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August 31, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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Chemistry
Calculate the pH at the equivalence point for the titration of 0.180 M methylamine (CH3NH2) with 0.180 M HCl. The Kb of methylamine is 5.0× 10–4.
Thursday, December 5, 2013 at 12:25pm

Chemistry Q1,3,5
1) What would be the preferred heating device (s) in each of the following situations? a) reflux a solvent with a 56 degree Celsius boiling point b) reflux a solvent with a 110 degree Celsius boiling point c) distillation of a substance that boils at 220 degree Celsius 3) What...
Thursday, December 5, 2013 at 11:07am

chemistry
I am having trouble understanding what the concept is for writing these out. Write a balanced nuclear equation for the alpha decay of each of the following radioactive isotopes: curium-243, 22589Ac
Thursday, December 5, 2013 at 9:40am

Chemistry
N2+3H2<--->2NH3 Decreasing nitrogen: Increases or decreases hydrogen? Increases or decreases ammonia? Decreasing hydrogen : Increases or decreases nitrogen? Increase or decreases ammonia?
Thursday, December 5, 2013 at 12:24am

Chemistry
The boiling point of a solution or mixture is always ________?
Thursday, December 5, 2013 at 12:02am

Chemistry
The freezing point of a solution or mixture is always ________ ?
Thursday, December 5, 2013 at 12:02am

Chemistry
What is the osmolar concentration of 1.000M CaCl2 solution
Thursday, December 5, 2013 at 12:00am

Chemistry
What is the molar concentration of the lead nitrate,potassium iodine,lead iodine,and the potassium nitrate after you mix 10.00mL of 0.200M Pb(NO3) and 30.00mL of 0.100M KI together balance the equation KI+Pb(NO3)2 PbI2+KNO3
Wednesday, December 4, 2013 at 11:59pm

Chemistry
Consider the following chemical reaction 2HCl+Ca(OH) CaCl+2H2O you have a mixed solution with 20.00mL of 0.100M Ca(OH)2 solution What is the molarity of the HCl,Ca(OH)2 and CaCl2 after the reaction has stopped?
Wednesday, December 4, 2013 at 11:55pm

Chemistry
What is the ( m/m) % concentration of a tin in a solution of 5.000 grams of tin dissolved in 95.000 grams of copper
Wednesday, December 4, 2013 at 11:51pm

Chemistry
What is the osmotic pressure in atmospheres of 40.00% ( m/v) NaCl solution at a temperature of 0.0 degrees celcius
Wednesday, December 4, 2013 at 11:48pm

Chemistry
What is the % ( m/ v) concentration of the calcium chloride solution 1000.00 grams which was dissolved in water to make 1000.00 mL of the solution
Wednesday, December 4, 2013 at 11:47pm

Chemistry
What is the osmotic pressure in atmospheres of a 15%(m/v) sucrose solution at a temperature of 25 degrees celcius
Wednesday, December 4, 2013 at 11:45pm

Chemistry
What is the % (m/v) concentration of the calcium chloride 1000.00mL
Wednesday, December 4, 2013 at 10:50pm

Chemistry
What is the molal concentration,m,of tin in a solution of 5.000grams of tin dissolved 95.000grams of copper
Wednesday, December 4, 2013 at 10:48pm

Chemistry
What is the osmotic pressure in atmospheres of a 15% sucrose solution at a temperature of 25 degrees celcius
Wednesday, December 4, 2013 at 10:47pm

Chemistry
What is the osmotic pressure of a 50% sucrose solution at a temperature of 37 degrees celcius with a molar mass of sucrose of 342.30 grams
Wednesday, December 4, 2013 at 10:46pm

Chemistry
What is the osmotic pressure in atmospheres of a 50% sucrose solution at a temperature of 37 degrees celcius with molar mass of 342.30grams of sucrose
Wednesday, December 4, 2013 at 10:38pm

