Monday
May 25, 2015

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
Describe the following types of corrosion and give a practical example of each 1.pure chemical corrosion 2.pure electrochemical corrosion
Tuesday, April 7, 2015 at 9:46am

Chemistry
What is the volume, in milliliters, required to prepare a. 20.0 mL of a 0.250 M KNO3 solution using a 6.00 M KNO3 solution b. 25.0 mL of a 2.50 M H2SO4 solution using a 12.0 M H2SO4 solution c. 0.500 L of a 1.50 M NH4Cl solution using a 10.00 M NH4Cl solution
Monday, April 6, 2015 at 10:50pm

Chemistry
Sodium vapor lamps are often used in residential street lighting. Sodium gives off two yellow lines of light having frequencies of 5.09 × 1014 Hz and 5.08 × 1014 Hz. What is this wavelengths of light in nm? would I start by using the following formula ƛ=c/v &#...
Monday, April 6, 2015 at 10:44pm

Chemistry
The Ka for the reaction of acetic acid and water is 1.8 x 10-5. Which of the following statements is true at pH 7? A.) there is much more acetic acid than acetate ion B.) there is more acetate ion than acetic acid C.) the concentration of acetate ion is equal to that of acetic...
Monday, April 6, 2015 at 10:05pm

Chemistry
The ethylammonium ion, CH3CH2NH3+, has a pKa of 10.81. It reacts with water to form ethylamine, CH3CH2NH2 and H3O+. Which of the following statements is true at pH 7? A.) ethylamine predominates B.) ethylammonium ion predominates C.) the pH is higher than pKa of the ...
Monday, April 6, 2015 at 10:03pm

Chemistry
If you have 324 grams KBr and want to produce a 1.48 M solution in water how many grams of water are needed?
Monday, April 6, 2015 at 9:51pm

Chemistry
Can anyone help me identify the solute and solvent in each solution with the steps if possible? Thanks! a. 10mL of acetic acid and 200mL of water b. 100.0g of water and 5.0g of sugar c. 1.0mL of Br2 and 50.0mL of methylene chloride
Monday, April 6, 2015 at 9:26pm

Chemistry (isotonicity)
How many milligrams of NaCl should be used to make the following prescription isotonic? Dextrose anhydrous 2.5% Sodium chloride q.s. Sterile water for injection Ad 1L There is only dextrose anhydrous 5% available
Monday, April 6, 2015 at 9:11pm

chemistry
a container with an initial volume of 6 liters at a temperature of 30 degrees celsius with a pressure of 2atm is changed so the temperature is now 90 degrees celsius and the volume is 8 liters. calculate the new pressure
Monday, April 6, 2015 at 8:55pm

Chemistry
How many grams of AlNO3 could be used to make the following prescription isotonic? Sol.Silver Nitrate 2.5% Sodium chloride q.s. Sterile water for injection There is only anhydrous dextrose 5% available
Monday, April 6, 2015 at 8:12pm

chemistry
calculate the density of NH3 gas at s.t.p.
Monday, April 6, 2015 at 8:04pm

Chemistry
A 25.00 mL sample of HCl was titrated with 35.79 mL of 0.250 M KOH. The concentration of the HCl solution is:
Monday, April 6, 2015 at 7:47pm

Chemistry
Consider the reaction between acetylene, C2H2, and oxygen in a welding torch: If 5.4 moles of acetylene react with sufficient oxygen, how many grams of CO2 will be formed?
Monday, April 6, 2015 at 1:20pm

Chemistry
Calculate the solubility of Ag2CrO4 in a) 0.05M KClO4 b) 0.005M AgNO3 a) I have figured out: Ag2CrO4=2Ag- + CrO42- Ksp=1.12*10^-12. Ksp=[2Ag]^2*[CrO4] Ksp=(2x)^2(x) = 1.12*10^-12=4x^3= x=2.65*10^-5 (?) b)Ag2CrO4=2Ag- + CrO42- Ksp=1.12*10^-12. Ksp=(2[Ag-]+0.005M)^2*[CrO42-] 1....
Monday, April 6, 2015 at 1:07pm

chemistry
how would you prove that sodium hydroxide is a base without wing litmus paper?
Monday, April 6, 2015 at 12:49pm

