Chemistry Questions and Answers May 15, 2020

Propose a sequence of steps to perform the following transformation

OH

Bonus Propose a mechanism Must be perfect for any points NaOEt OEt EtO EtO HOE

Calculate the final temperature of a mixture of 180.0 g of ice initially at -13.00 C and 355.0 g of water initially at 86.50 C

1. Sucrose has two components, glucose and fructose. You have a special oxidizing agent, which... will oxidize all 1 alcohol(s) to one of the two possible products, might or might not oxidize any other alcohol groups, and will make a product with at least 3 different oxygencontaining functional groups. Choose either glucose OR fructose, in its

What is the Huckel Hamiltonian for a 1,3 transbutadiene molecule?

Which for the following are always true for a spontaneous process (Choose all correct answers) OEnthalpy of the universe increases Enthalpy of the surroundings increases Entropy of the surroundings increases OEntropy of the universe increases L Entropy of the system increases Enthalpy of the system decreases

An aluminum cube with a mass of 25.0 g and an initial temperature of 75 C is put into 100.0 g of water with an initial temperature of 25.0 C. What can you conclude about the final temperature once the aluminum and water come into thermal equilibrium (Assume no loss of heat to the surroundings.) O The final temperature will be between 50 C and 75

Q4 The cyclopropenyl radical has three carbon atoms situated at the corners of an equilateral triangle. Molecular orbitals for the relectrons can be approximated by linear combinations of the 2p, orbitals of the carbon atoms. Determine the eigenvalues and eigenfunctions for the radical in the Hckel approximation and find the total energy of the

A polymermatrix composite (PMC) is made with a matrix of polyester reinforced with 45 vol of Eglass. Given the elastic moduli for for polyester and Eglass are 6.9 GPa and 72.4 GPa respectively. Determine the modulus of elasticity of the composite in the transverse direction.

(a) CH3CH2 OH 10C

(a) CH3CH2 OH 10C

Draw the mechanism for nitration of phenylacetic acid. Include formation of the electrophile. The mechanism should explain why the product is ortho, para, or meta. List 2 additional meta directors, List 2 additional ortho , para directors.

Which term best describes the isomeric relationship between the following pairs of sugars (structures can be found in Fig. 7.2 and 7.3) Choices include the following not isomers, constitutional isomers, enantiomers, diastereomers, epimers, or anomers. a. Dsorbose and Dpsicose b. Derythrose and Darabinose C. Dsorbose and Dfructose d. Dgalactose and

As part of the Compounds of Copper experiment, copper(II) carbonate is acidified with hydrochloric acid to form a copper(I) chloride solution. The copper (II) chloride is then allowed to react with aluminium metal to form copper metal which is finally recovered by filtration. If the filtrate from the final filtration appears clear and greenish in

The structure of doxorubicin is shown below. This anticancer drug interacts with DNA to prevent replication and halt cancer cell division. The two essential features for the drug to exert its effect are the tricyclic ring system (highlighted in blue) and the protonated amine (highlighted in red). a. Predict how the tricyclic ring system would

a. Draw all products formed, along with any resonance structures, side products, and a curved arrow mechanism. b. At equilibrium is there more starting material or product Why Explain your answer with structures andor pka values NaOEt Et 17 FO

An aqueous solution is 3.50 by mass hydrochloric acid, HCI, and has a density of 1.02 gmL. The mole fraction of hydrochloric acid in the solution is ,1. Draw the structure of Sangers DNA sequencing agent ddGTP (dd is dideoxy) at pH 7.4 (9 points). Please show correct ionization states.

