Monday
August 3, 2015

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
Sulfur trioxide decomposes into sulfur dioxide and oxygen in an equilibrium. You have a 3.00 L vessel that is charged with 0.755 mol of SO3. At equilibrium, the amount of SO3 is 0.250 mol. 2 SO3 (g) ----> 2 SO2 (g) +O2 (g) A) calculate the equilibrium concentrations of SO2 ...
Tuesday, April 28, 2015 by Ashley

Chemistry
A sample of krypton gas occupies 95.0 mL at 0.500 atm. If the temperature remained constant, what volume would the krypton occupy at (a) 5.00 atm, (b) 0.0500 atm, (c) 555 torr, (d) 5.00 torr, and (e) 5.5 3 1022 torr?
Tuesday, April 28, 2015 by Alicia

Chemistry
Determine the energy absorbed as two moles of Nitrosyl Chloride are disassociated into nitric oxide and chlorine gas (used bond energies of kJ per mole to determine your net energy released in Joules): 2NOC1(g)-->2NO(g)+C12
Tuesday, April 28, 2015 by Sam

Chemistry
Determine the energy absorbed as two moles of Nitrosyl Chloride are disassociated into nitric oxide and chlorine gas (used bond energies of kJ per mole to determine your net energy released in Joules): 2NOC1(g)-->2NO(g)+C12
Tuesday, April 28, 2015 by Sam

Food Chemistry
A new food colorant has a molar absorptivity of 3.8x 10^3 cm^-1M^-1 at 510 nm: (1) what will be the absorbance of a 2X10^-4 M solution in a 1 cm cuvette determined at 510 nm; (2) what will be the percent transmittance (T%) of the solution in (1) in this case
Tuesday, April 28, 2015 by knolan

chemistry
is the reaction between Copper sulfate and zn exothermic or endothermic and does that involve the activity series?
Tuesday, April 28, 2015 by johnny

Chemistry
A 1X Phosphate Buffered Saline solution was prepared by adding 1.44g of Na2HPO4 and 1.44g of H2PO4- to 800mL of water. Additional components were dissolved in the solution: 8g of NaCl, 0.2g of KCl and 0.24g KH2PO4. The resulting buffer solution had a pH of 7.2. a. Calculate ...
Tuesday, April 28, 2015 by Nicole

Chemistry
In a basic solution how does the concentration of H3O+ compare to concentration of OH-?
Tuesday, April 28, 2015 by Anonymous

chemistry
Lithium chlorate is decomposed with heat to give lithium chloride and oxygen gas. If 2.23g of lithium chlorate is decomposed, how many milliliters of oxygen are released at stp?
Tuesday, April 28, 2015 by kimberly

Chemistry
How does a pH of a buffer solution go outside of its range?
Tuesday, April 28, 2015 by Avery

chemistry
Calculate the approximate pH of a 0.1 M solution of ethanoic acid at 298 K, given that the dissociation constant, Ka, is 1.75 x 10-5 mol/L at 298 K.Ethanoic acid dissociates in aqueous solution as follows: CH3COOH(aq) + H2O H3O+(aq) + CH3COO-(aq)
Tuesday, April 28, 2015 by Emily

Chemistry
Cobalt and nickel can be simultaneously determined by formation of their coloured complexes with 8-quinolinol in solution. Molar extinction coefficients are: εCo = 3529, and εNi = 3228 cm-1 M-1 at 365 nm; and εCo = 428.9 and εNi = 0 cm-1 M-1 at 700 nm. ...
Tuesday, April 28, 2015 by FilthyF

analytical chemistry
What weight of potassium acid phthalate(KHC8H4O4) is required to react with 25 ml OF 0.5N NaOH solution
Tuesday, April 28, 2015 by jeslf

Chemistry
In which condition(s) can I get this reaction: Fe + H2SO4 = Fe2(SO4)3 + H2
Tuesday, April 28, 2015 by Keal

chemistry
the wavelength(nm)of a ball bearing with a mass of 10g, and a velocity of 10cm/s is what?
Tuesday, April 28, 2015 by Fernando

Chemistry
How many moles of ammonium nitrate is created from 10.7 grams of ammonium nitrate? Thus how many grams of ammonium nitrate is needed to make exactly one mole of ammonium nitrate?
Monday, April 27, 2015 by E'Manuel

