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April 26, 2015

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
calculate the mass of Pbl2 produced by reacting of 30.0g Kl with excess Pb( NO3)2
Thursday, January 15, 2015 at 3:34pm

Chemistry
Which substance would have the highest melting point, based on electronegativity? H2S H2O H2Se H2Te H20? Hydrogen bonds can be found between molecules of which of the following substances? HI CH4 H2 NH3 not sure
Thursday, January 15, 2015 at 7:43am

chemistry
10g of hydrogen is burnt in the presence of excess oxygen.the mass of water formed is?
Thursday, January 15, 2015 at 6:37am

Chemistry
If a 10K race is 10.0 kilometers (1.00 × 10^4 meters), what is the distance in yards? (Given: 1 meter = 1.09 yards)
Wednesday, January 14, 2015 at 9:55pm

Chemistry
How many grams of solid product should form if 4.90 grams of sodium phosphate is mixed with 25 ml of .875M barium nitrate?
Wednesday, January 14, 2015 at 8:58pm

Chemistry
#6 If 10.0 grams of Aluminum carbonate(s) decomposes to produce aluminum oxide(s) and carbon dioxide(g), how many grams of CO2(g) are formed? If 5.00 grams is recovered experimentally what is the percent yield?
Wednesday, January 14, 2015 at 8:45pm

Chemistry
a solution of HCL is approximately 0.1M and has to be standardized . 1.234g Na2CO3 are dissolved to make 100ml of solution. 20mL of this solution are titrated with the HCL solution, requiring 31.3mL for the second equivalence point. what is the exact concentration of the HCL ...
Wednesday, January 14, 2015 at 8:12pm

Chemistry
Draw the pH-titration curve for the following, label x and y axes accordingly. 10 mL of 0.1M H3PO4 with 0.1 M NaOH (Logk values = 2, 7, 12) I understand that the x-axis is mL of H3PO4 added and y-axis is the pH. But the logK values, is that the equiv-points for the tri-protic ...
Wednesday, January 14, 2015 at 8:05pm

chemistry
A 5.0 L sample of nitrogen gas has a pressure of 95 kpa. What is the final volume of the gas if the pressure is tripled? I know p1 = 95, v1=5.0 and p2 = tripled What i dont understand is what number is tripled, is it 95 times 3??
Wednesday, January 14, 2015 at 7:32pm

Chemistry
A gas occupies 30 0dm3 at stp what volume would it occupy at 91 and 380mm hg?
Wednesday, January 14, 2015 at 6:10pm

Chemistry
#5 Limiting Reactants How many grams of water will be produced in the complete combustion of 20.0 grams of Octane, C8H18(g) and 50.0 grams Oxygen gas?
Wednesday, January 14, 2015 at 1:06am

chemistry
A sample of oxygen at 24.0 degrees celcius and 99.3 kpa was found to have a volume of 455 ml. How many grams of O2 were in the sample?
Tuesday, January 13, 2015 at 8:25pm

Chemistry
The overall reaction in a commercial heat pack can be represented as shown below. 4 Fe(s) + 3 O2(g) 2 Fe2O3(s) ΔH = -1652 kJ How much heat is released when 4.00 mol iron is reacted with excess O2? How much heat is released when 1.00 mol Fe2O3 is produced? How much heat is...
Tuesday, January 13, 2015 at 7:28pm

Chemistry
Write the reduction half reaction for the redox reaction below. ClO-(aq) + I-(aq) => Cl-(aq) + I2(s) Is I- being reduced since Cl is losing an O?
Tuesday, January 13, 2015 at 6:27pm

Chemistry
A 10.00mL sample of 0.02141mol/L potassium iodate was treated with excess iodide ion and titrated with sodium thiosulfate. If 32.33 mL of a Na2S2O3 solution was requried to reach the colorless endpoint (after addition of starch indicator) , what molarity of the Na2S2O3 ...
Tuesday, January 13, 2015 at 5:10pm

chemistry
The percentage yield for the reaction PCL3+Cl2-->PCL5 is 83.2%. What mass of PCL5 is expected from the reaction of 73.7g of PCL3 with excess chlorine?
Tuesday, January 13, 2015 at 4:19pm