Chemistry
Instead of using ratios for back titrations we can also use molarities if our solutions are standardized. A 0.188g sample of antacid containing an unknown amount of triprotic base Al(OH)3 was reacted with 25.0mL of 0.101M HCl. The resulting solution was then titrated with 10....
Monday, April 6, 2015 at 11:00am

Chemistry
0.688g of antacid was treated with 50.00ml of 0.200M HCl. The excess acid required 4.21 mL of 1.200 M NaOH for back-titration. What is the neutralizing power of this antacid expressed as mmol of HCl per gram of antacid? I think the answer should be: (50.00ml HCl)(0.200M HCl)= ...
Monday, April 6, 2015 at 10:25am

chemistry
The Kw of water varies with temperature. Calculate the pH of water at 46⁰C with a Kw = 1.219 x 10-14. Show all calculations leading to an answer.
Monday, April 6, 2015 at 12:14am

chemistry
If 5.40 kcal of heat is added to 1.00 kg of ice at 0⁰C, how much liquid water at 0⁰C is produced? Show all calculations leading to an answer.
Monday, April 6, 2015 at 12:13am

chemistry
When a 2.5 mol of sugar (C12H22O11) are added to a certain amount of water the boiling point is raised by 1 Celsius degree. If 2.5 mol of aluminum nitrate is added to the same amount of water, by how much will the boiling point be changed?
Sunday, April 5, 2015 at 11:48pm

chemistry
If 5.40 kcal of heat is added to 1.00 kg of ice at 0⁰C, how much liquid water at 0⁰C is produced?
Sunday, April 5, 2015 at 11:47pm

chemistry
The Kw of water varies with temperature. Calculate the pH of water at 46⁰C with a Kw = 1.219 x 10-14.
Sunday, April 5, 2015 at 11:46pm

chemistry
what is the rate law for NO+O3=NO2+O2 in second order reaction if [NO] Doubled
Sunday, April 5, 2015 at 10:15pm

chemistry
Why is the second derivative of a titration curve more accurate method to determine endpoints and equivalence points than the first derivative?
Sunday, April 5, 2015 at 5:44pm

chemistry
1)Which of the following single bonds has the greatest bond energy? B-F B-Cl B-I B-Br 2)What is the % ionicity of the bond you chose above? (answer in full percent, not a fraction) 3)What is the % ionicity of the weakest single bond above? (answer in full percent, not a ...
Sunday, April 5, 2015 at 12:20pm

chemistry
A thermally activated process (a reaction) takes four minutes at 816oC. How long will it take (in minutes) at 707oC if the activation energy is 150 kJ/mol? What is the % ionicity of the bond B_I&B_F?
Sunday, April 5, 2015 at 10:11am

Chemistry
The bubble in the tip of the buret is not removed prior to performing the NaOH standardization. Will the reported concentration of the NaOH be greater than, less than, or equal to the true concentration of the NaOH if the bubble is flushed from the buret during the titration? ...
Saturday, April 4, 2015 at 10:35pm

Chemistry
A 5.00 L flask with mass of 463.873 g is filled with Ar gas to 3 atm pressure at 292 k. (19 celsius + 273) what is the mass of flask and gas?
Saturday, April 4, 2015 at 8:23pm

chemistry
A 100 w lightbulb is place in a cylinder equipped with a moveable piston. The ligshtbulb is turned on for 0.015 hours, and the assembly expands from initial volume of 0.85 L to a final volume of 5.88 L against an external pressure of 1.0 atm. Use the wattage of the lightbulb ...
Saturday, April 4, 2015 at 4:55pm

chemistry
Uranium metal can be produced by reaction of uranium tetrafluoride (UF4) with calcium metal (Ca). The by-product of this reaction is calcium fluoride (CaF2). The reactor is charged with 292.0 kg of UF4 and 47.0 kg of calcium. Assume that the reaction goes to completion. The ...
Saturday, April 4, 2015 at 4:35pm

chemistry
Don't know where to begin. 1) A thermally activated process (a reaction) takes four minutes at 811°C. How long will it take (in minutes) at 748°C if the activation energy is 150 kJ/mol?
Saturday, April 4, 2015 at 3:20pm