Chemistry
What is the molality of a solution of aluminum nitrate that contains 77.0 g of Al(NO3)3 dissolved in 120.0 g of water? Use molar masses with at least as many significant figures as the data given.
Monday, April 27, 2015 by Heather

Chemistry
The soda was found to have a sugar concentration of 9.6% (wt./vol.). How many teaspoons of sugar are in a can of soda? (One can is 12fl.oz or 355mL) (1 teaspoon is approx. 4g)
Monday, April 27, 2015 by Carrie

Chemistry
When aqueous solutions of lead(II) ion are treated with potassium chromate solution, a bright yellow precipitate of lead(II) chromate, PbCrO4, forms. How many grams of lead chromate form when a 1.60-g sample of Pb(NO3)2 is added to 24.0 mL of 1.01 M K2CrO4 solution?
Monday, April 27, 2015 by Jamie lee

chemistry
An atom whose nucleus contains 7 neutrons and which has a mass number of 12 is an isotope of what element?
Monday, April 27, 2015 by danny

chemistry
What is the approximate effective nuclear charge for arsenic ?
Monday, April 27, 2015 by danny

chemistry
q4 What element has the greatest first ionization energy? Li Na K Rb Cs
Monday, April 27, 2015 by danny

Chemistry
How much SO2 is needed to saturate 50g of H2O at 5 degrees Celsius
Monday, April 27, 2015 by Sophia

chemistry
A 3.50L sample of neon gas has a pressure of 0.950 atm at 20 degrees C. What would the volume be if the pressure increased to 1.50 atm and the temperature remained constant?
Monday, April 27, 2015 by sun

Organic chemistry
Help with prediction products of a reaction! 4-phenylbutanoyl chloride + AlCl3 --> ? the molecular formula of the product is C10H10O, and I need to determine the product. I was thinking an acylium ion would form, and then the carbonyl carbon would form a bond with the ring ...
Monday, April 27, 2015 by anonymous

chemistry
A sample of potassium hydrogen oxalate, KHC2O4, weighing 0.717 g, was dissolved in water and titrated with 18.47 mL of an NaOH solution. Calculate the molarity of the NaOH solution.
Monday, April 27, 2015 by mary

Analytical Chemistry
Any help/advice on answering this question would be a big help! :) The analysis of lead (Pb) in a sample of solder was carried out using atomic absorption spectroscopy as follows. 1.013 g of solder was completely dissolved in a small volume of nitric acid and the solution made...
Monday, April 27, 2015 by Chris

Chemistry
Calcium hydroxide has Ksp = 5.5 x 10-5 at 25 oC and a molar mass of 74.10 g/mol. How many grams of calcium hydroxide are needed to create 365 mL of a saturated solution of calcium hydroxide at 25 oC?
Monday, April 27, 2015 by Molly

Chemistry
The radioactive nuclide 18F decays by first order kinetics with a half life of 1.83 hr. How many hours will it take for 68.5% of a give quantity of 18F to decay?
Monday, April 27, 2015 by Molly

Chemistry
20.0 mL of a 0.18 M HCl solution are combined with 50.0 mL of a 0.085 M NaOH solution. What is the pH of the resulting solution?
Monday, April 27, 2015 by Molly

chemistry
Can aluminum (Al) react with K2SO4 by single replacement to yield products? Using the activity series chart, I know that K is more reactive than Al so does that mean that a reaction will occur or not?
Monday, April 27, 2015 by Ally

chemistry
Which way will the equilibrium shift when subjected to the following changes? 2NOBr + heat <-> 2NO +Br2? NO is addded temp. doubled Br2 removed Pressure increased I said: reverse, forward, forward, forward
Monday, April 27, 2015 by Clare

Chemistry
Hi, Iodine has 53 electrons and configuration of: 2, 8, 18, 18, 7. Why does the fourth shell not reach maximum and therefore it picks up 7 electrons and begins a new shell. Thank you.
Monday, April 27, 2015 by Steph

Chemistry
A gaseous compound is 30.4% nitrogen and 69.6% oxygen by mass. A 5.25-g sample of the gas occupies a volume of 1.00 L and exerts a pressure of 1.26 atm at -4.00°C. Which of these choices is its molecular formula?
Monday, April 27, 2015 by Confuse