Chemistry
Write the balanced half reaction for the reduction and oxidation reactions for the redox reaction: 2 Mg (s) + O2 (g) -> 2 MgO (s) Notice: for this question you do not have to include a charge of zero and you do not have to include the states. Below is an example of the form...
Tuesday, January 13, 2015 at 9:36am

chemistry
I want to boil 25c, 50c, and 75c to 100c but I don't have a thermometer. I did 0c which was 1.42 but I can't do the others.
Tuesday, January 13, 2015 at 2:46am

Chemistry (Chromatography)
Comment on the order of elution of the following solutes in (a) normal phase and (b) reversed phase liquid chromatography. Give reasons why. Solute X - non-polar Solute Y- Polar, a dipole Solute Z - Polar, more polar than solute Y I understand that polarity is the reason of ...
Tuesday, January 13, 2015 at 2:15am

Chemistry (Chromatography)
In elution chromatography (Ion-exchange) outline the order of elution for the following cationic species: Cu2+, Fe3+, Ag+ and Na+? I understand it has to do with polarity, but in which sense i.e does the least polar/most polar species elute first? Thanks
Tuesday, January 13, 2015 at 1:59am

Chemistry
#6. If 10.0g of Aluminum carbonate(s) decomposes to produce aluminum oxide(s) and carbon dioxide(g), how many grams of CO2(g) are formed? If 5.00g is recovered experimentally what is the % yield?
Tuesday, January 13, 2015 at 12:20am

Chemistry
How many grams of water will be produced in the complete combustion of 20.0g of Octane, C8H18(g) and 50.0g Oxygen gas?
Tuesday, January 13, 2015 at 12:14am

Chemistry
How many grams of water are produced when 10.0g of Butane, C4H10(g) completely combust with 2.50 moles of Oxygen gas?
Tuesday, January 13, 2015 at 12:12am

Chemistry
A strip of zinc medal weighing 2.00 grams is placed in an aqueous solution containing 150.ml of .750M Tin(II) nitrate. Determine the grams of tin metal that will be precipitated.
Tuesday, January 13, 2015 at 12:10am

Chemistry
Lead(II) carbonate decomposes to form Lead(II) oxide and carbon dioxide. If 5.oo grams of the reactant decomposes to produce 1.52 grams of Lead(II) oxide experimentally, what is the theoretical yield and percent yield.
Tuesday, January 13, 2015 at 12:08am

chemistry
The molarity of a kool-aid packet is 0.365M. How many grams of sucrose (C12H22O11) are in 200mL of the kool-aid drink? --- I know that the molar mass is 342.29648 g/mol kool-aid. I'm not sure on how to find the grams of the solute.
Monday, January 12, 2015 at 10:51pm

Chemistry
HAve to find a formula to work out the energy required to thermally decompose water into hydrogen and oxygen.
Monday, January 12, 2015 at 9:56pm

Chemistry
2Mg(s) + O2(g) 2MgO(s) If 9.92 g of Mg reacts with 8.52 g of O2. How many grams of MgO could be produced? I am just very confused and need an answer so that I can look back on how you got there . . .
Monday, January 12, 2015 at 9:50pm

Chemistry
As a purity check for industrial diamonds, a 22 - carat diamond (1 carat = 0.2g) is heated to 63 degrees C and immersed in 26g of water in a constant pressure calorimeter. The initial temperature of the water is 23 degrees C. Calculate the ΔT of the water and of the ...
Monday, January 12, 2015 at 8:01pm

chemistry Drbobz222
How do i convert mols CaCl2 to AgCl
Monday, January 12, 2015 at 7:38pm

Chemistry
if 50 grams of sodium hydroxide mixed with 25 grams of hydrochloric acid how many grams of salt can be formed?
Monday, January 12, 2015 at 7:29pm

chemistry check my answer
In an acid base titration 32.5 ml of sodium hydroxide were neautralized by 17.6 ml of 0.180 mol/l sulfuric acid. Calculate the concentration of the sodium hydroxide. I asked this question earlier but i wanted to make sure i got the right answer My answer: 0.36 mol/L is this ...
Monday, January 12, 2015 at 7:20pm

