Most popular questions and responses by Chem
  1. chemistry

    Nylon 88 is made from the monomers H2N(CH2)8NH2  and  HOOC(CH2)6COOH.  So, would you characterize nylon 88 as rather an addition or a condensation polymer? Please explain your answer

    asked on July 24, 2016
  2. Chemistry

    carbon dioxide dissolves in water to form carbonic acid. Estimate the thermodynamic equilibrium constanst (K) for this reaction (delta Gf values: H2CO3= - 616.1, H2O= - 237.1, CO2= - 394.4) . Carbonic acid then ionizes in water (Ka1= 4.5 x 10^-7). Ignoring

    asked on March 21, 2014
  3. Ochem

    What volume of eugenol will be present in 30 mL of distillate? The essential oil found in cloves, eugenol, can be isolated by steam distillation because it is insoluble in water and has a measurable vapor pressure at 100 °C even though it has a much

    asked on August 4, 2014
  4. Chemistry

    Sucrose hydrolyzes into glucose and fructose. The hydrolysis is a first order reaction. the half life for the hydrolysis of sucrose is 64.2min at 25C. How many grams fo sucrose in 1.25L of a 0.389M solution are hydrolyzed in 1.73hrs? I started off by

    asked on December 25, 2010
  5. Enthalpy of Formation

    N2H4(g) + H2(g)--> 2 NH3(g) H1 = –1876kJ 3 H2(g) + N2(g)--> 2 NH3(g) H2 = –922 kJ The H.f for the formation of hydrazine: 2 H2(g) + N2(g)--> N2H4(g) will be______kj/mol I am very confused here. I thought I would just add H1 and H2 and divide by the

    asked on May 16, 2010
  6. Organic chemistry

    How many grams of water would it take to quench 1 g of phenylmagnesium bromide?

    asked on February 12, 2010
  7. 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

    asked on April 3, 2015
  8. chem help

    Ammonia,is a weak base with a Ka value of 1.8x10^-5 .What is the pH of a 0.22M ammonia solution?

    asked on February 28, 2009
  9. 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.

    asked on April 3, 2015
  10. Chemistry

    Explain the function of the aluminum wire and the mercury II chloride when testing for tin? when testing for antimony, what reagent prevents tin from reacting with the H2S to form SnS2? What reagent is used to identify copper and explain its function.

    asked on October 16, 2011
  11. Madison

    From the molecular equation find the overall ionic and net ionic: Molecular: H3PO4 (aq) + 3NaOH (aq) --> Na3PO4 (aq) + 3H2O (l)

    asked on March 8, 2019
  12. Chemistry

    What is the molarity of the final solution if 2.00mL of the 5.00 M stock solution is diluted to 10.00mL to make solution A? Solution A then undergoes a second dilution by taking 3.00mL solution A and diluting it to 25mL.

    asked on November 15, 2016
  13. 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.

    asked on April 3, 2015
  14. science

    An excess of aluminum metal is added to 200.0 mL of 0.025 M solution of CuCl2, reducing the Cu+2 ions to metallic Cu. If the temperature of the solution increases from 25.0 to 27.5 degrees celsius, what is the enthalpy of this reaction per mole of Cu

    asked on December 29, 2010
  15. chem

    How to find the %(W/V) of 134mL of a 0.610 M solution of Mg(OH)2

    asked on February 16, 2012
  16. Chemistry

    1) How many drops of 12M HCl would you add to 1.00 L of 0.100 M HC2H3O2 to make [C2H3O2-] = 1.0 x 10^-4 M? Assume that 1 drop = 0.050 mL and that the volume of the solution remains 1.00 L after the 12 M HCl is diluted. [Hint: What must be the [H3O+] in the

    asked on August 10, 2009
  17. 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

    asked on April 3, 2015
  18. Chemistry

    Discuss how your supernatant color in the 6 different test tubes supports your calculated result in #2. For example, if you used less than the volume of sodium phosphate calculated in #2, what would be the limiting reactant and does the observed

    asked on March 1, 2015
  19. chemistry

    On complete oxidation, one mole of an organic compound produced four moles of water. Which one of the following substances could it be? CH4 C2H6 C3H7OH C4H10 So I added O2 to each of these compounds, but I must be doing something wrong because I can't get

    asked on December 28, 2010
  20. Chemistry

    A hot air balloon is filled with hot air and the hot air forces the volume of the balloon to expand until the density of the gas in the balloon is less than the density of the outside air. The volume must be 20% larger than the balloon would be at STP in