Chemistry
A 0.642 g sample of an unknown gas was collected over water at 25 C and 1.04 atm. The collection cylinder contained 151.3 mL of gas after the sample was released. Find the molar mass of the unknown gas?
Monday, April 27, 2015 by Anonymous

Chemistry
Samples of NH3 and 02 are placed in a rigid container. When the equilibrium below is established, the partial pressure of H2O is 0.784 atm. What is the partial erasure of NO when the system is at equilibrium? 4NH3 + 5O2 -----> 4NO + 6H2O
Monday, April 27, 2015 by Anonymous

chemistry
Suppose that a student performing this experiment recorded the concentration of NaOH solution as 0.513 M, instead of the correct value of 0.531 M. Assuming there were no other errors, would each of the following experimental results be high, low, or unaffected by the error? ...
Sunday, April 26, 2015 by kales

chemistry
please help !!! You are given an organic solid which reacts with most organic solvents. How would you obtain the IR spectrum of it?
Sunday, April 26, 2015 by katherine

Chemistry
Calculate the energy in Joules, of a photon of blue light have a frequency of 5.0 x 10^14 hertz. E=hv v=C/ƛ v= 3.00x10^8/5.0x10^14= 6x10^-7 E=(6.626x10^-34) (6x10^-7)= 3.9x10^40 Joules What am I doing wrong? I got this wrong on my exam and have a final tomorrow, so any ...
Sunday, April 26, 2015 by Stacie

chemistry
You are given an organic solution which reacts with most organic solvents. how would you obtain the IR spectrum of it?
Sunday, April 26, 2015 by Maria

chemistry
What is the pH of a 0.2 M solution of pyridinium chloride (C5H5NHCl)? Kb for pyridine (C5H5N) is 1.5 × 10−9 . 1. 8.824 2. 2.788 3. 4.761 4. 3.068 5. 3.308 6. 2.698 7. 2.938 8. 5.176 9. 9.239
Sunday, April 26, 2015 by Anonymous

chemistry
Arrange the acids I) hydrogen selenate ion (HSeO− 4 ), pKa = 1.92; II) phosphoric acid (H3PO4), pKa = 2.12; III) selenous acid (H2SeO3), pKa = 2.46; IV) phosphorous acid (H3PO3), pKa1 = 2.00; in increasing order of strengths. 1. I, III, II, IV 2. None of these 3. I, III...
Sunday, April 26, 2015 by Anonymous

chemistry
Which of the following 0.10 M aqueous solutions gives the LOWEST pH? 1. CH3COOH (pKa = 4.75) 2. CCl3COOH (pKa = 0.52) 3. HF (pKa = 3.45) 4. H3PO4 (pKa1 = 2.12) 5. Because all are acids, the pH is the same for all solutions
Sunday, April 26, 2015 by Anonymous

Chemistry
Why does AgCl dissolve in NH3 but AgBr and AgI don't? KSP of AgCl = 1.8 x 10-10 KSP of AgBr = 5.0×10–13 KSP of AgI = 1.5 x 10-16
Sunday, April 26, 2015 by Serena

chemistry
A 32.5 g sample of K2SO4 is dissolved in a quantity of water and stirred well. A 40.00 mL sample of the solution is evaporated to dryness and leaves behind 5.00 g of solid K2SO4.what is the molarity. Calculate molar masses of solutes to .01 grams
Sunday, April 26, 2015 by mark

chemistry
what products would form after hydrogenation of 2-methyl-1-butene? after halogenation (cl2)?
Sunday, April 26, 2015 by jk

AP chemistry
what products would form after hydrogenation of 2-methyl-1-butene? after halogenation (cl2)?
Sunday, April 26, 2015 by jk

pre ap chemistry
you will need to explain in detail how to make 100.0 ml of a 0.500M CUSO4.5H20(s) SOLUTION. BE SPECIFIC about the measurements you would make and the type of equipment you will use . write out steps
Sunday, April 26, 2015 by nissa

chemistry
If 5.0 mL of 0.12 mmol dm-3 MB solution is diluted by adding 20.0 mL of 0.2 mol dm-3 HCl to it, what is the new MB concentration?
Sunday, April 26, 2015 by Mara

chemistry
what products would form after hydrogenation of 2-methyl-1-butene? after halogenation (cl2)?
Sunday, April 26, 2015 by jk