Chemistry (DrBob222)
Is the relationship between delta G and Temperature inverse or direct?
Wednesday, December 4, 2013 at 9:37pm

chemistry
Solid aluminum carbonate decomposes to form solid aluminum oxide and carbon dioxide gas
Wednesday, December 4, 2013 at 9:19pm

chemistry
a 5.82 kg piece of copper metal is heated from 21.5c to 328.3. calculate the head absorbed. Assuming it doesn't undergo a phase change. Cu specific heat 0.385 j/g*c
Wednesday, December 4, 2013 at 7:25pm

chemistry
a 5.82 kg piece of copper metal is heated from 21.5c to 328.3. calculate the head absorbed. Assuming it doesn't undergo a phase change. Cu specific heat 0.385 j/g*c
Wednesday, December 4, 2013 at 7:09pm

chemistry college
Consider the titration of 30.0 mL sample of 0.050 M NH3 with 0.025 M HCl. Calculate the pH after the following volumes of titrant (acid)have been added: a)0 mL, b)20.0mL, c)60.0mL, d)65mL Kb for NH3 is 1.8 x 10^-5
Wednesday, December 4, 2013 at 5:33pm

Chemistry
Determine the molar mass of a compound and its molecular formula if a solution of 1.00 g of the unknown is dissolved in 50 grams of cyclohexane. Cyclohexane freezes at 6.02 oC. The normal freezing point of cyclohexane is 6.50 oC and its kf value is 20.2 oC/m. The percent ...
Wednesday, December 4, 2013 at 4:58pm

Chemistry
SHOW WORK A 44g sample of CO2 has a volume of 22.4 L at STP. The sample is heated to 71 degrees Celsius and compressed to a volume of 18.0 L. What is the resulting pressure?
Wednesday, December 4, 2013 at 4:03pm

Chemistry
SHOW WORK A cylinder contains 98g of air at 295K. The pressure in the cylinder is 174psi. If 32g of air are allowed to escape and the cylinder is heated to 335K, what is the new pressure?
Wednesday, December 4, 2013 at 4:01pm

Chemistry
SHOW WORK A cylinder contains 36.5g of argon gas at a pressure of 8.20atm. The valve is opened and gas is allowed to escape until the pressure is reduced to 4.75atm at constant temperature. How many grams of argon escaped?
Wednesday, December 4, 2013 at 3:59pm

Chemistry
SHOW WORK A cylinder contains 22g of air. If 77g of air are pumped into the cylinder at constant temperature, how does the pressure in the cylinder change?
Wednesday, December 4, 2013 at 3:56pm

Chemistry
SHOW WORK A cylinder containing 48g of nitrogen gas at room temperature is placed on a scale. The valve is opened and 12g of gas are allowed to escape. Assuming that the temperature of the cylinder remains constant, how does the pressure change?
Wednesday, December 4, 2013 at 3:54pm

chemistry
SHOW WORK How many moles of helium occupy 26.4 L at a pressure of 103.0 kPa, and 10 degrees Celsius? A.) 0.03 mole B.) 0.86 mole C.) 1.16 mole D.) 32.72 mole
Wednesday, December 4, 2013 at 3:51pm

chemistry calculations
An ore sample with a mass of 670 kg contains 27.7% magnesium carbonate .If all of the magnesium carbonate in this ore sample is decomposed to form carbon dioxide ,describe how to determine what mass of carbon dioxide is evolved during the process.
Wednesday, December 4, 2013 at 6:33am

chemistry calculations
when 2.750 g of the oxide of lead is heated to a high temperature,it decomposes to produce 0.0640 g of oxygen gas and 2.686 g of some new lead oxide compound.How can you use this data to determine the formula of the new compound?
Wednesday, December 4, 2013 at 6:23am

CHEMISTRY
CALCULATE THE MOLARITY OF 50.0g OF NaCL IN 7820mL OF SOLUTION
Wednesday, December 4, 2013 at 4:25am

Chemistry
If you have 10.00 mL of 0.5875 M H3PO4, how many mL of 0.2625 M NaOH are needed to reach the point of complete neutralization?
Wednesday, December 4, 2013 at 1:50am

Chemistry
Find the equilibrium constant. 1. The equilibrium constant for the reaction,! Fe3+ + SCN- ⇋ FeSCN2+ (at a specific temperature), can be determined by first preparing a standard solution of FeSCN2+ and comparing its absorbance of light to an equilibrium system of unknown ...
Tuesday, December 3, 2013 at 11:46pm

chemistry
hello this is ellie again. I need help on this one problem A solution of 0.314M KOH is used to neutralize 10.0mL H3PO4 solution. H3PO4(aq) + 3KOH(aq) → K3PO4(aq) + 3H2O(l) If 29.3mL KOH solution is required to reach the endpoint, what is the molarity of the H3PO4 ...
Tuesday, December 3, 2013 at 10:03pm

