Chemistry Questions and Answers May 31, 2020

A voltaic cell is created using silver (Ag / Ag + ) as one electrode and manganese (Mn / Mn 2+ ) as the other electrode. Reduction half-reaction E o (V) Ag + ( aq ) + e - Ag ( s ) 0.80 Mn 2+ ( aq ) + 2 e - Mn ( s ) -1.18 a) which metal is the anode and which is the cathode? b) write a balanced chemical equation for the redox reaction occurring

Draw the trends of graphs in case of a mixture of two strong acids Vs week base.

Sketch a graph of the expected change in the concentration of the CH200 intermediate as a function of time. 100 20 Ozonide CH200 dioxirine 2. Given that the reaction in question 1 has two rate constants, write down a fit function you would use to derive the rate constants. Explain what the terms in the equation describe. 3. Determine the

Another variation on this type of polymer is used in hair gels. In these, the polymer chains are crosslinked by a compound known as pentaerythritol. OH pentaerythritol () By what type of chemical reaction are the crosslinks in this polymer formed (H) t is important that the gel should be easily washed out of hair. What is it about the structure

List the following string electrolytes, NaCl, AICI, TICL, and CuC, in order of increasing Vant Hoff ifactors. NaCl, TICIA

Suppose the filter funnel was placed in an Erlenmeyer flask that had some residual water in it when the filtered solution of saturated Ca(OH)2 solution was collected and then a sample of that solution was pipetted into the titration beaker for one of the trials. The equivalence point volume in this titration and the calculated value of Ksp would

From the following compounds identify the bases and explain, with the aid of diagrams, why they react with acids and why the others two do not. NH2 soro CH3

The molarity of a solution is 0.15 M in NaI (aq) at 298.15 K. A large excess of HgI2 (s) to the solution. What is the solubility (in grams) of HgI2 (s) at saturation? HgI2 (s)<------->Hg2+ (aq) + 2I- (aq) Ksp= 2.7 10^-29 HgI2 (s) + 2I- <------> [HgI4]2- (aq) Kf= 0.75 M

For some compound XY (Mol wt. of XY130 gmol) at 344.94 K and 1 atm, density1.65 gcm3, 247 J(mol.K), a3.103969 and K 1.794828 atm, Find Cy (Jmol.K) for XY at 344.94 V,m Kand 1 atm. Answer

Which of these reactants will produce this product under this 3step reaction 1) Ph3P 2) NaOH Br .CI CI A) B) C) D)

Which of these is a major product if this compound is reacted in the following sequence 1. NaOCH2CH3 2. CH3I 3. Water and base 4. HCI solution and heat A) B) C) D)

Aluminum oxide melts at 2300 K, and the heat of fusion is 26 kcalmole. Assuming that the internal energy and the entropy changes that take place in going from the solid to the liquid state are independent of temperature, calculate the free energy that would be released if molten Al203 were to freeze at 1800 C (e.g., because of undercooling)

For the reaction below CHyH OH HOH a. Estimate the gas phase enthalpy change using bond dissociation enthalpies from the OWL Table Reference, not data from your text. Click the References button and then click the Tables link on the dropdown that appears. Include algebraic sign and units. b. Is the reaction exothermic or endothermic e. Is the

Provide the IUPAC name of the major product of the following reaction. pent-2-ene ---(OsO4 , H2O2) --->

What is the product and give a balanced equation?

1. H. Ni(acac)2 Ethanol HO.

Identify the ion with a +2 charge that has a ground state electronic configuration of 1s22s22p63s23p64s23d104p65s04d8. Answer with the atomic symbol or name not the charge.

