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December 19, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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Chemistry
HW Help!!!! An object at 4500 K emits the blackbody spectrum shown here. This object emits the most light in the __?__ part of the visible spectrum.
Monday, December 1, 2014 at 1:04am

Chemistry
The color of light emitted by a hot solid object depends on?
Monday, December 1, 2014 at 1:02am

Chemistry
Given the following equation: N2 (g) + 3H2 (g) → 2NH3 (g) ΔH = -92.6 kJ Calculate ΔH (in kJ) for the decomposition of 30.5 g NH3 (g) into N2 (g) and H2 (g)
Monday, December 1, 2014 at 1:00am

chemistry
write the specific heat water and liquid and gas
Monday, December 1, 2014 at 12:22am

Chemistry 2
In a particular redox reaction, MnO2 is oxidized to MnO4– and Ag is reduced to Ag. Complete and balance the equation for this reaction in acidic solution. Phases are optional.
Monday, December 1, 2014 at 12:10am

chemistry
chemical reactions type?
Sunday, November 30, 2014 at 11:16pm

Chemistry
1. Suppose that you have 0.500 L of each of the following solutions, and an unlimited supply of water. (Note: C9H7NHBr is a salt containing the ions C9H7NH+ and Br− and C9H7N is quinoline, an organic base with pKb = 6.24 at 298 K. If you like, you may represent C9H7NH+ ...
Sunday, November 30, 2014 at 11:10pm

chemistry
Sodium vapor lamps are used in Chicago to light city streets. The light emitted (given off) by these lamps has a λ of 5.9 x 10-7 m. What is the λ in cm? What is the λ in nanometers (nm) [1 meter = 1 x 109 nm]? What is the ν of this radiation? In what region...
Sunday, November 30, 2014 at 10:03pm

Chemistry
I need chemistry help. I think 1. c, 2.b, & 3.a (please tell me why or why not and help me set up the problems if possible) 1.) The following half reaction has been balanced except for the electrons. How many and where should the electrons be included? 14 H+(aq) + Cr2O72-(aq...
Sunday, November 30, 2014 at 9:10pm

Chemistry
5.) Which of the following is the strongest oxidizing agent? a.) Zn(s) b.) Mg(s) c.) Al3+(aq) d.) Mg2+(aq)
Sunday, November 30, 2014 at 9:06pm

chemistry-chemical equations
How do I write the balanced chemical equation for Copper +nitric acid -> copper(II)nitrate+ nitrogen dioxide + water
Sunday, November 30, 2014 at 8:48pm

Chemistry
To 1.0 ml of 1.5%NaCl, water is added to a final volume of 100ml. What is the molarity NaCl of this final solution? 1.5g/100ml I do not know where to go from here?
Sunday, November 30, 2014 at 8:45pm

chemistry
If you place 10.0 L of propanol (C3H8O) in a sealed room that is 3 m long, 2.75 m wide, and 2.5 m high, will all the propanol evaporate? If some liquid remains, how much will there be? The vapor pressure of propanol is 10.7 torr at 25 °C, and the density of the liquid at ...
Sunday, November 30, 2014 at 8:35pm

Chemistry
I'm looking for a video of a chemical reaction that can help me answer these questions What are the names of the reactants and products and their states @ room temperature? What type of reaction is it?
Sunday, November 30, 2014 at 8:32pm

Chemistry
Bromine has two naturally occurring isotopes, the first of which is 79Br with a mass of 78.904 amu and an abundance of 50.54%. Calculate the mass of the other isotope.
Sunday, November 30, 2014 at 8:12pm

Chemistry (Titrations)
In order to standardize a KMnO4 solution, 0.2848 g Fe(NH4)2(SO4)2·6H2O was dissolved in 25 mL 0.18 M H2SO4. The KMnO4 solution was added to the Fe(NH4)2(SO4)2·6H2O solution until a pale pink color persisted. The titration took 24.2 mL of KMnO4 solution. What is ...
Sunday, November 30, 2014 at 8:06pm

Chemistry
What volume of H2 gas (in liters), measured at 23 °C and 678 torr, can be obtained by reacting 7.59 g of zinc metal with 124 mL of 0.302 M HCl? Zn + 2HCl --> ZnCl2 + H2
Sunday, November 30, 2014 at 7:46pm