Chemistry
I need help, I don't know how to approach this question The free energy generated by ion movement in the cell is used by the cell to do work. Compute the minimum number of millimoles of sodium that would be needed to pump one millimole of calcium ions if the following ...
Sunday, April 26, 2015 by Ann

Chemistry 2
Does the reaction P4(s, white) + 5 O2(g) P4O10(s) occur spontaneously at 298 K and standard state conditions? Calculate the value of capital delta S°univ. Honestly do not know where to start.
Sunday, April 26, 2015 by Anonymous

chemistry
Can anyone help me with this question. Propose a method in detail to determine the concentration of two components, quinine and anthracene in a mixture using fluorimetry. You have access to pure sulutes and an appropriate solvent. The excitation and emission spectra of quinine...
Sunday, April 26, 2015 by Briam

CHemistry
Given the following information calculate the heat of formation of C2H4. C2H4 + 3 O2 ¡æ 2 CO2 + 2 H2O ¥ÄH¡Æ = -414 kJ/mol C + O2 ¡æ CO2 ¥ÄH¡Æ = -393.5 kJ/mol H2 + ¨ö O2 ¡æ H2O ¥ÄH&...
Sunday, April 26, 2015 by sam

chemistry
Hess¡¯ law says that when we add reactions together we can also add the enthalpies. Given the following set of reactions, use Hess¡¯ Law to calculate the enthalpy of the reaction given below. N2H4 + H2 ¡æ 2 NH3 ¥ÄH¡Æ = ? ...
Sunday, April 26, 2015 by jhon

analytical chemistry
Consider a general reaction where a ligand L and a metal ion Mn+ form a complex with m number of ligands (L) coordinated to each metal ions. Assume the metal is colorless. The ligand and metal solutions were mixed at molar fractions (and same total molar concentration). The ...
Saturday, April 25, 2015 by Katy

Chemistry 2
For the gaseous reaction of carbon monoxide and chlorine to form phosgene, (COCl2), calculate each of the following. (a) Calculate S° at 298 K I got -136.76 J/K using delta S = sum of delta S of products minus sum of delta S of reactants which is the right answer. But I ...
Saturday, April 25, 2015 by Anonymous

Chemistry
Need some direction.. where do I start? Vinegar is a 5% (mass/mass) solution of acetic acid in water. If vinegar has a density of 1.06 g/mL, what is the concentration in molar?
Saturday, April 25, 2015 by Mike

CHEMISTRY
question 1.Explain why fructose and alpha-hydroxyketose reacts with benediict’s solution. what structural arrangement is necessary for the reaction to occur? question 2. When aldose react with Barfoed reagent what type of organic compound forms. What type of chemical ...
Saturday, April 25, 2015 by SHALOM

chemistry
For the following chemical reaction, how many moles of silver iodide (AgI) will be produced from 4 mol of calcium iodide (CaI2)?
Friday, April 24, 2015 by chelsea

chemistry
In a 1.00 L container at 272 degrees C 1.3 mol of N2 and 1.65 mol of H2 are added at equilibrium 0.100 mol NH3 is present calculate the equilibrium concentrations of N2 and H2 2NH3(g)<-->N2(g)+3H2(g)
Friday, April 24, 2015 by kim

Chemistry
I have water pH 7.0 insulation with various other things that do not affect pH, I am trying to add X amount of HCL to lower the solution to a pH of 1.5 I know pH=-log[HCl] but I'm not sure how to approach this problem, after this I am then trying to add NaOH to return the ...
Friday, April 24, 2015 by Margaret

Chemistry
What is name of this according to the IUPAC: a benzene that has an ethyl group on an its carbon , and a double methyl group on another carbon ? thanks
Friday, April 24, 2015 by Mad

chemistry
A mixture is made using A 50.0 mL sample of a 0.20 M aqueous solution of NAOH was added to 50.0 mL of a 0.20 M aqueous solution of HCl.What is its pH at 25.0 °C?
Friday, April 24, 2015 by aireen

chemistry
At a certain temperature, the Kp for the decomposition of H2S is 0.734.Initially, only H2S is present at a pressure of 0.102 atm in a closed container. What is the total pressure in the container at equilibrium?
Friday, April 24, 2015 by ash

chemistry
Is C2O4H- more likely to act as an acid or base
Friday, April 24, 2015 by Cortney

chemistry
If you had left your copper(II) nitrate/potassium hydroxide precipitate stand for a while, the precipitate would turn into a black powder. The copper doesn’t reduce in this reaction, but one mole of water is produced from the reaction of one mole of the copper precipitate...
Thursday, April 23, 2015 by Cortney

chemistry
If 9.00 g of _27^60 Co (half-life = 5.30 y) are allowed to decay, how many grams would be left after 1.00 y and after 10.0 y? g after 1.00 y g after 10.0 y
Thursday, April 23, 2015 by tarsa

