution of pyridine Express the pH numerically to two decimal places. View

Classify each salt as acidic, basic, or neutral. Drag the appropriate items to their respective bins. View Available Hint(s) Reset Help NH,Br NaCiO KCI Neutral salts Acidic salts Basic salts Submit

For the reduction of citral using Diludine as a hydride source, an equivalent of pyridine will be generated as a side-product, which you are asked to isolate and analyze. Propose a short game plan on how you could easily purify the reaction mixture for this experiment. Your plan should describe what species will be removed at each step of the

Use your averaged force constant to calculate the predicted vibrational wavenumber of the C?H and C=O stretching mode of 2?Pentanone. Use the equation editor to show your calculations. (4 marks) HH vC-H=12?c?k? = vC=O=12?c?k? =

1102 peny 105 100 96 35 4000 3600 3400 3200 3000 2800 2600 2400 Wavenumbers (cm1) 1800 1600 1400 1200 1000 BCO

i) Outline a mechanism for Step 1. ii) What is the name for the type of reaction that has occurred in Step 1?

N CI NH3 H20 N CI Step 1 N NH2 2,3dichloropyrazine Br Step 2 H heat in ethanol (solvent) CI I Br2 acetic acid (solvent) N Step 3 E Br

Using the two equations below and the provided data table, calculate the standard enthalpy of formation of H 2 S (g). 2H 2 S (g) + 3O 2 (g) 2H 2 O (l) + 2SO 2 (g) DH = - 1124 kJ/mol S (s) + O 2 (g) SO 2 (g) DH = - 296.8 kJ/mol

A fermentation process is performed using glucose (C6H12O6) as the Csource and electron donor and NO3 as the Nsource. AGcat2500 kJmol glucose. The biomass composition is CH1.800.52N0.17. a. Calculate the Gibbs free energy for biomass synthesis (YxG). b. Calculate the maximum biomass yield per electron donor (Ypmax). What is the fraction of glucose

Consider a Compton scattering event. A photon of wavelength 1.0 nm hits an atom. An electron is knocked out and a scattered photon has a wavelength of 2.0 nm. (Think of this event as a photon with wavelength 1 nm goes in and an electron and a photon of wavelength 2 nm going out.) Assuming that the electron initially had negligible kinetic and

Draw the chemical structure of the oligonucleotide 5 ACG3. Label the phosphodiester linkages the Nglycosidic linkages. Label the 5end the 3end.

What accounts for the difference between starch and cellulose A. The glycosidic bonds that connect the monosaccharides in the respective polymers B. The degree of branching in each polysaccharide C. The identity of the monosaccharides that make up each of the polymers D. A and B E. A, B and C Moving to another question will save this response.

Provide drawings of how the most bonding and the most antibonding orbitals of the system would differ in an N-methylpyridnium cation relative to those you provided for benzene. Briefly explain your answer.

Outline a mechanism for Step 1 by using curly arrow. (1 mark)

N CI NH3 H20 N CI Step 1 N NH2 2,3dichloropyrazine Br Step 2 H heat in ethanol (solvent) CI I Br2 acetic acid (solvent) N Step 3 E Br

The relative rates of increasedecrease of species in a chemical reaction are directly related to the stoichiometry. For the reaction below, which statement below is accurate 2 A 3 B C 2 D View Available Hint(s) 1 dD 1dB 2 dt 3 dt dA 1dC dt 2 dt 1 dB 1 dA 2 dt 3 dt 1 dA dC 2 dt dt Submit Previous Answers

What is the name of the compound shown here CH, CH, , Enter the name of the compound. View Available Hint(s) 23,4trimethyl1cydobutanol Submit Previos Anawers X Incorrect Try Again 5 attempts remaining

Look up the molecular structure of the polar liquid that you used, as well as the oil (oil is a mixture of many different molecules; do a bit of research and pick one molecule to represent oil), and soap (again, there is not just one molecule for soap; do some research and find a representative soap molecule). Include these molecular structures in

What is the name of the compound shown here Enter the name of the compound View Available Hints) Submat CH, CH CH, CH CHCHCH, SH

Buildings through the ages have been a significant part of the socio-economic development of civilisation. Olusola et al. (2011, p. 462) record that the first documented building collapse was that of the Tower of Babel. In the modern age, it is not uncommon to hear of building collapse as an everyday issue in various countries around the world. At

Consider the thermal decomposition of a 41.6 g calcium carbonate (CaCO, molar mass 100.1 gmol) sample in a cylinder with a movable piston CaCO3(s) CaO(s) CO2(g). View the cylinder with the compounds in it as a system. At the beginning of the process, there is no gas in the system, and the piston rests on the reactants surface. As the reaction

Write the Schdinger equation for a twodimensional hydrogen atom. Suppose that the potential is er, where r Vr y. Using separation of variables, find the radial and the angular equations. Solve the angular equation. Describe the quantum numbers that characterize the bound states and the degeneracies of the system.