CHEMISTRY HELP
what are the diff b/in: 12. Dilute to and dilute with 13. Warm, boil 14. Heat almost to boiling 15. Heat just to boiling 16. Evaporate to 17. Evaporate to almost dryness 18. Concentrate the volume to 12. I know the meaning of dilute its reducing the concentration but idk ...
Sunday, November 30, 2014 at 7:39pm

chemistry
A 0.205 g sample of impure NaOH requires 17.5 mL of 0.2180 M HCl for neutralization. What is the percent of NaOH in the sample, by weight?
Sunday, November 30, 2014 at 7:31pm

Chemistry Correction
Hi, I'm trying to solve for the radius of the sphere. This is the correct steps: 8.27*10^-29 = 4/3 pi * r^3 r^3 = 2.0225 * 10^-29 cu meters When I do 8.27x10^-29 / 4/3 pi, I don't get the answer 2.0225x10^-29 Can you tell me what I'm doing wrong?
Sunday, November 30, 2014 at 7:28pm

chemistry
Determine how many milliliters of 0.310 M HClO4 will be required to neutralize 52.37g Ca(OH)2 according to the reaction: 2HClO4 + Ca(OH)2 ---> Ca(ClO4)2 + 2 H2O
Sunday, November 30, 2014 at 7:02pm

Chemistry
Consider the reaction for the production of NO2 from NO: 2 NO(g) + O2(g) = 2 NO2(g) a)If 84.8L of O2(g), measured at 35 degrees Celsius and 632mm Hg, is allowed to react with 158.2g of NO, find the limiting reagent. b) If 97.3L of NO2 forms, measured at 35 degrees Celsius and ...
Sunday, November 30, 2014 at 6:58pm

Chemistry
The addition of a crystal of sodium chlorate to a sodium chlorate solution containing no undissolved solute causes additional crystals of sodium chlorate to precipitate. The original solution was supersaturated or unsaturated
Sunday, November 30, 2014 at 12:20pm

Chemistry
how many grams of ammonium nitrate would you have to add to 25mL of room temperature water to get 36°F?
Sunday, November 30, 2014 at 1:20am

Chemistry
A) if you added 8g of ammonium nitrate to 25mL of room temperature water, what would be the temperature in °C?
Sunday, November 30, 2014 at 1:18am

introductory chemistry essentials
A 3.5 Liter sample of 5.8 M NaCL solution is diluted to 55 Liter. What is the molarity of the new solution?
Sunday, November 30, 2014 at 12:53am

Chemistry
Calculate the standard entropy, ΔS°rxn, of the following reaction at 25.0 °C using the data in this table. The standard enthalpy of the reaction, ΔH°rxn, is –44.2 kJ·mol–1. C2H4(G)+H20 ---> C5H5OH ΔS°rxn= ______ J*K^-1*mol^-1 ...
Sunday, November 30, 2014 at 12:38am

Chemistry
A solution is prepared that contains 0.0200 M AgNO# and 0.150 M KSCN. What is the equilibrium concentration of Ag+ ion in this solution? The Kf for Ag(SCN)4^3+ is 1.21x10^10 I'm not even sure how to set up this problem? Would I need to do an ice box? Ag(SCN) --> Ag+ + SCN
Saturday, November 29, 2014 at 11:24pm

chemistry
A solution contains 3.10 g of solute in 10.4 g of solvent. What is the mass percent of the solute in the solution?
Saturday, November 29, 2014 at 11:02pm

Chemistry
75.0 mL of a 1.40 M solution is diluted to a volume of 248 mL. A 124-mL portion of that solution is diluted using 165 mL of water. What is the final concentration?
Saturday, November 29, 2014 at 10:47pm

chemistry
What is the maximum amount of silver in grams that can be plated out of 3.8L of an AgNO3 solution containing 3.3% Ag by mass? (Assume that the density of the solution is 1.02g/mL .)
Saturday, November 29, 2014 at 9:30pm