A cobalt (ii) solution wants to be examined by titration with 0.0415 M EDTA solution at ph 6.0. What will be the concentrations of cobalt(ii) ions in a titration of 30.0 ml and 0.0193 M cobalt (II) solution if a)12ml b)equivalent volume, c) 16 ml EDTA is used in these titrations (K f =2.82*10^ 16 )

Sulfamic acid, HOSO,(NH,), is obtained by a complex reaction in the laboratory. CO(NH,), H,SO, SO, 2HOS0,(NH,) CO, a) From 25 g of urea, CO(NH,)2, how much is the sulfamic acid obtained when using an excess amount of other reagents b) What is the theoretical yield percentage if 61.8 g of sulfamic acid was obtained

Balance this equation for redox reactions occurring in acidic solution. MnO, As,0, Mn2 HAsO,

Complete the ionic equations and indicate whether there will be a collapse or not.

a) 2Na SO, Pb2 2NO, b) Mg2 2Ch Cu2 2NO3 c) Fe3 3NO, 2Na CO,2

Indicate whether each of the following is an oxidation reduction reaction. a) AIBr,(aq) NaOH(aq) b) Bal,(aq) Pb(NO,),(aq) c) K,SO,(aq) CuCl,(aq)

Caffeine in coffee, tea and cola is a stimulant for the central nervous system. 1.261 g pure caffeine sample contains 0.624 g C, 0.065 g H, 0.364 g N and 0.208 g O. What is the empirical formula of caffeine

Determine the electron-group arrangement, molecular shape, and ideal bond angle(s) for each of the followings: a)SO 4 2- b)NO 2 - c)PH 3 d)SO 3 e)N 2 O (N is central) f) CH 2 Cl 2

If T= - 2.5 (K- 12) log (P/ P) and T =15 k=25 P=10 then find P =?

Find P1 from the given data below: T =15 k=25 P =10 P=? T= - 2.5 (K- 12) log (P/ P)

T =15 k=25 P=10 P =? T= - 2.5 (K- 12) log (P/ P)

A silicon abrupt junction in thermal equilibrium at T = 300 K is doped such that E c EF = 0.21 eV in the n region and EF E v = 0.18 eV in the p region. ( a ) Draw the energy band diagram of the PN junction. ( b ) Determine the impurity doping concentrations in each region. ( c ) Determine V bi .

a) Positron emission tomography (PET) makes use of positron-emitting isotopes such as fluorine-18. Write a balanced nuclear reaction for the decay of F-18 by positron emission. b) An ancient skeleton has a carbon-14 decay rate of 6.84 dis/ming C. Living organisms have a carbon-14 decay rate of 15.3 dis/ming C. The half-life of C is 5715 yr. How

Fill one of your beakers to the 80 mL mark with vinegar and dissolve about 1 teaspoon of salt in the vinegar. Place the pennies in the vinegar solution. Let the pennies sit in the solution for at least one day. Place the nail or screw into the second beaker. Pour the vinegar solution from the beaker with the pennies into the beaker with the nail

Fill in the missing products in each box below. H Br Na O HO Br2 SN2 H H PPH3 H2N 1. PhMgBr 2. H30 H H20 Rxn with acetal H H2 PdC H20 only Pyridine PBr3 (Elimination)

Propose reagents and conditions for the following multistep syntheses. You may use any reagents necessary. Be sure to draw all isolable intermediates. Br.

A. Identify cach compound as Empirical or Molecular. Write your answer on the space provided. 1. Olucose (Ch0) 2. Hydmgen Peroxdde (H2O2) 3. Dichlorine Hexoxide (ClaO) 4. Buune (C.H10) 5. Fructose (CSH12O6) 6. Methyl Acetate (Call,Oa) 7. Ammonia (NH) 8. Barium Chloride (BaCla) 9. Lactic Acid (CaH6Oa) 10. Naphthalene (CsH4) ,PART B irections

Identify how many molecules for each element will be needed to form the final chemical compound. Element 1 Element 2 Element 3 Element 4 Chemical (How (How (How (How Compound many many many many atoms) atoms) atoms) atoms) Table Salt NaCl Water H20 Carbon Dioxide CO2 Caffeine C3H10N4O2 Table Sugar C12H22011

The solubility product, Ksp, for Mg(OH)2 is 8.9 x 1012 Determine the following. a. The solubility of Mg in moles per liter. Answer 1.3 x 104. b. The pH of a saturated solution of Mg(OH)2. Answer 10.4. c. The solubility of Mg in moles per liter for a pH of 11.0. Answer 8.9 x 106,

What is the theoretical phenolphthalein alkalinity of a saturated solution of Ca(OH)2

2.8 Discuss the difference between these alkalinity values (1) P and Pr, and (2) P and Mf.

One liter of solution contains 3.0 g of NaOH and 8.3 g of Na, CO3. Compute the theoretical ,values of Pr and Mf. Answer 7.7 cm 11.6 cm3.