Chemistry
Two competing corporations are submitting data to the US Military to create chemical hot packs. The Military has stipulated that each hot pack may cost no more than 85 cents and must result in at least a 20degrees Celsius rise in temperature when activated. Which of the ...
Tuesday, December 3, 2013 at 9:45pm

CHEMISTRY
Find the equilibrium constant. 1. The equilibrium constant for the reaction,! Fe3+ + SCN- ⇋ FeSCN2+ (at a specific temperature), can be determined by first preparing a standard solution of FeSCN2+ and comparing its absorbance of light to an equilibrium system of unknown ...
Tuesday, December 3, 2013 at 9:03pm

chemistry
At equilibrium for the reaction A + 2B --> C + D <-- the concentration of A is 0.579 mol/L, the concentration of B is 0.598 mol/L, the concentration of C is 0.465 mol/L, and the concentration of D is 0.608 mol/L. What is the equilibrium constant for this reaction?
Tuesday, December 3, 2013 at 8:47pm

Chemistry
Consider the following chemical reaction 2HCL+ Ca(OH)2 CaCl2+2H2O You have mixed 30.00ml of 0.150 M HCl solution with 20.00ml of 0.100m Ca(OH)2 solution what is the molarity of the HCl, Ca( OH)2 and CaCl2 after the reaction has stopped
Tuesday, December 3, 2013 at 8:37pm

chemistry
A solution of 0.314M KOH is used to neutralize 10.0mL H3PO4 solution. H3PO4(aq) + 3KOH(aq) → K3PO4(aq) + 3H2O(lIf 29.3mL KOH solution is required to reach the endpoint, what is the molarity of the H3PO4 solution?)
Tuesday, December 3, 2013 at 8:02pm

chemistry
A volume of 12.47 mL of 0.1080 M NaOH solution was used to titrate a 0.583 g sample of unknown containing K2HPO4. What is the percent by mass of K2HPO4 in the unknown? In this problem what mass of sample in grams would be needed to deliver about 23.40 mL in the next trial? In ...
Tuesday, December 3, 2013 at 6:32pm

chemistry
A solution of 0.314M KOH is used to neutralize 10.0mL H3PO4 solution. H3PO4(aq) + 3KOH(aq) → K3PO4(aq) + 3H2O(l) If 29.3mL KOH solution is required to reach the endpoint, what is the molarity of the H3PO4 solution?
Tuesday, December 3, 2013 at 6:00pm

chemistry
Nitric acid reacts with silver metal: 4HNO3+3Ag yields NO+2H2O+3 AgNO3. Calculate the number of grams of NO formed when 10.8 g of Ag reacts with 12.6g of HNO3.
Tuesday, December 3, 2013 at 5:19pm

Chemistry
The specific heat for liquid ethanol is 2.46 J/(g•°C). When 210 g of ethanol is cooled from 50 °C to 5 °C, the surrounding 7.80 × 103 g of air absorbs the heat. The specific heat of air is 1.01J/(g•°C)
Tuesday, December 3, 2013 at 4:44pm

chemistry
A solution of 0.314M KOH is used to neutralize 10.0mL H3PO4 solution. H3PO4(aq) + 3KOH(aq) → K3PO4(aq) + 3H2O(l) If 29.3mL KOH solution is required to reach the endpoint, what is the molarity of the H3PO4 solution?
Tuesday, December 3, 2013 at 4:31pm

Chemistry
A gas, Y, diffuses 1.05 times faster than SO2 gas at the same conditions. What is the molecular weight of gas Y?
Tuesday, December 3, 2013 at 9:10am

chemistry
help balance HNO2+HNO3
Tuesday, December 3, 2013 at 4:36am

Chemistry 2
Durango redox reaction the oxidation number of species Will decretase, increpase or stay the same
Tuesday, December 3, 2013 at 12:49am