    asked on April 25, 2016
  21. Dan

    N2 + 3H2 --> 2NH3 At 25°C (delta)Ho = -92.22 kJ and (delta)So = -198.53 J/K. Using this information, calculate the equilibrium constant for the reaction at 2.43x10^2°C. (R = 8.314 J/K) Apparently the way I'm doing it is wrong: I divide 198.53 by 1000

    asked on November 17, 2007
  22. Intro Chemistry

    _______g of MnSO4 H2O are needed to prepare a solution of 100.00mL of 0.100 M MnSO4. Thank You

    asked on April 12, 2010
  23. Chemistry

    If we were to fill a bottle with boiling hot water than place it in a bucket filled with cold water what would happen to the bottle and why? i know the bottle would get crushed inwards but whats the science behind this can someone explain?

    asked on January 15, 2017
  24. chem!

    Calculate the heat of reaction for the incomplete combustion of 67.0g propane producing carbon monoxide gas and water vapour. how would I go about and do this question? What are you studying? Do you know how to use the thermodynamic tables (delta Ho, etc).

    asked on May 14, 2007
  25. chemistry

    How much pure calcium carbonate (100.09 g/mol) is required to produce 40.0 mL carbon dioxide gas according to the reaction used in this experiment? Your unknown will contain between 25-100% calcium carbonate. Answer to 3 significant figures. Do not include

    asked on November 8, 2015
  26. Chemistry

    Using the "octet rule" write the Lewis formulas for NF3 and NO3-.

    asked on February 22, 2012
  27. chemistry equilibriums

    At a certain temperature, 2.00 moles of phosphorus(V) chloride, PCl5, was placed in a 1.0 L vessel and permitted to react as shown: PCl5 (g) PCl3 (g) + Cl2(g) At equilibrium, the container held 0.40 PCl5. What is the numerical value of Kc for the system as

    asked on December 29, 2010
  28. chem lab

    hi im doing a post lab sheet for chem class. and im having a little trouble. i have: temperature 12.6 C -> 285.6 K Time 816 sec but im supposed to find 1/T(K) it looks like my classmate did this: 12.6 x 285.6 = 3598.56 however they gave me the response to

    asked on October 16, 2010
  29. gen chem

    At 2273K, equilibrium constant for the reaction 2NO(g)N2(g)+O2(g) Kc=2.4x10^3 What would be equilibrim concentration of N2, if initial concentration of NO was 0.1160M?

    asked on May 9, 2010
  30. gen chem

    what would Qc be if the pressure of the container decreased by a factor of 2.417 for the following reaction? 4Hcl(g)+O2(g)2Cl2(g)+2H2O(g) Kc=13.298 @ 753K

    asked on May 9, 2010
  31. gen hem

    what is the free energy change in kJ for the reaction below? 2NO3-(aq)+8H+(aq)+3Hg(l) 2NO(g)+4H2O(l)+3Hg2+(aq) E0=0.106V

    asked on May 8, 2010
  32. chem help

    You need to produce a buffer solution that has a pH of 5.08. You already have a solution that contains 10 mmol (millimoles) of acetic acid. How many millimoles of acetate (the conjugate base of acetic acid) will you need to add to this solution? The of

    asked on February 28, 2009
  33. CheMistry

    A stock solution was prepared by dissolving exactly 0.4000 g of pure ASA (180.16 g/mol) in 10.00 mL of NaOH and heating the solution to a gentle boil. After cooling to room temperature, the solution was poured into a 250-mL volumetric flask and diluted to

    asked on April 18, 2010
  34. Chem

    4.30 grams of NH4Cl is added to 14.5 grams of water. Calculate the molality of the solution

    asked on January 20, 2014
  35. gen chem

    if the voltage of the cell is 2.0898V at 25C when [Mg2+] = 0.1945M and the pressure of H2 = 1.00atm, what is the pH? E0=2.3700V Mg(s)+2H+(aq) Mg2+(aq)+ H2(g)

    asked on May 8, 2010
  36. 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

    asked on April 3, 2015
  37. Chemistry

    When weighing liquid ethanol, why do you have to place water in the beaker prior to adding the ethanol to that same beaker?

    asked on November 24, 2013
  38. chemistry

    How much energy (in kilojoules) is released when 21.0 of ethanol vapor at 94.5 is cooled to -19.0?