Alkalinity tests on a mud give a P, value of 5.0 and a P, value of 0.7. Determine the ap proximate amount of undissolved lime in the mud. The volume fraction of water in the mud is 80. Answer 1.154 lbmbbl.

I A volume of 20 mL of 0.0282 N AgNO, was required to titrate 1 mL of saline water in the API test for salinity. Determine the con centration of CI and NaCI in the solution in mgL assuming only NaCl was present. Answer 20,000 and 33,000.

A 1,000mL solution contains 5.55 g of CaCI, and 4.77 g of MgCl2. a. How many milliliters of 0.02 N standard versenate solution would be required in the API titration for total hardness Answer 10 mL per 1mL sample. b. Express the concentrations of Ca2 and Mg in parts per million. Answer 5,550 and 4,770 (approximate for p,Pw).

Titrations for the total hardness of the mud and mud filtrate require 5.0 and 0.5 mL of 0.02 N versenate solution, respectively. If the volume fraction of water in the mud is 0.85, determine the equivalent free CaSO concentration in pounds per barrel. Answer 2.18.

A freshwater mud has a methylene blue capacity of 5 meq100 mL of mud. Determine the approximate sodium montmorillonite content of the mud. Answer 25 lbmbbl.

A titration test has shown that a drilling mud contains 150 mgL of calcium. The mud engineer plans to add enough SAPP (Na, H2P20,) to his 1,000bbl system to reduce the calcium concentration to 30 mgL. Determine the amount of SAPP that must be added to the mud system. Answer 116.5 lbm.

Compute the density of a mud mixed by adding 30 lbmbbl of clay and 200 lbm of API barite to 1 bbl of water. Answer 11.8 lbmgal.

Determine the density of a brine mixed by adding 150 lbm of CaCl2 to 1 bbl of water. Answer 10.7 lbmgal.

Discuss the desirable and undesirable aspects of a high mud viscosity.

Compute the yield of a clay that requires ad dition of 35 lbmbbl of clay to 1 bbl of water to raise the apparent viscosity of water to 15 cp (measured in a Fann viscometer at 600 rpm), Answer 59.3 bblton.

A mud cup is placed under one cone of a hydrocyclone unit being used to process an unweighted mud. Twenty seconds were required to collect 1 qt of ejected slurry having a density of 20 lbmgal. Compute the mass of solids and water being ejected by the cone per hour. Answer 852 lbmhr and 47.6 lbmhr.

The only available source of water for the drilling fluid has a Ca2 1 of 900 ppm and a Mg1 of 400 ppm. Determine the con centration of caustic and soda ash that would be required to remove the Ca2 and Mg2 by precipitation, Would any other undesirable ions still be present Answer 0.46 lbmbbl of NaOH and 0.84 lbmbbl of Na, CO2. Yes, NaCl.

2.23 A 1,000bbl unweighted freshwater mud system has a density of 9.5 lbmgal. What mud treatment would be required to reduce the solids content to 4 by volume The total mud volume must be maintained at 1,000 bbl and the minimum allowable mud density is 8.8 lbmgal. Answer Discard 544 bbl, add 544 bbl of water.

Name the three common causes of flocculation. Also name four types of mud additives used to control flocculation.

2.25 The density of 600 bbl of 12lbmgal mud must be increased to 14 lbmgal using API barite. One gallon of water per sack of barite will be added to maintain an acceptable mud con sistency. The final volumc is not limited. How much barite is required Answer 92,800 lbm.

2.26 The density of 800 bbl of 14lbmgal mud must be increased to 14.5 lbmgal using API barite. The total mud volume is limited to 800 bbl. Compute the volume of old mud that should be discarded and the weight of API barite required. Answer Discard 19.05 bbl, add 28,000 lbm of barite.