Chemistry
am I doing this equation correctly, please help. K3PO4(aq) + Ba(NO3)2(aq) my answer: 3K(NO3)2(aq) + 2Ba(PO4)3(s) Double displacement precipitation
Saturday, April 4, 2015 at 3:17pm

chemistry
The volume of CO2 produced by the combustion of 20g of graphite containing 10% impurity will be?
Saturday, April 4, 2015 at 2:33pm

Chemistry
Consider the following equilibrium: At equilibrium, 4.0 × 10-2mol H2, 4.0 × 10-2mol CO, 1.0 × 10-2mol H2O and 1.0 × 10-2mol C were present in a 1.0L container. What is the value of Keq? a) 0.063 b) 16 c) 0.16 d) 6.3 I got b, but I'm not too certain ...
Saturday, April 4, 2015 at 1:52am

Chemistry
Hi, can you help with how to solve this equation? 50.0 gram sample of NaCl is added to water to create a 0.50 L solution. What volume of this solution is needed to create a 1.30 L solution that is 0.100 M NaCl? The choices provided: a) 152 mL b) 255 mL c) 87.6 mL d) 412 mL 10....
Friday, April 3, 2015 at 9:59pm

chemistry ap
Assume that 29.7 g of Al react with HCl according to the equation Al(s) + HCl(aq) −→ AlCl3(aq) + H2(g) at STP. How many moles of Al react? Remember to balance the equation first. Answer in units of mol. How many moles of H2 are produced? Answer in units of mol. How...
Friday, April 3, 2015 at 9:51pm

chemistry
Solid iron(III) hydroxide decomposes to produce iron(III) oxide and water vapor. 1.09 L of water vapor is produced at STP. How much iron(III) hydroxide was used? in g.
Friday, April 3, 2015 at 9:50pm

chemistry ap
20.0 L of methane (CH4) undergoes complete combustion at 0.961 atm and 20◦C. How much CO2 is formed? Answer in units of L.
Friday, April 3, 2015 at 9:16pm

chemistry ap
Nitric acid can be produced by the reaction of gaseous nitrogen dioxide with water. 3 NO2(g) + H2O(ℓ) −→ 2 HNO3(ℓ) + NO(g) If 734 L of NO2 gas react with water, what volume of NO gas will be produced? Assume the gases are measured under the same ...
Friday, April 3, 2015 at 9:16pm

chemistry
3.58 gram sample of an unknown gas is found to occupy a volume of 2.37 L at a pressure of 808 mm Hg and a temperature of 60 oC. What is the molecular weight?
Friday, April 3, 2015 at 8:44pm

chemistry ap
Assuming all volume measurements are made at the same temperature and pressure, what volume of hydrogen gas is needed to react completely with 3.25 L of oxygen gas to produce water vapor? Answer in units of L.
Friday, April 3, 2015 at 7:51pm

chemistry ap
Zinc reacts with 18.0 mL of 6.00 M cold, aqueous sulfuric acid through single replacement. a. How much zinc sulfate is produced? Answer in units of g
Friday, April 3, 2015 at 7:50pm

chemistry
determine the concentration of NH3(aq) that is required to dissolve 775 mg of AgCl(s) in 100.0 mL of solution. The Ksp of AgCl is 1.77× 10–10.] please help!!!!!!!
Friday, April 3, 2015 at 6:46pm

chemistry
How many particles are there in a mole of nitrogen dioxide molecules? How many total atoms are there in a mole of nitrogen dioxide molecules?How many nitrogen atoms? How many oxygen atoms?
Friday, April 3, 2015 at 2:45pm

Chemistry
Can someone help me with this question? Calculate the work for each of the following processes beginning with a gas sample in a piston assembly with T=305 K, P=1.79 atm, and V=4.29 (a) irreversible expensing against a constant external pressure of 1.00 atm to a final volume of...
Friday, April 3, 2015 at 1:56pm

chemistry
A 50.0 mL sample of 0.50 M HBr is titrated with 0.25 M KOH. What is the pH after the addition of 60.0 mL of KOH? A) 4.1 B) 13.4 C) 1.7 D) 2.0 E) 7.7 I'm confused on the process of solving this problem. My work so far: .050L X .50 mol/1L= .025 mol HBR .060L X .25 mol/1L= ....
Friday, April 3, 2015 at 12:40pm

chemistry
Estimate the pH of the solution that results when this added to 50 mL of 0.275 M Na2HPO4(aq) - 50 mL of 0.275 M HCl(aq)
Friday, April 3, 2015 at 11:59am