    asked on September 12, 2011
  39. chem

    Calculate the volume of 0.200 M acetic acid and the volume of 0.100 M sodium acetate required to make 200.0 mL of a buffer solution with pH = 5.00. The Ka for acetic acid at 298 K is 2.00 x 10-5.

    asked on April 4, 2011
  40. Unit Cells

    Copper has a unit cell volume of (47.453 A^3) and a face centered unit cell. How would I go about finding the volume of atoms within the unit cell? Would you use Avogadro's # somehow?

    asked on May 9, 2010
  41. PHySICS

    A rod 14.0 cm long is uniformly charged and has a total charge of -22.0 μC. Determine the magnitude and direction of the electric field along the axis of the rod at a point 36.0 cm from its center. ans:E = 1.59e6 N/C, pointing to the left

    asked on April 13, 2010
  42. chemistry

    Which of the following subshells is correctly designated? a. 1f5 b. 3s3 c. 6f12 d. 4d11 e. 1p2

    asked on December 7, 2007
  43. CHEM

    A particular reactant decomposes with a half-life of 139 seconds when its initial concentration is 0.342 M. The same reactant decomposes with a half-life of 237 seconds when its initial concentration is 0.201. What is the value and unit for this rate

    asked on January 25, 2014
  44. Chemistry

    How do you draw a lewis dot structure of s3o

    asked on February 22, 2012
  45. Intro Chemistry

    I am reviewing my test and I having trouble figuring out the answer to the following question: List the following element symbols in order of decreasing exothermic electron affinity: Al, Ca, As _______>________>________ I wrote: Al>As>Ca (I got it wrong) I

    asked on March 6, 2010
  46. GenChem II

    What mass of CsBr must be added to .500L of water to produce .4molality solution? What are mole fraction and mass percent? Here is my work and below I will post a question about it: 1 mol CsBr = 212.81g density of water = 1g/mL d=mv 1=x/500 x=500g of water

    asked on February 18, 2010
  47. chemistry

    Consider a system consisting of a cylinder with a movable piston containing 10^6 gas molecules at 298K at a volume of 1L. Consider the following descriptions of this system: 1. Initial system 2. Starting from the initial system, the volume of the container

    asked on March 16, 2009
  48. chemistry

    0.947 moles of NaC2H3O2 dissolved in 100 mL solution

    asked on April 16, 2015
  49. Chemistry

    What is the pH of a 0.20 M HF solution that is 5.8% ionized at 25 Celsius ? A.4.45 b.0.70 C.1.93 D.1.23 E.1.40

    asked on March 19, 2013
  50. Chemistry

    In the laboratory exercise "Preperation and Properties of Polymers", polyvinyl alcohol is dissolved in water and then reacted with borax (Na2B4O7·10H2O) in water. Which of the following are expected results of this reaction? True or False? 1. Polyvinyl

    asked on April 22, 2011
  51. CHemiStry!

    Select all ionic compounds in which the number of anions present is two. carbon dioxide X manganese(II) hydroxide mercury(II) carbonate X mercury(II) phosphate ammonia sulfur dioxide Hello, I know manganese(II) hydroxide mercury(II) phosphate both have two

    asked on May 7, 2010

    calculate the pH of 0.0076M KOH

    asked on September 7, 2007
  53. chemistry

    Which one of the following complex ions has an optical isomer? a. [Zn(phen)2]2+ b. [Cu(CN)4]2– c. [Co(H2O)4en]2+ d. [Zn(NH3)2en]2+ e. [Ni(en)3]2+ how would i go about finding this answer? i don't need the answer give would prefer steps. thanks

    asked on October 8, 2016
  54. Chemistry

    Procedure 0) The sodium phosphate, Na3PO4 solution has NPFA ratings of 1 (out of 4) for health, 0 for fire, and 0 for reactivity. Cobalt (II) nitrate has 2 for health, 0 fire, and 0 for reactivity. 1) Carefully label (1-­‐6) and weigh 6 small test

    asked on March 1, 2015
  55. -

    What mass of Al can be deposited by the passage of a constant current of 5.00 A through a Al(NO3)2 solution of 2.00 hours? My work: Q= I*t = 5 * 7200sec = 36000 36000/96458= .3732 .3732* 1/3 * (26.98*3) = 10.06g But this is wrong it's suppose to be 3.3.6g.