Chemistry
What would you do in order to solve this question: "The enthalpy of combustion for benzoic acid is -3223.6kj/mol. Use the values of the standard enthalpies of formation of liquid water and CO2 to calculate standard enthalpy of formation of benzoic acid."
Saturday, November 29, 2014 at 9:27pm

chemistry
I'm working on substitution organic chemistry problems and I just had a question. There's an equation in which a molecule is treated with methanol in an acetone solution. Would the reaction be SN1 or SN2? I thought that it was SN2 because of the aprotic acetone, but ...
Saturday, November 29, 2014 at 8:59pm

Chemistry
During a Breathalyzer Test it was determined that 1.60mg of K2Cr2O7 was consumed by the above reaction. Calculate the number of milligrams of ethanol in the test sample.
Saturday, November 29, 2014 at 8:54pm

chemistry
Determine the pH (to two decimal places) of a solution prepared by adding 395 mL of 0.0360 M benzoic acid (C6H5COOH) to 12.5 g of sodium benzoate (NaC6H5COO).
Saturday, November 29, 2014 at 8:41pm

Chemistry
Let’s assume you have 250 ml of a 1.3M KOH solution and you want to neutralize it with the acid HBr. It takes 350 ml of the HBr solution to do so. What must have been the molarity of the HBr solution? HBr(aq) + KOH(aq) => KBr(aq) + H2O(l) The stoichiometry is already ...
Saturday, November 29, 2014 at 6:59pm

Chemistry
For an H+ concentration, [H+], of 4.3 x 10-4 M, would this be acidic, neutral or basic? Why? I'm assuming that because it is an H+ it would be acidic and H+ means acidic and OH- means base. Is this correct? And is there a better formula for this equation?
Saturday, November 29, 2014 at 6:53pm

Chemistry
What does 0.053 M NaCl mean? How many grams of sodium chloride are needed to make 5.0 liters of this solution?
Saturday, November 29, 2014 at 5:37pm

Chemistry
To make 250 ml of a 5%(w/v) calcium carbonate solution, how many grams of calcium carbonate will I need?
Saturday, November 29, 2014 at 5:35pm

chemistry
nitric acid is composed of HNO3 molecule.A sample of 4.50 g was obtained. calculate the number of oxygen atom in the sample. this is what i do .can u check if i am wrong or miss something answer : mole HNO3 = 4.50g/63 = 0.07 mol mole : no of particle/NA = 0.07x (avogardo ...
Saturday, November 29, 2014 at 5:10pm

chemistry
A balloon filled with 85 g of nitrogen gas that produced a pressure of 3.25 atm at 58C. What is the volume of the balloon/
Saturday, November 29, 2014 at 5:00pm

Chemistry
hydrogen gas is collected over water at a total pressure of 744 mm Hg at 20.0 C. If the volume of the wet hydrogen is 495 mL, what will the dry volume be at standard conditions? I know that you need to subtract the water vapor pressure from the total and I got 726.45 mmHg. (...
Saturday, November 29, 2014 at 4:35pm

chemistry
To make a phosphorus fertilizer, agricultural companies use the following reaction: Ca3P2O8 + 2H2SO4 --> CaH4P2O8 + 2CaH4SO6 (fertilizer) If 1.50 * 10^4 grams of H2SO4 are reacted with excess Ca3P2O8 and H2O, how many grams of fertilizer can be made? Hi, I pretty much get ...
Saturday, November 29, 2014 at 3:20pm

chemistry
What volume of a 0.550 M solution of potassium hydroxide can be made with 14.3 g of potassium hydroxide? (Ignore significant figures for this problem.)
Saturday, November 29, 2014 at 3:16pm

chemistry
cal culate the ph of a mixture of 100 ml distilled water and 2 ml of 2M of NaOH
Saturday, November 29, 2014 at 1:08pm

chemistry
titration of 50ml of 0.25ammonia with 0.5M HCL . a) find the initial PH value b) volume of HCL is required to reach the equivalent poinnt c)the ph at the equivalence point
Saturday, November 29, 2014 at 12:59pm

Chemistry
What are the steps to solve this problem? "The enthalpies of combustion of glucose and ethanol are -2813kj/mol and -1369kj/mol, use Hess's law to calculate the enthalpy change when 0.500 kg of glucose is allowed to ferment." Please help.
Friday, November 28, 2014 at 11:18pm

Chemistry
I'm not sure how to calculate the ΔH°rxn for 3 Al + 3 NH4ClO4 -> Al2O3 + AlCl3 + 3 NO + 6 H2O. I'm honestly not sure where to start with this problem.
Friday, November 28, 2014 at 9:09pm