Chemistry
Question: Describe the procedure you would follow to determine the concentration of vitamin C in a sample if the volume of DCPIP required to reach the end point were more than the 10ml graduated cylinder could hold. The titration must still be carried out in the the 10ml ...
Thursday, April 23, 2015 by Skylar Park

Chemistry
Someone help me with my titration molarity calculation please!? I have titrated 1.000 mL of Ca(IO3)2 with 2.197 ml of 0.022 M thiosulfate. First I found the moles of thiosulfate present with 0.002197 L x 0.022 M = 4.8388E-5. The mole ratio of S2O3^-2 and IO3- should be 6:1 (...
Thursday, April 23, 2015 by Mel

Chemistry
Does a k constant have a unit?
Thursday, April 23, 2015 by Marissa

chemistry - kinetics
Understanding the high-temperature behavior of nitrogen oxides is essential for controlling pollution generated in automobile engines. The decomposition of nitric oxide (NO) to N2 and O2 is second order with a rate constant of 0.0796 M−1*s−1 at 737∘C and 0....
Thursday, April 23, 2015 by Kayla

chemistry
What is the volume occupied by 0.738g of xenon gas at STP?
Thursday, April 23, 2015 by tiffany

Chemistry
A monoprotic acid of 0.065 M concentration has a pH of 2. 75. Is this a strong or weak acid?
Thursday, April 23, 2015 by Caitlin

Chemistry
The molar heat of fusion for water is 6.009 kJ/mol. How much energy would be required to melt 15.11 mol ice? Answer in units of kJ. Thanks in advance!
Thursday, April 23, 2015 by Radio Active Wear

Chemistry
The standard molar heat of vaporization for water is 40.79 kJ/mol. How much energy would be required to vaporize 8.51 ×1010 molecules of water? Answer in units of kJ. Thanks for the help!!!
Thursday, April 23, 2015 by Radio Active Wear

chemistry
15.0 mL of an iodine solution of unknown molarity was titrated against a .001 M solution of S2o32-. The blue black iodine-starch complex just disappeared when 20.2 mL of thiosulfate was added. What is the exact molarity of the Ia solution
Thursday, April 23, 2015 by chem3a

chemistry
an old tablet of vitamin c weighed 1.022 g. It was dissolved in 500 mL water, and a 25.0 mL aliquot of this solution required 22.6 mL of .005 M I2 solution to oxidize it. Calculate the mg vitamin C in the tablet.
Thursday, April 23, 2015 by chem3a

Chemistry
What is the equilibrium equation for FeS(s) + 2H3O+(aq) - Fe2+(aq) + H2S(aq) + 2H2O(l) ? Explain if possible !
Thursday, April 23, 2015 by Maria

chemistry
how to find mass of aspirin if I used 0.2845g of the powder with 1mL of 6.0 mol/L of NaOH?
Thursday, April 23, 2015 by linda

chemistry
How many milliliters of 0.748 M Mg(NO3)2 contain 1.700 g of Mg(NO3)2
Thursday, April 23, 2015 by ana

Chemistry
Determine the mass of a sample of water that absorbs 1000j of heat to melt at its melting point?
Wednesday, April 22, 2015 by E'Manuel

chemistry
How to calculate the concetration on a Beer's law plot?
Wednesday, April 22, 2015 by linda

chemistry
How many milliliters of 0.303 M NaNO2 contain 1.873 g of NaNO2?
Wednesday, April 22, 2015 by Chem3A

chemistry
How many milliliters of 0.503 M NaNO3 contain 2.528 g of NaNO3?
Wednesday, April 22, 2015 by Chem3A

chemistry
how many moles of K2SO4 are present in 111.5 mL of 0.516 M K2SO4?
Wednesday, April 22, 2015 by Chem3A