2.27 The density of 900 bbl of a 16lbmgal mud must be increased to 17 lbmgal. The volume fraction of lowspecificgravity solids also must be reduced from 0.055 to 0.030 by dilution with water. A final mud volume of 900 bbl is desired. Compute the volume of original mud that must be discarded and the amount of water and API barite that should be

Assuming a clay and chemical cost of 10.00bbl of mud discarded and a barium sulfate cost of 0.10lbm, compute the value of the mud discarded in Problem 2.27. If an error of 0.01 is made in determining the original volume fraction of lowspecificgravity solids in the mud, how much mud was unnecessarily discarded Answer 16.697 191 bbl.

2.29 Derive expressions for determining the amounts of barite and water that should be added to increase the density of 100 bbl of mud from e to p2. Also derive an expression for the in crease in mud volume expected upon adding the barite and the water. Assume a water require ment of I gal per sack of barite. Answer MB 109,000 (p2Pi)(28.08p2) V

2.30 A 16.5lbmgal mud is entering a centrifuge at a rate of 20 galmin along with 8.34 lbmgal of dilution water, which enters the centrifuge at a rate of 10 galmin. The density of the cen trifuge underflow is 23.8 lbmgal while the density of the overflow is 9.5 lbmgal. The mud contains 25 lbmbbl bentonite and 10 lbmbbl deflocculant. Compute the

A well is being drilled and a mud weight of 17.5 Ibmgal is predicted. Intermediate casing has just been set in 15 lbmgal freshwater mud that has a solids content of 290, a plastic viscosity of 32 cp, and a yield point of 20 lbf100 sq ft (measured What treatment is recommended upon increasing the mud weight t 17.5 lbmgal at 120 F).

A mud retort analysis of a 16lbmgal fresh water mud indicates a solids content of 32.5 and an oil content of zero. Methylene blue titrations of samples of mud, bentonite clay, and drilled solids indicates a CECm of 6 meq 100 mL, a CEC, of 75 meq100 g, and a CEC ds of 15 meq100 g. Determine (1) the total volume fraction of lowgravity solids, (2)

Define an inhibitive mud. Name three types of inhibitive waterbase muds.

Discuss why prehydrated bentonite is used in highsalinity muds.

Discuss the advantages and disadvantages of using oil muds.

Compute the osmotic pressure developed across the membrane shown in Fig. 2.36 if the saline water has a weight fraction of CaCl, of (1) 0.10, (2) 0.30, or (3) 0.44 (assume T70F). Answer 1,0003 8,500 and 22,500 psi. ,76 VAPOR WATER MOLECULE SALT MOLECULE WA ER SALINE SOLUTION 1. ME MBRANE Fig. 2.36Osmosis of water through a semipermeable membrane.

Compute the adsorptive pressure developed by a shale having an activity of 0.5 in contact with an oil mud containing emulsified fresh water (assume T70F). Answer 13.665 nsi.

Compute the pounds per barrel of CaCl, that should be added to the water phase of an oil mud to inhibit hydration of a shale having an activity of 0.8. If the oil mud will contain 30 water by volume, how much CaCl, per barrel of mud will be required Answer 98.7 lbmbbl of water and 29.6 lbmbbl of mud.

Define these terms (1) emulsifier, (2) wetting agent, (3) preferentially oil wet, (4) fatty acid soap, and (5) balanced activity mud.

A 6.125in. hole is being drilled through a 100 ft depleted gas sand. The pressure in the wellbore is 2,000 psi greater than the formation pressure of the depleted sand. The mud cake has a thickness of 0.5 in. and a coefficient of ,friction of 0.10. If the 4.75in. collars become differentially stuck over the entire sand in terval, what force would

PART A Directions Identify the common name for the following compounds. Write your anewer on the space provided before each number. 1. H20 6. HCI 2. N20 7. CaCOs 3. NaCi 8. Cao 4. CaH2(NO2)3CH3 9. NaOCI 5. (CHs)2CHOH 10. NaHCOs PART B Directions Enlist the stepe in soving empirical formula in compounds. Draw your answer on a separate sheet of