Chemistry
Given that many laboratory gases are sold in steel cylinders with a volume of 43.8 L, What mass (in grams) of argon is inside a cylinder whose pressure is 17810kPa at 24∘C? I've attempted this problem but I'm not getting the correct answer. Please explain if you ...
Friday, November 28, 2014 at 8:09pm

Chemistry
If 14.5g of CO2 gas has a volume of 0.13L at 305K , what is its pressure in millimeters of mercury? I've plugged these values into the equation P=nRT/V but I am having troubles with canceling labels and getting the correct answer. Please explain as much as possible to me!
Friday, November 28, 2014 at 8:08pm

Chemistry
At 2000°C the equilibrium constant for the reaction is Kc = 2.4 ✕ 103. 2 NO(g) equilibrium reaction arrow N2(g) + O2(g) If the initial concentration of NO is 0.160 M, what are the equilibrium concentrations of NO, N2, and O2? I do not even know how to ...
Friday, November 28, 2014 at 5:19pm

Chemistry
Calculate Delta H for the following equation: Zn(s) + 2H+(aq) = Zn2+(aq) + H2(g)
Friday, November 28, 2014 at 1:16pm

chemistry
the volume of a certain bacterial cell is 1.44 μm3. what is the volume of 1 x 10 ^5 cells in liters
Friday, November 28, 2014 at 12:44pm

chemistry
At temperatures above 0°C, what is the sign of the change in free energy for the conversion of liquid water to ice? A. Positive B. Zero C. Negative D. Not known
Thursday, November 27, 2014 at 11:18pm

chemistry
3CuCl2 *2H2O + 2Al = 3Cu + 2AlCl3 + 6H2O Determine the number of grams that should have been produced when 1.25g of copper (2) chloride dehydrate reacts with excess aluminum so i'm not really sure how you're supposed to calculate the number of grams with hydrates?? ...
Thursday, November 27, 2014 at 9:45pm

Chemistry
I don't know how to do this question, or even start it. Please Help. 2 kg copper kettle (specific heat capacity 0.385j/gC) has .0500 kg of water at 20C. How much heat is needed to raise the temperature of the kettle and content to 80C?
Thursday, November 27, 2014 at 9:17pm

Chemistry
compose the micelle 2 agno3 + bacl2 - 2Agcl + ba (no3) 2
Thursday, November 27, 2014 at 8:00am

chemistry
can you please give me one practical application of analytical chemistry in being a medical technologist? i know it will determine the separation event happening on the lab test... but is that already a practical application? or i have to cite a deeper example? please give me ...
Thursday, November 27, 2014 at 6:20am

chemistry
A sample of gas in a balloon has an initial temperature of 9.0∘C and a volume of 1.75×103L . If the temperature changes to 80.∘C , and there is no change of pressure or amount of gas, what is the new volume, V2, of the gas?
Thursday, November 27, 2014 at 2:36am

chemistry
If the ΔH for H2O(l) → H2O(s) is -6.01 kJ, then what is the ΔH for 2H2O(s) → 2H2O(l)? A. -12.02 kJ B. 6.01 kJ C. -6.01 kJ D. 12.02 kJ I think d is the answer
Thursday, November 27, 2014 at 12:25am

Chemistry
At temperatures above 0°C, what is the sign of the change in free energy for the conversion of liquid water to ice? A. Positive B. Zero C. Negative D. Not known
Thursday, November 27, 2014 at 12:24am

chemistry
For which of the reactions listed below will Gibbs free energy always be negative? A. An exothermic reaction that increases in entropy B. An endothermic reaction that decreases in entropy C. An endothermic reaction that increases in entropy D. An exothermic reaction that ...
Thursday, November 27, 2014 at 12:23am

Chemistry
The reaction: H2C2O4 + CuO + Heat = ? This reaction was produced in organic elemental analysis to identify C and H. So I think CO2 is formed to react with Ca(OH)2 to giving CaCO3. Additionally was formed H2O, so I though H2 or H2O was produced. Is correct : = C2CuO4 + CO2 + H2 ?
Wednesday, November 26, 2014 at 9:19pm