Consider an electron in the 2p, orbital of the H atom a) What are the quantum numbers associated with this state b) What is the probability that the electron in this 2p, orbital will be found within the first Bohr radius from the nucleus c) Determine Lzp, and L,V2p,

a) Using your knowledge of organic reaction mechanisms, explain the formation of EACH product (A,B) in the following reaction. This will require you to write out MULTIPLE mechanisms (i.e. each product comes from a different reaction pathway). Hint all reaction pathways start from the same intermediate NaH is a strong base but cannot deprotonate an

Reverse transcriptase is an enzyme. Suggest two other biomolecular targets in HIV that can be targeted by anti-HIV/AIDS therapies. (2 marks) Briefly outline how a reverse transcriptase inhibitor exerts its medicinal effect and why this enzyme is an important target in HIV/AIDS treatment. (2 marks)

N. 1 Molecular Weight 268.24 LogP 0.05 IZ

Suggest reagents that would accomplish each of the steps (i), (iii), (v), and (x). Note that a combination of several reagents is required for some of these steps (e.g. lithium azide (LiN3) in THF, then water in step (vi)).

CH2OH ii Pb(OAc)4 iv. HCI (aqueous) CO,Et O HO H OH H2OH v. 2 TBSO TBSO TBSO vi. LIN3, THF then H20 viiix N. 1 3 N3 TBS tertbutyldimethylsilyl (Si((CH3)2C(CH3)3)) Ac acetyl (COCH3)

a) Define the term antagonist, and use your definition to explain briefly the sort of medicinal effect that a histamine H2 receptor antagonist has. (2 marks) b) Apply Lipinskis Rules to the structure of ranitidine. What does your analysis tell you about the suitability of ranitidine as a drug? (5 marks)

N. 4 NH Molecular Weight 314.14 LogP 1.23 IZ

Demonstrate your understanding of retrosynthetic analysis by redrawing step (ii) in the retrosynthetic direction to show the disconnection of compound 7 and the synthons that correspond to the two reagents. (4 marks)

i. Me,NH.HCI, CH20 ii. HS(CH2),NH2, conc. HCI N. N 0 C, 3 hours 0 C, 18 hours OH OH 7 NH2 O N

In step (i), dimethylamine (Me2NH) first combines with formaldehyde (CH2O) to form an imine (Me2N=CH2); this Mannich electrophile then reacts with 5 in an SEAr reaction. Propose a mechanism for step (i). (5 marks)

I, Me,NH.HCI, CH0 O C, 3 hours H. HS(CH),NH2, conc. HC OC, 18 hours 5 OH 6 OH NH2

By combining your understanding of both the Swern oxidation and diimide coupling reactions, propose a mechanism for the oxidation of 8 to 9 shown below. (5 marks)

DMSO HO DCC CHCO,H 9. (CH3CO2H is a source of H)

DCC is converted to dicyclohexylurea (DCU) in this reaction. Is the conversion of DCC to DCU oxidation, a reduction, or neither of these? Explain your answer.

NCN CH11 N. H DCC DMSO oxalyl chloride DCU

Apply the principles of retrosynthetic analysis to develop a synthesis of alcohol 11 from pentane-1,5-diol 12. Show all disconnections, synthons and functional group interconversions (FGI's) in the retrosynthetic direction. Suggest reagents for the forward synthesis and comment on any selectivity issues that might arise. Several steps are

OTBDMS HO COTBDMS HO HO. 10 11 12

Pyridine is a much stronger base than pyrrole (the pKa's of the conjugate acids are 5.3 and -3.8, respectively). With the aid of diagrams, explain this difference. (3 marks)

N. pyridine pyrrole ZI

Pyrrole is much more acidic than a typical secondary amine (pKa's of 16 and 40, respectively). With the aid of diagrams, explain this difference.

pyridine yrrole ZI

a) Draw a tautomeric structure for each of the nucleic acid bases thymine and guanine. (2 marks) b) The nucleic acid bases all have considerable aromatic character. Explain why this is so with respect to thymine. (2 marks)

H3C, H. HN N N. H2N N. thymine guanine Z Z

Pyridines substituted with leaving groups at the 2- or 4-position readily undergo nucleophilic aromatic substitutions. Provide a mechanism for the following reaction and explain why such substitutions do not take place at the 3-position. (5 marks)

CI SCH3 NaSCH3 N N.

Pyrroles readily undergo electrophilic aromatic substitutions, with substitution favoured at the 2-position. Provide a mechanism for the following reaction and explain why substitution is favoured at the 2-position. (5 marks)

O Z Z

Provide a reaction mechanism for the transformations below.

Provide a reaction mechanism for the transformations below.

co,CH3 NH3 CO,CH3 CI ZI

Provide a reaction mechanism for the transformations below.

NH2 co,CH 1) cat. H heat 2) POCI3 N CI

Provide a reaction mechanism for the transformations below.

HCO,C. C Co,CH3 .co,CH, NH cat. H H3CO,C. NH2 H3CO

a) Suggest a structure for the enolate (B) produced from the reaction of (A) with LDA b) Using deprotonation model diagrams, justify why this is the preferred enolate geometry.

LDA OH THF 78 C Mee 0. Me Si Me Me (B) Me Me Bu Bu Me (A) (C) recall that LDA

Using Zimmerman-Traxler transitions state models, explain why the observed C(3)C(4) stereochemistry is formed in product (C). Is this the syn or anti isomer? (10 marks)

LDA THF 78 C Meeo. Me Me Bu Me.. (B) Me Me Bu Me (A) (C) recal that LDA

a) Suggest suitable reagent(s) to perform the desired cross-coupling reaction. (1 mark) b) Although the vinyl stannane (E) is easily generated, it is not the only reagent capable of participating in the reaction. Demonstrate your knowledge of cross-coupling reactions by suggesting a plausible variant of (E) that will engage in the reaction, but

Br Bn . MeO. (D) reagents OBn O, OBn (F) OBn MeO, SnBu3 (E)