Which of the following are false concerning the hybridization of atomic orbitais and bonding found in carbon structures O It accounts for the number of sigma bonds found in carbon structures. O More than one of these. Oit explains why carbon forms four bonds instead of two bonds with two lone pairs of electrons on carbon. Ot would not violate the

Identify the molecule represented by the Mass Spectrum below. MASS SPECTRUM 100 80 60 40 20 0.0 30 60 45 mz Rel. Intensity 0.0 2iodopropane 2fluoropropane 2chloropropane 2bromopropane 15 75 90

What is the product of the following reaction NaOCH3 CHOH OH OH IV

79 The following molecular parameters describe the rotational energy level structure of methyl bromide (H3 CBr) A 5.22822 cm1 D, 3.29 x 107 cm1 B 0.31686 cm1 DJK 4.29 x 106 cm1 79 a) Is H3 CBr a prolate or an oblate top Explain your reasoning. 79 b) Calculate the 00 10 transition for H3 C Br in wavenumber. c) Draw and label an energy level

The following reaction is key when investigating the precipitation and dissolution of AB2CO3 Ag, CO (s) 2 Ag (aq) Co (ag)K 8.5 x 10 12 If we were to mix 0.00110 mol of solid A82CO3 in 2.00 L of pure water, how much solid would be left at the end Do not make an approximation calculate the exact value. Submit your answer in moles with 5 decimal

Fill in the missing product with pr oper stereochemistry or the missing reagents on thearrow for the foll owi ng reacti ons. B 1. NANH, 2. .CI H2, Lindars xs Ch 1. Sia, BH, THF 2. ,,, Catalyst E C 1) O3 2) DMS F

Which action would NOT cause reaction rate increase adding product increasing temperature adding reactant Operforming reaction in solution rather than solid state

10) Suppressor columns in ion chromatography are used to a) Enhance ionic strength in mobile phase b) Remove ions that interfere with the detector signal c) Derivatize ions for better detection d) Protect the detector from chemical corrosion e) None of the above

1. What is the M 2. What is the mz of the base peak 3. Does it contain chlorine Explain your answer. 100 MASS SPECTRUM 80 60 40 20 0.0 10 20 30 40 mz NIST Chemistry WebBook (httpswebbook.nist.govchemistry) Rel. Intensity 50 60

Consider the ion He 2 2+? (charge on each nucleus A or B is Z=2). a) Using the diagram above write down the Hamiltonian for the He22+ ion explicitly including all kinetic energy and potential energy terms (Hint: it may be easier to work in atomic units) b) He 2 2+ is a multielectron molecular ion and, therefore, the wave function has to account

TAl A rei R P12 2 B 182

Provide the structure(s) of the expected major organic product from the following reaction 1) Disiamylborane CH,CH,C(CH,),C CH 2) H2O2, NaOH Edit

Outline a synthesis of cyclopentene from each of the following: a-bromocyclopentan b- 1,2dichlorocyclopentanol c-cyclopentanol

Saccharin is an artificial sweetener that is used in diet beverages. In order for it to be metabolized by the body, it must pass into cells. Below are shown the two forms of saccharin. Saccharin has a pkb of 12.69. If you drink a beverage that is sweetened with saccharin, as the saccharin passes through your digestive system, where in your body

Vanillin is the major substance in vanilla, which is used in making many sweet baked foods. Vanillin is a weak acid with pka of 7.4. When making chocolate chp cookies (see picture recipe), vanilla is added at step 2 in the recipe. At this point, the butter and sugar mixture has a pH of about 6.3. What is the percentage of the base form of vanillin

One day during the pandemic, you decide to do a home experiment. You find some tetracycline in your medicine cabinet and you crush up a tablet of it and add it to barely enough water until it dissolves. Then separately, you get some orange juice from your refrigerator (which has a pH of 3.5). After the orange juice is at room temperature, you add

The acid that is most responsible for the acidity of lemonade is citric acid, whose pka is 2.79. The pH of lemonade is 2.0. What is the percent ionization of citric acid in lemon juice 86.0 A. 83.8 OB. 14.0 C. 16.2

n

Part of the speciation graph of a commonly used red food dye is shown below. The molecular structures of both species whose concentrations are graphed are also given below as species 1 and species 2. Identify which species corresponds to which line and what is the value of pka. Red food dye speciation at different pH values Species 100 90 80 70