chemistry
Hello! I am struggling a bit with this problem A gas sample occupies 51.6 L at a pressure of 0.841 atm and 39.6 ºC. What is the amount of gas (mol) in this sample?
Friday, April 3, 2015 at 11:57am

chemistry
Given the equation Ag^+(aq) + 2NH3 (aq) -> [Ag(NH3)2]^+ (aq) kf= 2 x 10^7 determine the concentration of NH3(aq) that is required to dissolve 415 mg of AgCl(s) in 100.0 mL of solution. The Ksp of AgCl is 1.77× 10–10.
Friday, April 3, 2015 at 11:54am

Chemistry
Instead of using ratios for back titrations we can also use molarities if our solutions are standardized. A 0.188g sample of antacid containing an unknown amount of triprotic base Al(OH)3 was reacted with 25.0mL of 0.101M HCl. The resulting solution was then titrated with 10....
Friday, April 3, 2015 at 10:58am

chemistry
How many grams of solid ammonium chloride should be added to 1.50 L of a 0.224 M ammonia solution to prepare a buffer with a pH of 8.720 ?
Friday, April 3, 2015 at 10:47am

chemistry
If a solution is made 0.080 M in Mg(NO3)2, 0.075 M in aqueous ammonia, and 3.5 M in NH4NO3, will Mg(OH)2 precipitate? What is the pH of this solution?
Friday, April 3, 2015 at 12:07am

chemistry
what volume of a 0.247 M perchloric acid solution is required to neutralize 23.8 mL of a 0.156 M calcium hydroxide solution? _titration problem of acids/bases
Thursday, April 2, 2015 at 11:07pm

chemistry
How many molecules (not moles) of NH3 are produced from 3.55×10−4g of H2?
Thursday, April 2, 2015 at 10:10pm

chemistry
How many grams of H2 are needed to produce 12.22g of NH3?
Thursday, April 2, 2015 at 10:09pm

Chemistry
I am trying to solve a buffer problem. I know I need to use the Henderson-Hasselblach equation but I am not getting the correct answer. The problem is: Propionic acid is a weak monoprotic acid with Ka = 1.3×10-5 M. NaOH(s) was gradually added to 1.00 L of 1.29×10-2...
Thursday, April 2, 2015 at 9:11pm

Chemistry
Calculate the value of ΔS when 1.10mol of Br2(l) is vaporized at 58.8 ∘C
Thursday, April 2, 2015 at 6:43pm

Chemistry
When 85g of CH4 are mixed with 85g of O2 according to this equation: CH4 + 2O2 - cO2 + 2H2O What is the theoretical yield in gams of CO2? What is the percent yield if 45.7g of CO2 are produced? Please explain!
Thursday, April 2, 2015 at 4:50pm

Chemistry
the rate of diffusion of a gas having molecular weight just double of hydrogen gas is 30 ml/s.the rate of diffusion of hydrogen gas will be
Thursday, April 2, 2015 at 4:34pm

Chemistry
What is a balanced equation for a Base-Acid Titration?
Thursday, April 2, 2015 at 4:30pm

chemistry
17. Calculate H for the following reaction using Hess law H2 (g) + Br2 (g) → 2 HBr (g) Experimental information 2 H+ → H2 H -436.4 kJ 2 Br- → Br2 H -192.5 kJ 2 H+ + 2 Br- →2 HBr H -144.8 kJ
Thursday, April 2, 2015 at 4:06pm

Chemistry
Why can't milk of magnesia (Mg(OH)2), act as a buffer?
Thursday, April 2, 2015 at 2:25pm

Chemistry
The ph of a solution is 9.55 at 25degree celcius. What is the hydroxide-ion in the solution?
Thursday, April 2, 2015 at 12:16pm