    asked on August 9, 2009
  56. chemistry

    An aqueous solution contains 0.445 M ethylamine (C2H5NH2). How many mL of 0.226 M hydrochloric acid would have to be added to 150 mL of this solution in order to prepare a buffer with a pH of 10.200

    asked on March 16, 2015
  57. Chemistry

    Use your balanced equation to calculate the volume of 0.12 M Na3PO4 to stoichiometrically react with the 3.0 mL of Co (NO3)2. Show your work.

    asked on March 1, 2015
  58. Organic Chemistry

    Suggest structures for C10H14O; C10H16; C10H18; C10H16O3; C10H16O2 ; C12H22O2 in the following reaction schema: The UV/Visible spectrum for C10H14O exhibits a at 244 nm C10H16 + hot KMnO4 + H2SO4 → C10H16O3 C10H16O3 + Zn(Hg)/conc HCl → C10H18O2

    asked on April 6, 2011
  59. Organic Chemistry

    The UV/Visible spectrum for C10H14O exhibits a at 244 nm C10H16 + hot KMnO4 + H2SO4 → C10H16O3 C10H16O3 + Zn(Hg)/conc HCl → C10H18O2 C10H18O2 + CH3CH2OH + H3O+ → C10H22O2

    asked on April 6, 2011
  60. chem: study of kinetics

    im supposed to find the slope= -EA/R = triangle y/triangle x = (y2-y1) ________/(x2-x1)____________ how do i do this? is it the same as the slope that excel gave me? i have information from 3 different groups, and i have 3 x's and 3 y's, how do i solve

    asked on October 16, 2010
  61. gen chem

    what is the pK (=-logK)at 25C for the reaction below? Cl2(g)+6H2O(l)+5Cu2+(aq)2ClO3-(aq)+12H+(aq)+5Cu(s) E0=-1.133V

    asked on May 8, 2010
  62. gen chem

    what must be the current in amperes to plate out 7.437g of Al from am aqueous solution of Al3+ in 5.4x10^2 minutes?

    asked on May 8, 2010
  63. college Chemistry

    If [K+] inside a cell is 25 times greater than a [K+] outside the cell, what is the difference in potential between the two sides of the cell wall? (this is a "concentration cell" style of problem)

    asked on May 1, 2010
  64. chemistry

    Which of the following subshells is correctly designated? a. 1f5 b. 3s3 c. 6f12 d. 4d11 e. 1p2

    asked on December 7, 2007

    calculate the pOH of 3X106-6M of HF

    asked on September 7, 2007
  66. sciaece

    titration of sodium hydroxide with tetraoxosulphate4 acid.

    asked on April 27, 2017
  67. chemistry

    When performing an extraction, is it better to have a higher or lower K (distribution coeffictient/ partition coefficient) value? Explain.

    asked on October 30, 2016
  68. chemistry

    Which of the following statements describes why ion exchange of 99% SiO2 - 1% B2O3 in a salt bath of molten postassium chloride (KCl) is not an effective way to increase the surface strength of the glass sample? The ion exchange works correctly, however

    asked on November 1, 2013
  69. Stela

    CCl4 ClO4− ClF4− SiCl4 SO42− Which molecule or ion does not have a tetrahedral molecular geometry?

    asked on October 25, 2012
  70. Chemistry

    True/False 1. Diatomic molecules contain two atoms?T 2. Electrons travel in pairs? T 3. The energies needed to break chemical bonds can be measured T 4. Bonding involves all the electrons in an atom T 5. Lewis structures are used to describe bonding? F 6.

    asked on January 16, 2011
  71. Molarity/molality

    A 3.29 m solution of the solute H2O dissolved in the solvent acetone is available. Calculate the mass ( kg ) of the solution that must be taken to obtain 26.70 mol of H2O. m= molality I have no idea how to approach this problem, I'm not interesting in

    asked on May 7, 2010
  72. Chemistry

    what would the freezing point be for a solution of 0.87M aqueous ammonia? The density of this solution is 0.992g/cm3

    asked on May 3, 2010
  73. Hydrogen Bonding

    The longer the hydrogen bond, do the Intermolecular Forces increase or decrease. So if molecule A has a H-bond with a length of 1.7 A and molecule B has a H-bond length of 1.8 A would molecule A or molecule B have a stronger IMF? It would seem that the

    asked on May 3, 2010
  74. Chem

    complete and balance the following decompition equations CaCO (heated) --> 3 please tell me how to do this and what exactly is suppose to be going through my head while doing this. I can balance these equations with no problem I just have no idea what to

    asked on December 17, 2008
  75. Chemistry

    How many atoms are there in 6.90 moles of sulfur (S)? Calculate the molar mass of a compound if 0.411 mole of it has a mass of 185 g. Know of any good sites that help answer these ? Or information on how to?