The molecule shown is a medicine that is currently under study in clinical trials for treating ADHD. This molecule has both acidic and basic properties. In this molecule, site base is most stabilized due to being on the delacalized by resonance. In this molecule, site is the location of the proton (Ht) that is most acidic. This proton is most

Consider the following transformation in which two of the carbon atoms change oxidation state. In order to be an oxidation or reduction, both carbons that are changing must change in the same direction. Is this transformation an oxidation, a reduction, or neither H2C CH2 cH H C H H neither A. oxidation . there is not enough information to tell

The molecular structure shown below has only carbon, hydrogen, and oxygen atoms in it. Its molecular formula is CgHgO. 2 HO 1 What are the oxidation states of the carbon atoms labeled 1 and 2 OSC 1) 1, OS(C 2) 1 OA. OSC 1) 1, OS(C 2) 1 B. OC. OS(C 1) 1, OSC 2) 1 OD. OSCC 1) 1, OS(C 2) 1

The oxidation states of all atoms are shown with the balanced chemical equation 1 2 1 2 (1 (1 1 2 1 Cu 2 CH4 (g) 2 H202(1)CHCH,OH(I) 3 H20(1) (1 4 1 1 4 1 3 (1) 2 1 (1 For this reaction, determine which element is reduced and which species is the oxidizing agent. OA Cis reduced, H202 is the oxidizing agent C is reduced, CH4 is the oxidizing

Consider the following three reactions Reaction 1 2 Fe(s) 3 O2(g) 2 Fe2Og(s) Reaction 2 CO2(g) H2(g) CO(g) H2O(g) Reaction 3 H2COOH(aq) CHGNH2(g) CH3NH3 (aq) H2CO0 (aq) Identify what type of reaction each one is. Reactions 1 and 2 are redox reactions. Reaction 3 is an acidbase reaction. Reaction 1 is a redox reaction. Reactions 2 and 3 are

Eugenol is the primary component in cloves (a spice). Eugenol gives ketchup its distinctive flavor, it is the odor of clove cigarettes, and both the taste and the odor are evident when cloves are steeped in hot water to make clove tea. Eugenol is a weak acid with pka 10.2. The acid ionization reaction of eugenol is HO. H,0 H30 eugenol The

Which is(are) the LCAO(s) of the third energy level for four atoms A, B, C, and D in a square planar geometry with A and C on the x axis, and B and D on the y axis The answer you get here may be used for another question. O (4A We) and (4c 4o) (WA Wc) and (Wg Yp) O (YA 4) (4a Wp) and (4A Y) (4c 4b) O WA WB4c 4D O WA WB 4c 4D

Given the average and standard deviation of the diffusion coefficient of ferrocene, 2.24(0.07) x 105 cm2s N 10. What is the 95 confidence interval, input as if it was that number not as a range. Note Your answer is assumed to be reduced to the highest power possible. Your Answer x10 Answer

4. Identify reagents in the following scheme Br Br OH

5. How would you carry out the following conversions More than 1 step may be needed in some cases. CI RCHCH3 a RCH2CH2OH R e R

1. Provide a mechanism for the following transformations. What are the similarities and differences between the two reactions Br. Br2 H20 Br, Br2 H20

2. Predict the product of the following reaction H2 PdC H2 Lindlars catalyst

I ne hydrolysis of esters in base is called transesterification. the Fischer esterification. saponification. the Hunsdiecker reaction. the Dieckmann condensation. Predict the product of the following reaction. O 1. NaOCH 3 2. evo 04 OH FO H3O A

Which of these instruments can be used for quantitative determination of benzoic acid in soft drinks i. Thermo Scientific Genesys 20 Single Beam Spectrometer ii. Agilent Cary Eclipse Fluorescence Spectrometer iii. Agilent Cary 100 UVVis Spectrometer iv. PerkinElmer AAnalyst 200 Double Beam Atomic Absorption Spectrometer v. PerkinElmer PinAAcle

6. Provide a synthetic strategy for the following transformations.

7. When propyne is basified with sodium amide, the resulting akynyl anion can undergo nucleophilic addition to an aldehyde like ethanal (CHCHO). Propose a reasonable mechanism for the previous description and predict the product of the reaction.