Chemistry
For the reaction 4FeCl2(aq) + 3O2(g) - 2Fe2O3(s) + 4Cl2(g); how many grams of FeO3 are produced from 8.71 x 10 to the 21st power molecules of O2?? Help Please!
Thursday, April 2, 2015 at 11:04am

chemistry
Why do you add Sodium hydroxidein your reduction procedure
Thursday, April 2, 2015 at 7:59am

chemistry
assuming only glassware was supplied for the original experiment, what would be the procedural change necessary to titrate 25.00mL of commercial bleaching solution.
Thursday, April 2, 2015 at 5:37am

chemistry
You weigh out an antacid tablet and determine the mass to be 1.1990 g. After taking a 0.2455 g sample of the antacid tablet, you dissolve it in 25.00 mL of a 0.1006 M solution of hydrochloric acid in a 250.0 mL Erlenmeyer flask. After heating the solution to get rid of carbon ...
Thursday, April 2, 2015 at 12:53am

chemistry
What is the heat involved when 3.00 g of aluminum oxide is formed?
Thursday, April 2, 2015 at 12:20am

chemistry
calculate the grams of 1.8% (m/m) NaCl solution that contains 8.00 g of NaCl I tried 1.8 times 8.00g divided by 58.44g times 100 my answer is 24.6g rounded to 2 SF is 25g this truned out to be wrong I'm stumped!
Wednesday, April 1, 2015 at 10:40pm

chemistry
calculate delta G at 298 K when 5.0 atm H2 and 3.0 atm of CO2 are converted to methanol.
Wednesday, April 1, 2015 at 9:39pm

Chemistry
How many moles of HNO3 are present if 0.116mol of Ba(OH)2 was needed to neutralize the acid solution?
Wednesday, April 1, 2015 at 9:03pm

chemistry
Aqueous hydrobromic acid will react with solid sodium hydroxide to produce aqueous sodium bromide and liquid water . Suppose 4.05 g of hydrobromic acid is mixed with 0.86 g of sodium hydroxide. Calculate the maximum mass of water that could be produced by the chemical reaction...
Wednesday, April 1, 2015 at 9:00pm

Chemistry
High concentration of iron (III) ions, Fe3+, cause hard water. Write a balanced equation to show how iron ions can be removed using sodium carbonate, NaCO3.
Wednesday, April 1, 2015 at 8:43pm

chemistry
A 1.0 x 10-2 M solution of a weak acid is found to be 3.7% dissociated. Calculate Ka of this acid. I found the amount dissociated by (amount dissociated/initial conc)*100=3.7 Where do I go from here?
Wednesday, April 1, 2015 at 8:38pm

Chemistry
What would be the procedure for titrating a beverage to determine the concemtration of weak acid? What reagents would be needed? What appropiate measurements and observations must be made?
Wednesday, April 1, 2015 at 8:23pm

chemistry help
a 3.54 grams solid sample of an unknown monoprotic acid was dissolved in distilled water to produce a 47.0 mL solution at 25 degrees. This solution was then titrated with 0.2 M NaOH. The equivalence point was reached when 35.72 mL of 0.2 M NaOH was delivered. A. find the ...
Wednesday, April 1, 2015 at 8:16pm

chemistry help
In the following questions, assume that no excess distilled water was added from a wash bottle during the titration of 10.00 mL of vinegar with your standardized solution of NaOH. A. calculate the pH of vinegar. B. what was the pH of the solution after 4.00 mL of titrant was ...
Wednesday, April 1, 2015 at 8:16pm

chemistry help
A 15.00 mL sample of an unknown monoprotic weak acid solution is titrated with 0.35 M NaOH. The initial buret reading is 0.23 mL. The phenolphthalein indicator turns the solution light pink when the buret reads 29.58 mL. B. How many moles of NaOH were delivered? C. How many ...
Wednesday, April 1, 2015 at 8:14pm

Chemistry
The chemical equation for ionic reaction between Na2S and AgNO3??
Wednesday, April 1, 2015 at 7:05pm

Chemistry
How many moles of H2O are in 12.7 grams of H2O?
Wednesday, April 1, 2015 at 5:11pm

Chemistry
how many grams of Nano3 are in 0.755 moles of nano3
Wednesday, April 1, 2015 at 5:09pm