Chemistry
Consider the following reaction: CO(g)+2H2(g)⇌CH3OH(g) Kp=2.26×104 at 25 ∘C. Calculate ΔGrxn for the reaction at 25 ∘C under each of the following conditions. A) Standard Conditions B) at equilibrium C)PCH3OH= 1.3atm ; PCO=PH2= 1.2×10−2atm
Wednesday, April 22, 2015 by Ashley

Chemistry
Consider the following reaction: 2NO(g)+O2(g)→2NO2(g) Estimate ΔG∘ for this reaction at each of the following temperatures and predict whether or not the reaction will be spontaneous. (Assume that ΔH∘ and ΔS∘ do not change too much within...
Wednesday, April 22, 2015 by Ashley

Chemistry
I just need help with these three 1.Cell respiration glucose is reacted wth oxygen in body to produce carbon dioxide and water how many liters of carbon dioxide would be produced if 90.0 g of glucose completely reacts with oxygen C6H12O6(s)+ 6O2(g) -> 6H2O(g) + 6CO2 (g) 2. ...
Wednesday, April 22, 2015 by Ben

Chemistry
Can I call someone and talk to them
Wednesday, April 22, 2015 by Ben

Chemistry HW Need answers
1.Cell respiration glucose is reacted wth oxygen in body to produce carbon dioxide and water how many liters of carbon dioxide would be produced if 90.0 g of glucose completely reacts with oxygen C6H12O6(s)+ 6O2(g) -> 6H2O(g) + 6CO2 (g) How many liters of carbon dioxide ...
Wednesday, April 22, 2015 by John

chemistry
How many milliliters of a 0.250 M acetic acid solution must be added to 50.0 mL of a 0.750 M NaOH solution to produce a buffer solution with pH = 4.500 ? The pH is given by which we can calculate the concentration of [H+] How do we approach the problem from there?
Wednesday, April 22, 2015 by Anon

Chemistry
90/180.1559 =0.4995 0.4995*22.4 A. =11.2 Is this correct
Wednesday, April 22, 2015 by John

Chemistry test can't fail please help (senior)
1.Cell respiration glucose is reacted wth oxygen in body to produce carbon dioxide and water how many liters of carbon dioxide would be produced if 90.0 g of glucose completely reacts with oxygen C6H12O6(s)+ 6O2(g) -> 6H2O(g) + 6CO2 (g) How many liters of carbon dioxide ...
Wednesday, April 22, 2015 by John

Chemistry
1.Cell respiration glucose is reacted wth oxygen in body to produce carbon dioxide and water how many liters of carbon dioxide would be produced if 90.0 g of glucose completely reacts with oxygen C6H12O6(s)+ 6O2(g) -> 6H2O(g) + 6CO2 (g) How many liters of carbon dioxide ...
Wednesday, April 22, 2015 by John

Chemistry
I don't know what to do once I get the .49999 number
Wednesday, April 22, 2015 by John

Chemistry
Cell respiration glucose is reacted wth oxygen in body to produce carbon dioxide and water how many liters of carbon dioxide would be produced if 90.0 g of glucose completely reacts with oxygen C6H12O6(s)+ 6O2(g) -> 6H2O(g) + 6CO2 (g) How many liters of carbon dioxide would...
Wednesday, April 22, 2015 by John

Chemistry
One mole of N2 and 3 moles of H2 are placed in a flask at 375 degree celsius.? Calculate the total pressure of the system at equilibrium if the mole fraction of NH3 is found to be 0.21. The Kp for the reaction is 4.21 x 10 raise to -4
Wednesday, April 22, 2015 by Alex

Chemistry test help please
How many liters of chlorine as can be produced when 1.96 L of HCl react with excess O2 at STP Show Work A.0.49L B.0.98L C.1.96L D.3.92L
Wednesday, April 22, 2015 by John

Chemistry
Cell respiration glucose is reacted wth oxygen in body to produce carbon dioxide and water how many liters of carbon dioxide would be produced if 90.0 g of glucose completely reacts with oxygen C6H12O6(s)+ 6O2(g) -> 6H2O(g) + 6CO2 (g) How many liters of carbon dioxide would...
Wednesday, April 22, 2015 by John

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