After Larry had taken Nexium for 4 weeks, the pH in his stomach was raised to 4.57. What is the H3O in his stomach Express the concentration to two significant figures and include the appropriate units. HA HO) Value Units Submit Previous Answers Request Answer X Incorrect Try Again

Ethylene oxide (EO) is prepared by the vaporphase oxidation of ethylene. Its main uses are in the preparation of the antifreeze ethylene glycol and in the production of poly(ethylene terephthalate), which is used to make beverage bottles and fibers. Pure EO vapor can decompose explosively H,CCH2(g) CH(g) CO(g) Liquid EO has AH 77.4 kJmol and AH

Indicate the use of sodium bicarbonate in the process of chloride synthesis of t-pentyl.

Consider an ionic compound, MX,, composed of generic metal M and generic gaseous halogen X. The enthalpy of formation of MX, is AH 797 kJmol. The enthalpy of sublimation of M is A Hub 171 kJmol. The first, second, and third ionization energies of M are IE, 565 kJmol, IE 1665 kJmol, and IE3 2527 kJmol. The electron affinity of X is AHEA

?

Use the taut string construction given in Figure 10.7 to sketch a plot of the chemical potential of component 2 as a function of composition for this system.,AG mix 0 0 a B IL ILI W I F 1 X FIGURE 10.7 Taut string construction shows the sequence of equilibrium conditions across the composition range in a system that may exhibit four different

?Find the heat of combustion of Cyclopentane C5H10. My given heat of formation was (-76.4) according to my data I got Heat of Combustion = 3472.9 KJ/mol. ?Find delta H, Delta S, and delta G at 298Kelvin. ( the image refers to my work on how I got heat of combustion )

pys 2 (SC 2 H 1 (H10) 10 (C02 (02) flipped 10 (M 1202 H0) 10 (285.8 K101) mol Cyclopentane C5H0 10C 4H15 10 (02 10H12 502 10120 2251110 100 100 100 HF 16.9 Rimol 11 (393.5 KS) 6945.8 2 t HC 3972.9 5J K mal 2 (76.4) 10 (393.5) 10(285.8) 2C5H10 150 10 C0 10 10

out of each product from A,B, C,D which one is 1. most stable product 2. least stable product 3. could exist as an E/Z 4. draw the E version of that compound 5. draw the Z version of that compound

H2OHIA nso (B) (CH3)CC(CH3)(CH2)2CH3 xon A . (A) C(CH3)2(CH2)4CI (C) CCH2 (D) C(CH3)2CH(CH2)2CHCH2 CH(CH3)(CH2)2CH3

Draw the curved arrows that accomplish the following transformation. Be sure to include lone pairs where needed. Label each step of your mechanism as nucleophilic attack (NA), loss of leaving group (LLG), proton transfer (PT), or rearrangement (R). HO

1In a 100 ml beaker, place ethyl acetoacetate (4mL) and cool in ice bath. 2To the ethyl acetoacetate hydrate (2 mL) was added dropwisely with stirring 3 Leave in the ice bath for an additional 10 minutes where a white ppt is formed. 4 Filter the product on suction and wash it thoroughly with petroleum ether (5 ml) to remove unreacted ethyl

(2) Why are Sixmembered rings more favorable than other ring. (2) Why does the chair confirmation have the lowest energy for Cyclo hexane (3) For the molecule OH H H Br Z Hs Per form a ring Flip in a Determine which one has the lower energy

Complete 1H NMR spectrum H. H Br H H Br H Assign each proton in the structure above a signal (A,B, C) C. B.