Chemistry
2C2H2(g) + 3O2(g) 4CO(g) + 2H2O(g) What is delta G° for this reaction in J/mol? (T = 298.17 K)
Monday, January 12, 2015 at 7:01pm

chemistry am i right
Balance and complete equation H2SO4 + Na2CO3 ---> Na2SO4 + H2O + CO2
Monday, January 12, 2015 at 6:55pm

chemistry
What mass of precipitate is formed when 0.750 L of 2.50 mol/L CaCl2 reacts with 650 mL of 1.75 mol/L AgNO3
Monday, January 12, 2015 at 6:49pm

chemistry
What volume of 1.34 mol/L hydrochloric acid, HCI is expected to react completely with 6.89 g of calcium
Monday, January 12, 2015 at 6:04pm

chemistry
The ionic equation and net ionic equation and balance equation: A) Ca(OH)2 + HNO3 --> B) H2SO4 + Na2CO3 --->
Monday, January 12, 2015 at 6:03pm

Chemistry
Calculate the heat transferred when a 23 g of iron nail is cooled from 67oC to 20oC. The specific heat of iron is 0.45 J/goC.
Monday, January 12, 2015 at 5:57pm

Chemistry
A skillet made of Iron (Fe) weighing 1.8 kg is heated on a stove to a temperature of 202 degrees C. If the skillet is removed from the stove and allowed to cool to room temperature (21 degrees C), how much heat must be removed from the skillet. The specific heat of Iron is 0....
Monday, January 12, 2015 at 5:56pm

chemistry
A 0.248 M ZnCO3 solution is made from 21.4 g of solute? What is the volume of the solution?
Monday, January 12, 2015 at 5:46pm

chemistry
What volume of 1.34 mol/L hydrochloric acid, HCI, is expected to react completely with 6.89 g of calcium?
Monday, January 12, 2015 at 5:28pm

chemistry
Write a balanced equation, ionic equation and the net ionic equation for the following: A) Li2SO4 + Sr(NO3)3 ---> B) H2SO4 + Na2CO3 --->
Monday, January 12, 2015 at 5:06pm

chemistry
In an acid base titration,25.0 ml of nitric acid, HNO3, were neautralized by 28.0 mL of 0.209 mol/L calcium hydroxide, Ca(OH)2. What is the concentration of the nitric acid?
Monday, January 12, 2015 at 4:53pm

Chemistry
In an acid base titration 32.5 mL of sodium hydroxide, NaOH, were neutralized by 17.6 mL of 0.180 mol/L sulfuric acid, H2SO4. Calculate the concentration of the sodium hydroxide.
Monday, January 12, 2015 at 4:50pm

Chemistry
When a chemist burns ammonia according to the reaction below she finds that the reaction releases heat. (It is exothermic.) 4NH3(g) + 3O2(g) 2N2(g) + 6H2O(g) The enthalpy of the reaction DH = -1267 kJ. What is the enthalpy change (in kJ) when 7 grams of ammonia are burned?
Monday, January 12, 2015 at 4:42pm

Chemistry
Calculate the total heat (in Joules) needed to convert 1.602 x 101 grams of ice at -1.383oC to liquid water at 8.554 x 101oC. Melting point at 1 atm 0.0oC Cwater(s) = 2.09 J/goC Cwater(l) = 4.18 J/goC delta Hofus = 6.02 kJ/mol
Monday, January 12, 2015 at 4:41pm

Chemistry
1.984 g of a hydrate of K2CO3 is dissolved in 250. mLs of H2O. 10.0 mLs of this solution is tirade against 0.100 M HCl, producing the following results. Flask 1 - Initial 0, final 9.2 Flask 2 - Initial 9.2, final 18.3 Flask 3 - initial 18.3, final 27.8 Flask 4 - initial 27.8, ...
Monday, January 12, 2015 at 3:59pm

chemistry
i have a homework packet that i am struggling with can you please help me my first question is i have to finish the following equation to balance it out my question is 3Fe3O4+blankAl→blankAl2O3+blankFe now i tried and i got 3Fe3O4+2A=2Al2O3+2Fe i dont know if thats right...
Monday, January 12, 2015 at 12:59pm