1. From the following sample solutions, identify which substance is the solute and which is the solvent. A. Instant coffee is made up of 20g powdered coffee and 100g milk. Solute: ________________ Solvent:___________ B. Vinegar is made up of 70% water and 4% acetic acid. Solute: ________________ Solvent: ______________ C. Steel is made up of 95%

Place the pennies in the vinegar solution and dissolve about 1 teaspoon of salt Let the pennies sit in the solution for at least one day Place the nail or screw into the second beaker. Pour the vinegar solution from the beaker with the pennies into the beaker with the nail or screw. Use the table of electrode potentials to explain your

Which data set would you expect to have the highest standard deviation Why Heights (lengths) of newborn infants. Heights of all elementary school children. c) Heights of firstgrade boys.

6. Write the oxidation numbers for the underlined in the following molecules, ions, and compounds 18 points a 10.1 b. Sn c. Cr(OH)3 d. CrO42 e. KCIO2 f NH3 7. Write the balanced equation for the following oxidationreduction reaction 12 points a. Mn2 Mn7 What undergoes oxidation What undergoes reduction What is the oxidizing agent What is the

Titrations 7. Calculate the pH at the equivalence point for the titration of S3 ml of 1.3 M acetic acid (K. I8s10 titrated with 22 M sodium hydroxide 8. Calculate the pH when 50 ml of 2.5 M ammonia (Ka 1.8x10) is titrated with 45 mb OF 0.9 M hydrochloric acid. 9. Calculate the pH after 60 ml of 3.0 M sodium hydroxide is added to 150 mL of 1.5M

The hydroxide ion concentration, (OH, of an aqueous solution of 0.364 M isoquinoline (a weak base with the formula CoH,N) is M.

Glycine, one of the essential amino acids, has two carbon atoms, five hydrogen atoms, two oxygen atoms, and one nitrogen atom per molecule. Its formula is written as Select one a. C2H5NO2 b. C2H5NEO2 . C22H5NO2 d. CHNO2

What is the equilibrium constant How many moles of ligand bind per mole of riboflavin binding protein 0.040 mM of riboflavin binding protein was used. Kd is 2 mM Riboflavin (ligand) mMAbsorbance 0.025 0.050 0.075 0.100 0.125 0.150 0.025 0.038 0.045 0.056 0.058 0.065

Consider the process below. The normal boiling point of CH3CN is 82 C. CH3CN(g, 103 C, 1 atm) CH3CN(I, 68 C, 1 atm) You may assume that the temperature of the surroundings is constant and also equal to 68 C. Which of the following statements about the process below isare correct Select all that apply. You may choose more than one, or none, of the

Provide a mechanism for the following transformation CrO3 H30

3.3 The oxide analysis of a cement is as follows. Weight Percent Oxide Lime (CaO or C) Silica (SiO, or S) Alumina (Al, 0, or A) Ferric oxide (Fe,Oz or F) Magnesia (MgO) Sulfur trioxide (SO3) Ignition loss 66.5 21.1 4.8 2.6 1.2 2.7 0.9 Calculate the theoretical weight fraction of CS, C2S, C3A, and C4AF present in the cement. An swer 0.666, 0.103,

3.4 List the equipment needed to perform the standard API tests for drilling cements.

3.5 Define the following minimum water content, normal water content, free water content, and maximum water content.

List the normal (API) water content of each class of cement used in slurry preparation, Answer 5.19 galsack for Classes A and B. 6.32 galsack for Class C, 4.29 galsack for Classes D through H. 4.97 galsack for Class G.

The partitioning of titratable compounds between the organic and aqueous layer can be described by the Henderson Hasselbalch Equation provided below. A pka pH lo9 HA A student in Chem 3102 has been asked to separate 2,3dinitrophenol from 4methoxyphenol shown below with pka values. The two compounds are dissolved in an immiscible organic solvent

1) Calculate the concentration of C 6 H 6 O 6 2- in an aqueous solution of 4.0410 -2 M ascorbic acid , H 2 C 6 H 6 O 6 (aq). [ C 6 H 6 O 6 2- ] = __________ M. 1b) The hydroxide ion concentration, [OH - ], of an aqueous solution of 0.358 M morphine (a weak base with the formula C 17 H 19 O 3 N) , K b = 7.410 -7 , is: [OH-]=__________M

(a) Figure 25.3 is provided below. On the axis beneath the phase diagram, plot the mixing free energy change (mix) for two cases, making sure to label each curve NKT i. T To ii. T Tc VERY IMPORTANT Make sure that you line up your two plots exactly with the phase diagram. T XAB 0 XAB 0 XAB 0 Te To Two Phases B A One Phase 3 XB B A Xe 69 (b)

How can we form the product with this starting material and a chiral auxiliary?