To grow the soil bacteria, CardenasEspinosa et al used the base mineral media described in Table 1.1. Table 1.1. Base Mineral Media Compound Mass needed for 1 Liter 7.0 g 2.8 g 0.5 g 0.1 g 0.1g 10 mg 5 mg 6.4 mg 1 mg 0.6 mg 0.36 mg 0.36 mg 6.5 mg 10 mg 37 (mv) HCI 146 L Microplastics in the ocean is a significant problem and would require bacteria

The common ion effect is used to make the analytical reactions more quantitative. a. True b. False

Write the complete mechanism for compound x & y. y is an alcohol. Show all steps.

NeOES, ETOH Compound x Campand Y Ehe wite the toplete mchenism dor conpound x t Y. Yis on olahal Show all stps Y

A liquidliquid extraction process conducted in Electrochemical Materials Laboratory involved the extraction of nickel from the aqueous phase into an organic phase. A typical set of experimental data from the laboratory is given below. Ni aqueous phase 2.00 2.50 3.00 a (gl) Ni organic phase 8.57 10.0 12.0 g (gl) Assuming g is the amount of Ni in

Using the following diagram, explain how the chemical potential determines the fusion and boiling temperatures of a substance. Solid Liquid Gas Solid stable Liquid Gas stable stable T, Temperature, T T. Chemical potential, u

A glass pH electrode produced a response according to Equation 156. (a) Suppose 31.00 and the outside of the electrode is immersed in a pH 1.00 solution. If a voltage of 50.21 mV is produced at 25C, then what is the value of the constant in the equation mV (b) Assume the constant is the same as in (a) but the solution pH on the outside of this

Which of the following must be overcome during the boiling of PF3 Make sure to draw a Lewis structure first (2) dipoledipole forces (3) hydrogen bonds (1) dispersion forces 1 only 2 only 1 and 2 1 and 3 1, 2, and 3

For the following reaction, which is the correct mechanism for the ADDITION of the acetylide ion across the carbonyl group (CO) 1) H H. OH HCECCH 2) H,0 mild H0H OH HCECe HCECCH H HCECCH H0H H HCECCH HCEC0. HCECCH b) H. H HCECO HCECCH H. HCECCH HCEC0 HCEC(H HHCECCH d) OH HCECO HCEC 6 HCCC

Why do some water insects able to walk on water? Explain

Explain how adhesion and cohesion help plants move materials

When is water the densest?

Explain why ice floats.

What is the slope of the tangent drawn to the net force curve at equilibrium distance Ltfen birini sein a Cohesive force b. Modulus of elasticity c Bond energy d. Cohesive strength

7. (11 pts) Show how you would accomplish the following synthesis. You can use any reagents and solvents.

b Write a mechanism for the step shown below, using curved arrows to show electron redistribution. Arrowpushing Instructions CHCH OCH,CH3 H H OCH,CH,

How many grams of 100C water can change to 100C steam if 32,540J of heat is added?

If a sample containing NO3reduces the ringdown time from 10.0s (empty cavity) to 8.5s, what is the concentration (molecules cm-3) of NO3 ?

Use Table 6 values to calculate AG (in kJ) at 2000 K for the following reaction NO2 (g) CO(g) NO(g) CO2 (g) O 990 kJ O199 kJ 420 kJ O1211 kJ O 222 kJ

Give iupac name of this compound

CH3 CH2CCHCHy0P0P0

12.12(a) Estimate the centrifugal distortion constant for H1271, for which B 6.511 cm and v 2308 cm. By what factor would the constant change when H is substituted for H

If the wavenumber of the J = 32 rotational transition of 1 H 35 Clconsidered as a rigid rotator is 63.56 cm 1 , what is (a) the moment of inertia of the molecule, (b) the bond length?