Chemistry
copper is a product of the reaction that occurs when dry ammonia is passed over a sample f heated copper(2) oxide.The equation for the reaction is given: 2NH3+3CuO=3Cu+3H2O+N2 Calculate the mass of copper produced if 0.12dm^3 of nitrogen is produced at room temperature and ...
Wednesday, November 26, 2014 at 9:13pm

Chemistry
What is Gibbs free energy? A. The energy lost as heat to the surrounding molecules B. The usable energy released or absorbed by a reaction C. The energy in the form of kinetic energy in a system D. The energy contained within the bonds of molecules
Wednesday, November 26, 2014 at 6:32pm

chemistry
What is the balanced chemical equation of Shampoo? And what is the chemical reaction of it? Please i need a help ASAP! Thank you!
Wednesday, November 26, 2014 at 6:16pm

chemistry
What is the balanced chemical equation Shampoo? please i need a help ASAP!
Wednesday, November 26, 2014 at 6:03pm

chemistry
State the number of valence electrons for an iron(II) ion in an ionic bond.
Wednesday, November 26, 2014 at 5:07pm

Chemistry
please help! I don't understand any of this. Using the Solubility Rules, write the balanced molecular, total ionic, and net ionic equations (including physical states) for the following: Hints: There is no such thing as an Na3+. Na is in group 1A, so you know it can only ...
Wednesday, November 26, 2014 at 3:19pm

Chemistry
1. Write a balanced molecular equation for the reaction of solid AgNO3 with aqueous NaCl. Be sure to include the correct number of coefficients and the state of the species (aq, s, l or g). 2. Write the total ionic equation for this reaction, including all physical states. 3. ...
Wednesday, November 26, 2014 at 3:17pm

CHEMISTRY
write oxidation and reduction halfreaction of 3CuO+2NH3>3Cu+N2+3H2O
Wednesday, November 26, 2014 at 10:05am

CHEMISTRY
how can different steps in the analytical process help in solving probs in Analytical Chemistry
Wednesday, November 26, 2014 at 7:59am

chemistry
can you please give me some practical applications of qualitative chem and quantitative chem...
Wednesday, November 26, 2014 at 7:58am

CHEMISTRY HELP
how can analytical chemistry help on different fields of sciences and technology?
Wednesday, November 26, 2014 at 7:57am

Chemistry
What is the formula for copper chloride dihydrate ? And can 1 get more info on it plz (like an overall overview) ? Tnx
Wednesday, November 26, 2014 at 4:42am

chemistry
The G value for formation of gaseous water at 298 K and 1 atm is -278 kJ/mol. What is the nature of the spontaneity of formation of gaseous water at these conditions? A. The reaction is never spontaneous. B. The reaction is sometimes spontaneous. C. The reaction is spontaneous...
Tuesday, November 25, 2014 at 11:48pm

chemistry
Calculate the pressure exerted by 1.2 mol\rm mol of gas in a volume of 28.2 L\rm L and at a temperature of 334 K\rm K.
Tuesday, November 25, 2014 at 11:08pm

chemistry----please help
calculate the molar hydroxide ion concentration of each of the following solutions given the pH 4.53. Answer should be for OH-. Please show me how to do this in step by step I tried putting in 10 xy-4.53= 0.000029512 which is 3.0 * 10^-5 It says that the answer is wrong.
Tuesday, November 25, 2014 at 10:33pm

Chemistry
100 mL of LiNO3, 0.241 M is mixed with 240 mL of 0.618 M Ca(NO3)2. What is the final concentration of NO3- in the solution?
Tuesday, November 25, 2014 at 9:25pm

Chemistry
4P + 50_2 ---> 2P205 25.4g of P are used with excess 02 how many grams of p205 should theoretically form I have no idea where to start im lost
Tuesday, November 25, 2014 at 9:20pm

Chemistry
calculate the molar hydroxide ion concentration of each of the following solutions given the pH 4.53. Answer should be for OH-. Please show me how to do this in step by step
Tuesday, November 25, 2014 at 8:49pm

chemistry
State the number of valence electrons for a chloride ion in an ionic bond.
Tuesday, November 25, 2014 at 8:39pm

chemistry
State the number of valence electrons for an iron(II) ion in an ionic bond.
Tuesday, November 25, 2014 at 8:38pm

chemistry
Assuming all gases are at the same temperature and pressure, how many milliliters of hydrogen gas must react to give 49.0mL of NH3? 3H2(g)+N2(g)→2NH3(g)
Tuesday, November 25, 2014 at 8:14pm