OH H3C H H3C CH3 CH3 H3C Ho

Lactic Acid pH find pH by approximate method and using uniroot for HA 0.1, 0.01, 0.001, 0.0001, 0.00001 make a graph of pH vs conc for both (on same graph) to compare just give me the values for graph

Combine 10 mL of acetic acid and 10 mL of sodium acetate of the same concentration to form an equal molar acetic acid-sodium acetate buffer. Split the solution into equal parts. To one half, add 1 mL increments of 0.8 M HCl until the buffer capacity is exceeded (3.57) and to the other half add 1 mL increments of 0.8 M NaOH until the buffer

A gas behaves ideally and its C, is given by CoJ K mol 44.22 8.79 x 10 TK8.62 x 105 T K If I mole of this gas is heated from 300 K to 1000 K at constant volume The enthalpy change (AH) is Select one O a 30.95 kJ Ob 3294 kJ Oc 803 kJ Od 603 kJ Oe 44 22 kJ

The following Kekule structure is that of an essential component of nucleic acid. Determine its molecular formula. Enter your formula with the notation, C#H#O#.

1. For H 2 + , Using a minimal LCAO wave function, we explored three important integrals, J, K, and S. Draw each as a function of bond length (J(R), K(R), S(R)), and a briefly describe what the physical significance of J, K and S is. A single sentence or a mathematical expression is sufficient for each. (Simply giving them a name is not sufficient

(ba) 28. Why world isomorphos sabetihation exit between caleiui and sediim ims buat nat between potas mm and aluminum ims.

If the objective is to obtain metallic silver, what would be the mineral from which it can be obtained? If other metals are present, how are they separated? And under what method can it finally be obtained? (Is it possible to apply the same as for copper?).

The reaction of HCl with NaOH is represented by the equation HCl + NaOH =NaCl+H2O what volume of 0,614M HCl is required to titrate 18,8mL of 0,619M NaOH?

A chemistry graduate student is given 300. mL of a 0.20M hydrocyanic acid (HCN) solution. Hydrocyanic acid is a weak acid with K. 4.9 x 10 10 What mass of KCN should the student dissolve in the HCN solution to turn it into a buffer with pH 9.11 You may assume that the volume of the solution doesnt change when the KCN is dissolved in it. Be sure

A chemistry graduate student is given 300. mL of a 0.20M hydrocyanic acid (HCN) solution. Hydrocyanic acid is a weak acid with K. 4.9 x 10 10 What mass of KCN should the student dissolve in the HCN solution to turn it into a buffer with pH 9.11 You may assume that the volume of the solution doesnt change when the KCN is dissolved in it. Be sure

Use the angular overlap model, calculate the orbital energies (-donor) for trigonal pyramidal (TP). (z2 ; x2-y2 ; xy ; xz ; yz, respectively )

What volume of 0.200M HCl must be added to 500.0 mL of 0.300M sodium mandelate to produce a buffer solution with a pH of 3.37?

What are the J-coupling splitting patterns expected in 11 B ( I = 3/2), 1 H ( I = 1/2), and 2 H ( I = 1) NMR spectra for a tetrahedral anion, [ 11 BDH 3 ] , if the relevant J-coupling constants are 1 J( 1 H, 11 B) = 65 Hz, 1 J( 2 D, 11 B) = 15 Hz, and 2 J( 1 H, 2 D) = 7 Hz. What are the spectral line positions in Hertz and relative peak

How much 5,70 MNAOH must be added to 450.0 ml of a bulfer that is 0.0195 Macetic acid and 0.0275 M sodium acetate to raise the pH to 5.75 mL