Chemistry
What volume of 5% vinegar solution is needed to neutralize 1.0g of baking soda if density is 1.01g/ml
Tuesday, December 3, 2013 at 12:46am

chemistry
how do you tell whether or not a compound is polar or non-polar?
Monday, December 2, 2013 at 9:25pm

chemistry
how do you tell whether or not a compound is polar or non-polar?
Monday, December 2, 2013 at 9:24pm

AP Chemistry
The system CO2(g) + H2(g)<->H2O(g) + CO(g) is at equilibrium at some temperature. At equilibrium a 4.00 L vessel contains 1.00 mole CO2, 1.00 mole H2, 2.40 moles H2O, and 2.40 moles CO. How many moles of CO2 must be added to the system to bring the equilibrium CO ...
Monday, December 2, 2013 at 9:18pm

chemistry
how do you tell whether or not a compound is polar or non-polar?
Monday, December 2, 2013 at 9:16pm

Chemistry
Describe the creation of 234 mL of a 3.2 M sodium chloride solution
Monday, December 2, 2013 at 8:04pm

Chemistry
What are the formulas of the salts that precipitate when the reaction mixture (n-butyl alcohol, sodium bromide, water, and sulfuric acid) is cooled?
Monday, December 2, 2013 at 6:16pm

chemistry
2.5g of magnesium is how many moles? How do i set it up? Help would be awesome thanks.
Monday, December 2, 2013 at 4:42pm

Chemistry
1. I do not understand why this cannot go to equilibrium? Na2CO3(aq)+HCl(aq)->H2O(l)+CO2(g)+NaC​l(aq) Please explain. 2. Are K subscript c the same as K subscript eq? Do they both stand for the equilibrium constant?
Monday, December 2, 2013 at 3:34pm

Chemistry
I do not understand why this cannot go to equilibrium? Na2CO3(aq)+HCl(aq)->H2O(l)+CO2(g)+NaC​l(aq)
Monday, December 2, 2013 at 2:57pm

chemistry
I have a balance equation but i need to know how to find the different states of each element. How do I do that? Ca + 2 HNO3 => Ca(NO3)2 + H2
Monday, December 2, 2013 at 2:02pm

chemistry
SO2Cl2(g) SO2(g) + Cl2(g) The Kp for the reaction is 2.18 at 648 K. A sample of SO2Cl2 is placed in a container and heated to 648 K while the total pressure is kept constant at 9.00 atm. Calculate the partial pressures of the gases at equilibrium.
Monday, December 2, 2013 at 7:09am

chemistry
Lysine, an essential amino acid in the human body, contains C,H,O and N only. In an experiment, the complete combustion of 2.175 g lysine gave 3.94 g of CO2 and 1.89 g of H2O. In another reaction, the nitrogen content of 1.873 g of lysine is quantitatively converted to 0.436 g...
Monday, December 2, 2013 at 7:02am

chemistry
convert 3.0m to yd
Sunday, December 1, 2013 at 8:17pm

CHEMISTRY
GIVE THE BOND ORDER FOR EACH BOND IN THE FOLLOWING MOLECULES OR IONS: CH2O,SO32-,NO2+,NOC1
Sunday, December 1, 2013 at 8:05pm

Chemistry- DrBob222
0.2g of an organic sample W, analysed by combustion analysis results in 0.48g of CO2 and 0.1636g of H2O. We had a second sample 0.2g of W again producing 0.0618g of ammonia. Show that only C, H and N exist in W and find its emperical formula.
Saturday, November 30, 2013 at 9:52pm

chemistry
a saturated solution of barium chloride at 30c contains 150g water. how much additional barium chloride can be dissolved by heating this solution to 60c
Saturday, November 30, 2013 at 9:28pm

Chemistry
Hello! I am having a little difficulty answering these two questions on my homework, I was wondering if anyone could please help me out! Thank you! 1) Consider the following balanced chemical equation for the neutralization reaction of calcium hydroxide with hydrochloric acid ...
Saturday, November 30, 2013 at 5:35pm

Chemistry
The specific heat of solid gold is 0.13 J/g • °C. How much heat is needed to raise the temperature of 25.0 g of gold from 23°C to its melting point at 1063°C?
Friday, November 29, 2013 at 4:33pm

Physical Chemistry
A pharmaceutical preparation of pH 6.2 is preserved with substance A (pKa 8.5). If the preservative effect is due to the undissociated molecule determine the per cent of active preservative present in the preparation. Thanks! :)
Friday, November 29, 2013 at 2:48pm