The following monomer can be used for the synthesis of- n

Use the data given below to construct a BornHaber cycle to determine the lattice energy of Cao. DH (k) Ca(s) Calg) (3),) (3)e Ca e) Ca2e) e Ozle) 20g) O) e Oe) O) e 02 () Ca(s) 12 02e) CaO(0) 193 Sublimation 590 First ionization energy 1010 Second Ionization 498 Bond Energy First electron affinity Second electron affinity Enthalpy of

give the organic products to the reactions, with the correct stereo- or regio- chemistry

CH3 H30 C,H5CO3H CH3

A 35.0 mL solution of a Co2 with concentration 0.20 M is titrated with a 0.10 M EDTA solution buffered at pH9. Find the pCo2 after adding the following volumes of titrant a)Vadded 20.0 mL, b)Vadded 70.0 mL, c)Vadded 80.0 mL. log Kf (COEDTA)2.81x 1016

4) Propane burns in oxygen to form water and carbon dioxide according to the following balanced equation. Assuming all heat comes from this reaction, a) what mass of propane must be burned to provide 1.3 x 10 J b) What mass would be needed if the heat transfer process was only 60 efficient C3HS ()5 O2 (8) 3 CO2 (8) 4 H2O () (8) AH 2,221 kJ 3D

Which of the following amounts of solute, dissolved in 1.0 kg of water, creates a solution with the highest freezing temperature (assuming ideal behavior) O a. 0.0015 mol of sulfuric acd, H 2SO 4 b. 0.0015 mol of H 2SO 3 O . 0.0015 mol of sucrose, C 12H 220 11 O d. 0.0030 mol of methanol. CH 3OH O e. 0.0030 mol of ethanol, CH 5OH

complete the following for BrF3, SF4, IF4+, SO3-2, XeF2, and SF2: - lewis structure drawing - bonding electrons - nonbonding electrons - hybridization - AXE notation - molecular geometry - polar or nonpolar - resonance - isomers - wedge and dash drawing

4. Please try to plot the band structure of Mg (Ne3s), Ga(Ar3d 4s 4p), trying to explain why they would form this type of band structure

A substance has an enthalpy of vaporization of 22.89 kJ mol1. If the vapor pressure is 0.153 bar at 14.83 C, what is the temperature when the vapor pressure is 1.000 bar?

what reactions can be identified within the synthesis of cephalexin?

Step 1. Bromine substitution of isobutyl alcohol This reaction is analogous to the one you did in Week 78. However, in this one you obtain two constitutional isomers of the product, and you will need to separate them in order to move on to the next Postlab questions synthetic step. Once youve carried out the purification, you isolate 29.6 grams of

Step 1. Bromine substitution of isobutyl alcohol This reaction is analogous to the one you did in Week 78. However, in this one you obtain two constitutional isomers of the product, and you will need to separate them in order to move on to the next synthetic step. Once youve carried out the purification, you isolate 29.6 grams of

Step 1. Bromine substitution of isobutyl alcohol This reaction is analogous to the one you did in Week 78. However, in this one you obtain two constitutional isomers of the product, and you will need to separate them in order to move on to the next Postlab questions synthetic step. Once youve carried out the purification, you isolate 29.6 grams of

The elemental analysis of an unknown compound gives the following results: 74.99 % C, 5.034 % H, 19.98 % O. What is the empirical formula of the unknown compound

Place the best reagent in the bin for each of these reactions involving cyclohexylmethanol. Br Answer Bank HBr NaBr NaCI NaH PCC SOCI, MCPBA OH H,SO, CHI 2. PBr HCI Cro, H,0 CI H.

Palymrs Proctice O BuLi cosCH3

Find the lifetime of NO2 at night at altitudes z 0, 5, 10 km. M 2.5 x 1019 1.3 x 1019 0.65 x 1019 z km TK 288 256 10 223 NO, O NO3 O2 Assume an O, mixing ratio of 50 ppb and k 1.2 x 1013 exp (2450T) cm molecule s