Chemistry
Calculate the pH and pOH of a hydrochloric acid solution prepared by dissolving 30.50-kg of hydrogen chloride gas in 806-L of water at SATP.
Monday, January 12, 2015 at 12:08pm

ap chemistry
how do you find the mass of dehydrated sample? mass of crucible and cover- 30.95 g mass of hydrated sample, crucible, and cover- 32.75 g mass of hydrated sample-? mass of dehydrated sample, crucible and cover- 1st weighing-32.47 g mass of dehydrated sample, crucible, and cover...
Monday, January 12, 2015 at 11:13am

chemistry
how many HCl needed to dissolve 1 grams of Al2O3.
Monday, January 12, 2015 at 5:39am

chemistry exercises
The concentrated H2SO4 of 155g dissolved in enough amount of water if acidic solution is 2.3L a) what is the mole of H2SO4 b) what is the concentration H2SO4 c) what is the concentration of H+(H3O+) created in the solution d) what is the PH value of solution e) what is the ...
Monday, January 12, 2015 at 4:14am

chemistry
2) At 298K, what are the molarities of pure water?
Monday, January 12, 2015 at 4:08am

chemistry
The concentrated H2SO4 of 155g dissolved in enough amount of water if acidic solution is 2.3L a) what is the mole of H2SO4 b) what is the concentration H2SO4 c) what is the concentration of H+(H3O+) created in the solution d) what is the PH value of solution e) what is the ...
Monday, January 12, 2015 at 4:03am

Chemistry (Acid-Base)
I'm a tad confused by the question, The protonation constant for the acid HA has the value K=2*10^6. (a) what is the principal species at pH 6.00? (b) what is the principal species at pH 9.00? (c) what is the quotient [A-]/[HA] at pH 6.3 and 7.5?
Monday, January 12, 2015 at 12:19am

chemistry
What number of aluminum atoms are in a 65.8g sample of Aluminum Oxide?
Sunday, January 11, 2015 at 11:55pm

Chemistry
How many atoms of iron will be produced from the reaction of 50 g of hematite and 25 g of carbon?
Sunday, January 11, 2015 at 11:29pm

chemistry college
At a constant temperature of 20oC and the partial pressure of 760 mmHg, the solubility of CO2 in water is 0.169g per 100mL. If the partial pressure is changed to 43,000 mmHg, what is the solubility of CO2?
Sunday, January 11, 2015 at 10:57pm

Chemistry
An EDTA solution is standardised against high-purity CaCO3 by dissolving 0.4835 g CaCO3 in HCl, adjusting the pH to 10 with ammoniacal buffer and titrated with an EDTA solution. If 35.18ml were required for the titration, what was the molarity of the EDTA solution? Step 1. ...
Sunday, January 11, 2015 at 10:46pm

Chemistry
Mercury and bromine will react with each other to produce mercuric bromide. What mass of mercuric bromide can be produced from the reaction of 5.00 mL mercury (density 13.5 g/mL) and 5.00 mL bromine (density 3.2 g/mL)? What volume in mL of excess reactant remains?
Sunday, January 11, 2015 at 10:34pm

Chemistry
What are the ppm of each of the atoms contained in a solution that is 655 ppm K3PO4?
Sunday, January 11, 2015 at 9:37pm

chemistry
what quantity of ice would be melted by 2.80 x 10^3 calorie of heat.
Sunday, January 11, 2015 at 9:09pm

Chemistry
If an electric discharge produces 800 cm3 of ozone (O3), how many cm3 of oxygen (O2) are required? 3O2(g) ---> 2O3(g)
Sunday, January 11, 2015 at 7:48pm

chemistry
For the formation of ammonia, the equilibrium constant is known to be 5.2 × 10−5 at 25◦C. After analysis, it is determined that [N2] = 3.1 M and [H2] = 0.8 M, both at equilibrium. How many grams of ammonia are in the 10 L reaction vessel at equilibium? Use ...
Sunday, January 11, 2015 at 7:47pm

CHEMISTRY
A 1.000 L vessel is filled with 2.000 moles of N2, 1.000 mole of H2, and 2.000 moles of NH3. When the reaction N2(g) + 3 H2(g) ⇀↽ 2 NH3(g) comes to equilibrium, it is observed that the concentration of H2 is 2.53 moles/L. What is the numerical value of the ...
Sunday, January 11, 2015 at 7:44pm