Chemistry
Weak polyprotic acids are normally added to Coca Cola to lower its pH to about 2.5 and impart tartness? Show that a two litter cocacola bottled drink that contains 0.057 to 0.084 percent of 75 percent of phosphoric acid by mass,meets this ph requirement. Pka1= 2.12
Friday, November 29, 2013 at 2:02pm

Chemistry
Weak polyprotic acids are normally added to Coca Cola to lower its pH to about 2.5 and impart tartness? Show that a two litter cocacola bottled drink that contains 0.057 to 0.084 percent of 75 percent of phosphoric acid by mass,meets this ph requirement. Pka1= 2.12
Friday, November 29, 2013 at 2:02pm

Chemistry
Determine The Mole Fraction Of Substances In Solution Containing 36g of water and 46g of glaycerine C3H5(OH)3.
Friday, November 29, 2013 at 12:27am

Chemistry
Determine The Mole Fraction Of Substances In Solution Containing 36g of water and 46g of glaycerine C3H5(OH)3.
Friday, November 29, 2013 at 12:25am

chemistry
A cylindrical glass of water (H2O) has a radius of 6.12 cm and a height of 9.91 cm. The density of water is 1.00 g/cm3. How many moles of water are contained in the glass?
Thursday, November 28, 2013 at 3:02pm

Chemistry
Is oxygen considered an diatomic molecule?
Wednesday, November 27, 2013 at 7:39pm

AP Chemistry
A mixture consisting of 1 mol of H2O(g) and 1 mol CO(g) is placed in a 11 L reaction vessel at 800 K. At equilibrium, 0.422 mol CO2(g) is present as a result of the reaction CO(g) + H2O(g)<->CO2(g) + H2(g). What is Kc at 800 K?
Wednesday, November 27, 2013 at 5:04pm

AP Chemistry
The equilibrium constant for the reaction PCl3(g) + Cl2(g)<-> PCl5(g) is 35000 at 760◦C. At equilibrium, the partial pressure of PCl5 was 110 bar and that of PCl3 was 9.98 bar. Calculate the equilibrium partial pressure of Cl2. Answer in units of bar
Wednesday, November 27, 2013 at 5:02pm

AP Chemistry
At 350 K, Kc= 0.142 for the reaction 2BrCl(g)<-> Br2(g) + Cl2(g) An equilibrium mixture at this temperature contains equal concentrations of bromine and chlorine, 0.049 mol/L. What is the equilibrium concentration of BrCl? Answer in units of M
Wednesday, November 27, 2013 at 5:00pm

AP Chemistry
At a certain temperature, the equilibrium constant Kc is 0.154 for the reaction 2SO2(g) + O2(g)<-> 2SO3(g) What concentration of SO3 would be in equilibrium with 0.250 moles of SO2 and 0.885 moles of O2 in a 1.00 liter container at this temperature? Note: These latter ...
Wednesday, November 27, 2013 at 4:59pm

Analaytical Chemistry
ahhh
Wednesday, November 27, 2013 at 7:47am

Chemistry
What is 0.7g of SO2 ..and how would you do this equation? Thanks,
Wednesday, November 27, 2013 at 7:28am

Chemistry
How many moles in 0.7g of SO2 ..and how would you do this! Thanks
Wednesday, November 27, 2013 at 7:27am

Chemistry
6. Explain how you would prepare this solution from powdered reagents and whatever glassware you needed: 3.0 L of 1.3 M NaOH
Wednesday, November 27, 2013 at 4:46am

Chemistry- DrBob222 Urgent Please help
Name these: a) CH2=CH-CH=CH2 b) CH3-CH=CH-C(TRIPLE BOND)CH c) CH3-CH2-CH2-CH(Cl)-CH(Br)-CH3
Tuesday, November 26, 2013 at 10:42pm

chemistry
A standard solution is prepared for the analysis of fluoxymesterone (C20H29FO3), an anabolic steroid. A stock solution is first prepared by dissolving 13.4 mg of fluoxymesterone in enough water to give a total volume of 500.0 mL. A 100.0-µL aliquot (portion) of this ...
Tuesday, November 26, 2013 at 10:42pm