Chemistry
how many grams of sugar would be needed to give a 50.00 mL solution of FD&C Red Dye a concentration of 6.0% sugar?
Wednesday, April 1, 2015 at 4:38pm

chemistry
calculate delta G at 298 K when 5.0 atm H2 and 3.0 atm of CO2 are converted to methanol. I know you can calulate for Q and use that but how do you do the calculation when you dont have the atm for the final product.
Wednesday, April 1, 2015 at 4:17pm

chemistry
calculate the change in pH when 5 ml of 0.01M HNO3 is added to 50 ml of water. I know how to calculate pH, but not when it is changing.
Wednesday, April 1, 2015 at 3:28pm

chemistry
Calculate the molarity of a solution made by adding 47.2g of NaNO3 to a flask and dissolving it with water to create a total volume of 1.80L .
Wednesday, April 1, 2015 at 1:56pm

chemistry
How many grams of sucrose (C12H22O11) are in 2.50L of 0.710M sucrose solution?
Wednesday, April 1, 2015 at 1:56pm

Chemistry
A student generated oxygen gas by decomposing hydrogen peroxide (H2O2) according to the following equation: 2H2O2(aq) -> 2H2O(l) + O2(g) If the student started with 1.75 moles of hydrogen peroxide, how many moles of oxygen gas would be produced? Show your work. ((If you can...
Wednesday, April 1, 2015 at 1:55pm

Chemistry
how many grams of KCIO3 can be dissolved it 50 g h20 at 50 degrees celcuis?
Wednesday, April 1, 2015 at 1:31pm

chemistry
In the following questions, assume that no excess distilled water was added from a wash bottle during the titration of 10.00 mL of vinegar with your standardized solution of NaOH. A. calculate the pH of vinegar. B. what was the pH of the solution after 4.00 mL of titrant was ...
Wednesday, April 1, 2015 at 11:59am

chemistry
A 15.00 mL sample of an unknown monoprotic weak acid solution is titrated with 0.35 M NaOH. The initial buret reading is 0.23 mL. The phenolphthalein indicator turns the solution light pink when the buret reads 29.58 mL. A. what volume of 0.35 M NaOH was delivered? B. How many...
Wednesday, April 1, 2015 at 11:42am

chemistry
a 3.54 grams solid sample of an unknown monoprotic acid was dissolved in distilled water to produce a 47.0 mL solution at 25 degrees. This solution was then titrated with 0.2 M NaOH. The equivalence point was reached when 35.72 mL of 0.2 M NaOH was delivered. A. find the ...
Wednesday, April 1, 2015 at 11:27am

chemistry
the complete electrolysis of 90 grams of water will yield
Wednesday, April 1, 2015 at 8:41am

chemistry
0.1 mol of an organic acid is added to 600 ml of 0.5M KOH solution. The resulting basic solution can be neutralized by 200 ml of 0.5 M HCl solution. Which acid is ot?
Wednesday, April 1, 2015 at 8:26am

chemistry
At a certain elevation, the boiling point of water is 98.5°C. How much energy is needed to heat 35.0 mL of water to the boiling point at this elevation if the water initially was at 23.4°C? (Cp=75.38J/(mol*C), d= 1.00g/mL)
Wednesday, April 1, 2015 at 3:21am

chemistry
how to prepare 1 L of 2.5M nitric acid from 69% of concentrated nitric acid?
Wednesday, April 1, 2015 at 12:07am

chemistry
You find the Ka of your unknown acid is 6.3x10 -5 . If you are being asked to make a buffer at pH 4.00, what is the appropriate ratio of A- to HA to be combined in your flask?
Tuesday, March 31, 2015 at 11:57pm

chemistry
You measure the pH of a 0.50 M unknown acid solution using a pH meter and it is found to be 1.74. What is Ka for the acid? I know ph=-log{H+} Where do I go from here?
Tuesday, March 31, 2015 at 11:48pm

Chemistry physics
3.25x10-3 kg of gold is deposited onto the negative electrode of an electrolytic cell in a period of 2.78 hours, what is the current through this cell in amperes? Assume that the gold ions carry one elementary unit of charge
Tuesday, March 31, 2015 at 11:42pm

chemistry to MathMate
Chemistry - CJ, Tuesday, March 31, 2015 at 10:53pm I am experiencing a major block.... I can't say.... 1micrometer= 1000nm 5micrometer= x..... because I'll get back the same thing So please help me, tell me the answer please.
Tuesday, March 31, 2015 at 10:57pm

physical chemistry
I need to make a solution of 50% ethanol in water (by mass). The partial molar volume of water is 17.0mL/mol and the partial molar volume of ethanol is 52.0mL/mol. What is the density of this solution/
Tuesday, March 31, 2015 at 10:18pm

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