Chemistry
I have two questions that I do not know how to answer. Thanks for your help! 1. Calculate the [OH^-], [H^+], pH, and pOH for a 0.50M solution of CN^- 2. Calculate the molar solubility of PbCl2 in 0.40M KCl
Sunday, January 11, 2015 at 7:03pm

chemistry
if the average concentration of PCBs in the body tissue of a human is 4.0 ppm, what mass of the PCB is present in a 64 kg person? is this a significant amount in regards to the health of the person? What is the concentration of a solution of sodium nitrate that contains 35.0 g...
Sunday, January 11, 2015 at 6:57pm

chemistry
if the average concentration of PCBs in the body tissue of a human is 4.0 ppm, what mass of the PCB is present in a 64 kg person? is this a significant amount in regards to the health of the person? What is the concentration of a solution of sodium nitrate that contains 35.0 g...
Sunday, January 11, 2015 at 6:47pm

chemistry
What volume of 0.20M NaOH will contain 1.00g of NaOH
Sunday, January 11, 2015 at 6:18pm

Chemistry
Mercury and bromine will react with each other to produce mercuric bromide. What mass of mercuric bromide can be produced from the reaction of 5.00 mL mercury (density 13.5 g/mL) and 5.00 mL bromine (density 3.2 g/mL)? What volume in mL of excess reactant remains?
Sunday, January 11, 2015 at 5:03pm

Chemistry
What is the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29.0% oxygen? -I found this to be C3H3O and WebAssign says it's right. I need help with part b. If the molar mass of the above compound is 110 grams/mole, what is the molecular formula?
Sunday, January 11, 2015 at 4:51pm

Chemistry
How many mL of 0.5 M HCl(aq) are needed to neutralize a 288 mL solution of 0.25 M NaOH?
Sunday, January 11, 2015 at 4:12pm

Chemistry
The following questions relate to the chemical equation shown below. Since this is a multi-stage question, be sure to write down the balanced equation and the values for deltaHo and deltaSo before proceeding. A2(g) + 3 B2(g) → 2 AB3(g) deltaHo = -217 kJ mol-1 deltaSo = -...
Sunday, January 11, 2015 at 4:05pm

Chemistry
Part 1 of 2 Write the balanced molecular equation for the reaction between iron metal (the nail) and aqueous copper II sulfate and classify this reaction. Include the states: solid (s), liquid (l), aqueous (aq), or gas (g). Use your observations to help you determine the ...
Sunday, January 11, 2015 at 3:42pm

Chemistry
find the mass in grams of 1.40x10^23 molecules of n2
Sunday, January 11, 2015 at 3:37pm

Chemistry
A current of 4.00 A is passed through a solution of AgNO3 for 1.00 hr. What mass of silver is deposited at the cathode? (In grams) Use Faraday's constant F = 9.65x10^4 C/mol
Sunday, January 11, 2015 at 3:27pm

chemistry
Determine themass of the copper solid produced when excess magnessuim metal reacts with 250 ml of 0.0500M copper acetate solution. if 6.00g of copper was recovered experimentally determine the percent yeild. Thank you in advance.
Sunday, January 11, 2015 at 2:54pm

Chemistry
Calculate the pH of a solution prepared by diluting 0.0015L of a 0.100 mol/L nitric acid solution with 0.5L of water. *C1×V1=C2×V2 C2=0.3MOL/L Do we use this concentration to find the pH
Sunday, January 11, 2015 at 1:59pm

Chemistry
How long (in seconds) does it take to deposit 1.065e+001 g Zn on a steel gate when 2.375e+001 A are passed through a ZnSO4 solution?
Sunday, January 11, 2015 at 1:42pm

Chemistry
A cell exhibits a standard Ecell of 0.35V at 298K. What is the value of the equilibrium constant for the cell reaction if n = 2?
Sunday, January 11, 2015 at 1:41pm

chemistry
Sulfuric acid is dripped onto samples of three metals: silver, =zinc, and aluminium a) Use the activity series to determine whether a reaction will occur with each metal b) Write a chemical equation for each reaction that occurs
Sunday, January 11, 2015 at 1:28pm

chemistry
How much heat is lost when 12.55 g of zinc vapor at 907 degrees celsius is cooled to 425 degrees celsius?
Sunday, January 11, 2015 at 12:49pm