CHEMISTRY
A chemist studying the equilibrium N2O4(g)<----->2NO2(g) controls the temperature so that keq ( equilibrium constant)= 0.028. At one equilibrium position, the concentration of N2O4 is 1.5 times greater than the concentration of NO2. Find the concentrations of the two ...
Tuesday, November 26, 2013 at 8:57pm

Chemistry
What are the individual orders of the reactants involved in the oxidation of methylene blue by ascorbic acid? Rate of reaction= [MB+]^m * [H2A]^n * [HCl]^p What are m, n, and p?
Tuesday, November 26, 2013 at 8:26pm

AP Chemistry
The equilibrium constant for thermal dissociation of F2 F2(g)<->2F(g) is 0.300. If initially 1.00 mol F2 is placed in a 1.00 L container, which of the following is the correct number of moles of F2 that have dissociated at equilibrium? 1. 0.130 mol 2. 0.418 mol 3. 0.548 ...
Tuesday, November 26, 2013 at 8:16pm

AP Chemistry
Analysis of a reaction mixture showed that it had the composition 0.43 mol/L N2, 0.541 mol/L H2, and 0.124 mol/L NH3 at 800 K, at which temperature Kc=0.278 for N2(g) + 3H2(g)<->2NH3(g). Calculate the reaction quotient Qc
Tuesday, November 26, 2013 at 7:55pm

AP Chemistry
The equilibrium constant Kp is 5.00×10^17 at 25◦C for the reaction C2H4(g) + H2(g)<->C2H6(g). From this information, calculate ∆G0 at 25◦C
Tuesday, November 26, 2013 at 7:52pm

Chemistry
At a certain temperature, the Kp for the decomposition of H2S is 0.774. H2S(g) <---> H2(g)+S(g) Initially, only H2S is present at a pressure of 0.120 atm in a closed container. What is the total pressure in the container at equilibrium?
Tuesday, November 26, 2013 at 6:22pm

chemistry
2. What is the percent yield of Mg3N2 if 73.9 g of Mg reacts with 31.6 g of N2 to produce 79 g of Mg3N2 according to the following chemical reaction? (Reaction may or may not be balanced.) mg+n2=Mg3N2
Tuesday, November 26, 2013 at 6:06pm

chemistry
what is the OH of a 0.025 M HF solution?
Tuesday, November 26, 2013 at 12:37pm

Chemistry
(a) Which of the following are requirements for anionic polymerization? 1-A double bond 2- End groups which can react by releasing a small molecule 3- A strong base to initiate the reaction 4- A strong acid to initiate the reaction 5- An electron-withdrawing group near the ...
Tuesday, November 26, 2013 at 11:57am

Chemistry
The surface tension versus log concentration for two surfactants is shown below. Describe in no more than five sentences how the two surfactants can be so different. You have only one attempt at this problem. People from Edx what is the answer for this question..I'm asking...
Tuesday, November 26, 2013 at 6:43am

Chemistry 12
Given the following [H3O+] or [OH-] and the concentration of the solution calculate the dissociation constant, Ka. [OH-] = 3.9 x 10^(-9) M, with a concentration of 0.50M Answer:1.3 x 10^(-11) How do I get this answer?
Tuesday, November 26, 2013 at 1:49am

chemistry
what is another way you could determine the enthalpy of formation of magnesium oxide beside the experimental method?
Monday, November 25, 2013 at 11:03pm

chemistry (Dr.Bob222)
Do serial dilutions start out as saturated solutions?, Meaning when it starts out ppt forms, but there is a point where ppt stops forming, so when the ppt stops forming does that mean it is representing a saturated solution, and that when the ppt is not forming the solution ...
Monday, November 25, 2013 at 10:40pm

Chemistry
H(f) Cl= 121.3 kj H(f) C= 716.7 H(f) CCl4= -95.7 calculate the average molar bond enthalpy of the carbon-chlorine bond in a CCl4 molecule. I have tried to figure it out and keep getting the wrong answer. Please help!
Monday, November 25, 2013 at 10:05pm

chemistry
predict the reaction, if any, that would occur if AgNo3 and KBr were mixed would any reaction occur if HBr was then added?
Monday, November 25, 2013 at 9:05pm

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