    asked on September 15, 2008
  76. jessie

    hi im doing a post lab sheet for chem class. and im having a little trouble. we did an experiment where we put a mixture into a bath and checked to see how long a color would leave from the mixture. i have temperature 12.6 C -> 285.6 K Time 816 sec but im

    asked on October 15, 2010
  77. General Chemistry

    How much energy in kJ is realeased to form one mole of Cd 116(isotope) from protons and neutrons if the atom has a mass of 115.90476amu.

    asked on May 8, 2010
  78. Oxidation State

    Give the oxidation sate for the monoatomic cobalt species whose electron configuration is the following:[Ar]4s0 3d6 Is the answer +3? Thank you!

    asked on March 6, 2010
  79. chemistry

    Does the element sodium have properties in common with NaCl? Explain

    asked on February 11, 2008
  80. question

    whats relationship between temp and kinetic energy

    asked on March 7, 2007
  1. chemistry

    So what was the correct answer because i have no clue how to do this

    posted on February 3, 2018
  2. chemistry

    im not to sure what phen and en are short for. but im thinking the answers maybe d) if zinc is bonded to 2 (NH3) and if en means the rest of atoms its bonded to are the same.??

    posted on October 9, 2016

    100.016 or 1.00 x 10^2 kj/mol

    posted on May 2, 2016
  4. Organic Chemistry


    posted on March 25, 2016
  5. Chemistry

    q = 3.4 x 334 J/g

    posted on February 25, 2016
  6. Chemistry - Urgent

    Determine the mass of 3.18 ×1023 atoms Cl.

    posted on November 16, 2015
  7. Chemistry

    so, I guess the question is "m of AgCl produced"???

    posted on October 10, 2015
  8. chemistry

    [base] > [acid] so your pH should be larger than pka. check DrBob's answer :)

    posted on October 10, 2015
  9. density of Magnesium!

    To find the volume of a HCP structure given the height and the lenght, you should use this formula: l^2*h*((3)^1/3)/2)

    posted on June 10, 2015
  10. chemistry

    10.4 grams

    posted on March 17, 2015
  11. Chemistry

    Where Co(NO3)_2 is the limiting reagent the mmoles of the precipitate will be related to the mmoles of Co(NO3)_2 originally present by the balanced stoich. and the filtrate will be colorless? And if Na_3PO_4 is the limiting reagent the filtrate will be

    posted on March 1, 2015
  12. Chemistry

    Procedure 0) The sodium phosphate, Na3PO4 solution has NPFA ratings of 1 (out of 4) for health, 0 for fire, and 0 for reactivity. Cobalt (II) nitrate has 2 for health, 0 fire, and 0 for reactivity. 1) Carefully label (1-­‐6) and weigh 6 small test

    posted on March 1, 2015
  13. chemistry


    posted on September 26, 2014
  14. science

    C6H12 = 6x12 + 6x1 = 78. The equation indicates that 2x78 = 156g benzene will produce 6542kJ. Using proportions you can then calculate that x/6542kJ = 8.1g / 156g x = 339.7kJ = 339700J. heat = mass x ΔT x 4.18J/g° ΔT = 339700J / (5691g x 4.18J/g°) =

    posted on November 17, 2013
  15. Chemistry

    What are answers of a) and b) ??

    posted on January 11, 2013
  16. Chemistry

    Image one (d) Image two (a) I hope this helps. :)

    posted on November 23, 2012
  17. Chemistry

    Btw, I did it the way you said and I still come up with the same conversion of 29.8 * (760/1)= 22648

    posted on October 25, 2012
  18. Chemistry

    Sorry, my post repeated by accident when i refresh my page

    posted on October 25, 2012
  19. chemistry

    I don't understand how you do (b), I got 173kJ for (a) and I understand Hess's law for (c), but (b) I really don't understand (b)

    posted on November 21, 2011
  20. organic chem

    cadaverine is AKA pentane-1,5-diamine

    posted on April 30, 2011