Chemistry
Assuming all gases are at the same temperature and pressure, how many milliliters of hydrogen iodide are produced from 160mL of H2? H2(g)+I2(g)→2HI(g)
Tuesday, November 25, 2014 at 8:14pm

chemistry
How many milliliters of oxygen gas at STP are released from heating 5.15g of calcium chlorate? Ca(ClO3)2(s)→CaCl2(s)+3O2(g)
Tuesday, November 25, 2014 at 8:14pm

Chemistry
A substance has the following properties: Heat capacities: 1.34 J/g oC (solid) 3.02 J/g oC (liquid) 2.55 J/g oC (gas) Heat of Fusion = 4.23 kJ/mole Heat of Vaporization = 23.5 kJ/mole Boiling Point = 88.5 oC Melting Point = -30.0 oC Molar Mass = 96.3 g/mole How much energy (in...
Tuesday, November 25, 2014 at 7:55pm

Chemistry
0.15 grams of benzene (C6H6) is dissolved into 4.7 grams of melted biphenyl. The freezing point of the mixture was determined to be 4.7 degrees below the freezing point of pure biphenyl. Based on these results, what is the Kf of biphenyl? (Use the standard units in your ...
Tuesday, November 25, 2014 at 6:14pm

Chemistry
What is Gibbs free energy? A. The energy lost as heat to the surrounding molecules B. The usable energy released or absorbed by a reaction C. The energy in the form of kinetic energy in a system D. The energy contained within the bonds of molecules
Tuesday, November 25, 2014 at 5:59pm

chemistry
What is ΔH in the equation ΔG = ΔH - TΔS? A. The change in specific heat between the products and the reactants B. The change in enthalpy between products and reactants in a reaction C. The change in entropy between products and reactants in a reaction D. ...
Tuesday, November 25, 2014 at 5:34pm

chemistry
What would cause entropy to increase in a reaction? A. The products forming a more rigid structure B. The products forming an ordered pattern C. The products becoming more spread out D. The products forming fewer molecules I think the answer is c or d
Tuesday, November 25, 2014 at 5:13pm

Chemistry help drbob222
Which of the following processes would result in a negative entropy change? A. Leaves falling off a tree B. A deck of cards falling on the floor C. A piece of cake crumbling as it is cut D. A student filing papers I think d
Tuesday, November 25, 2014 at 4:17pm

Chemistry
If the student collected 3.46g of acetone and the theoretical yield is 3.67 g, what is the percent yield?
Tuesday, November 25, 2014 at 3:49pm

Chemistry
How many grams of oxygen gas must react to give 2.80g of ZnO? 2Zn(s)+O2(g)→2ZnO(s)
Tuesday, November 25, 2014 at 3:47pm

Chemistry
How many grams of oxygen gas must react to give 2.80g of ZnO?
Tuesday, November 25, 2014 at 3:43pm

Chemistry
Given the molar concentration of hydroxide ion, calculate the concentration of hydrogen ion. [OH-]=0.0010 Can someone please help me with this process. Thanks
Tuesday, November 25, 2014 at 3:23pm

Chemistry
Determine the acid and base that were neutralized to produce each of the following salts. Li2CO3 (aq). I don't understand how to solve this.
Tuesday, November 25, 2014 at 2:41pm

Chemistry
If 45.5 g of calcium carbonate is reacted with phosphoric acid, how many grams of carbon dioxide will be produced if the reaction yield is 85.0 %?
Tuesday, November 25, 2014 at 2:40pm

Chemistry
Given the molar concentration of hydrogen ion, calculate the concentration of hydroxide ion [H+]=7.9*10-7
Tuesday, November 25, 2014 at 2:39pm

Please Help Me With This Chemistry HW Question!
Should 25 ml of 0.15 M HCL solution be added to 250 mL of buffer solution containing 0.25M HF Ka-7.1 x 10, and 0.40 M NaF at a pH of 3.15 what is the new pH?
Tuesday, November 25, 2014 at 2:27pm

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