Chemistry
The reaction of sodium hydrogen carbonate (baking soda), NaHCO3 and vinegar is a safe and effective method of opening a clogged drain a) Write the chemical equation for this reaction b) Explain why using sodium hydrogen carbonate and vinegar may be a greater alternative to ...
Sunday, January 11, 2015 at 12:38pm

Chemistry
Write the total ionic and net ionic equations for each of the following reactions: A) hydrobromic acid with potassium hydroxide B) Nitric acid with barium hydroxide
Sunday, January 11, 2015 at 12:23pm

ap chemistry
glycerin C3H8O is a nonvolatile liquid. what is the vapor pressure of a solution made by adding 164 g of glycerin to 338 mL of H2O at 39.8C. The vapor pressure of pure water at 39.8C is 54.74 torr and its density is 0.992 g/cm3 P solution= X solvent p solvent 1.78g C3H8O3
Sunday, January 11, 2015 at 11:37am

chemistry
did i answer the question: Explain how one of the major concepts learned in CHM 111 applies to everyday life. One major concept that was learned in CHM 111 that applies to everyday life is stoichiometry. Stoichiometry is founded on the law of conservation of mass where the ...
Sunday, January 11, 2015 at 11:32am

chemistry
What is brownian motionand example
Sunday, January 11, 2015 at 9:58am

chemistry
amount of sugar present in 250g of 15% aqueous sugar solution (w/w) is ?
Sunday, January 11, 2015 at 9:47am

chemistry
Determine the mass of the precipitate, lead iodide that is formed when 150 ml of 0.0500M pb(no3)2 is reacted with excess potassium iodide. if 3.3 of the precipitate is experimentally recovered, determine the percent yeild.
Sunday, January 11, 2015 at 2:33am

chemistry
Classify each substance as either arrhenius acid or base: A) HF (aq) B) Ba(OH)2 (aq) C) H2SO4 (aq) D) NH4OH (aq) My work A) arrehenius acid B) arrhenius base C) arrhenius acid D) arrhenius base Am i right
Saturday, January 10, 2015 at 11:35pm

Chemistry-Paramagnetic or Diamagnetic
I did a lab where I was supposed to make "estimates" on transition compounds based on their electron configuration of how the compounds will react positively or negatively and then to experiment the compounds in conjunction with the strong magnets to evaluate their ...
Saturday, January 10, 2015 at 10:08pm

Chemistry
What is the mass of 1.00 mol of sodium hydrogen carbonate?
Saturday, January 10, 2015 at 7:52pm

Chemistry
What is the percent by mass of hydrogen in aspirin C2H8O4?
Saturday, January 10, 2015 at 7:50pm

ap chemistry
did i answer the question: Explain how one of the major concepts learned in CHM 111 applies to everyday life. One major concept that was learned in CHM 111 that applies to everyday life is stoichiometry. Stoichiometry is founded on the law of conservation of mass where the ...
Saturday, January 10, 2015 at 7:38pm

Chemistry grade 11
An organic compound is composed of C, H and O. A 0.1005 g sample of this is combusted, producing 0.2829 g CO2 and 0.1159 g of H2O. What is the empirical formula of this compound? If the compound has a molar mass of 14 g/mol. What is the molecular formula?
Saturday, January 10, 2015 at 6:58pm

Chemistry
In a constant-pressure calorimeter, 50.0 mL of 0.320 M Ba(OH)2 was added to 50.0 mL of 0.640 M HCl. The reaction caused the temperature of the solution to rise from 21.80 °C to 26.16 °C. If the solution has the same density and specific heat as water, what is ΔH ...
Saturday, January 10, 2015 at 5:18pm

Chemistry
If 0.45 M of ammonia solution has a pH of 9.20, what is the H+ concentration of the solution?
Saturday, January 10, 2015 at 5:15pm

Chemistry.
Give the empirical formula of each of the following compounds if a sample contains the following quantities of each element. (a) 0.0091 mol C, 0.0186 mol H, and 0.0045 mol O Please show me how to do this. My notes are very confusing and I don't know how to apply them to ...
Saturday, January 10, 2015 at 3:37pm

chemistry
what major concepts makes chemistry useful in everday life?
Saturday, January 10, 2015 at 2:38pm

ap chemistry
how do you determine the number of waters of hydration per formula unit? the general formula
Saturday, January 10, 2015 at 2:13pm

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