Chemistry

  1. Chemistry
    Calculate the relative mass of (ii) trixonitrate
  2. chemistry
    The radioactive decay of carbon-14 is first-order and the half-life is 5800 years. While a plant or animal is living, it has a constant proportion of carbon-14 (relative to carbon-12) in its composition. When the organism dies, the proportion of carbon-14 decreases as a result...
  3. Chemistry
    2NoBr>2NO+Br2 Kc=0.064 At equilibrium a 1.00L flask contains 0.030mole NOBr and 0.030mole of NO.How many moles of Br2 are present.
  4. Chemistry
    When K is measured for a reaction, the values obtained are 3.1 at 25°C and 7.42 at 35°C. Using the equation lnK=-(∆H°/R)(1/T)+(∆S°/R) (in the form y=mx+b) calculate ∆H° and ∆S° for the reaction PbCl2(s) --> Pb2+(aq) + Cl-(aq)
  5. Chemistry
    When K is measured for a reaction, the values obtained are 3.1 at 25°C and 7.42 at 35°C. Using the equation lnK=-(∆H°/R)(1/T)+(∆S°/R) (in the form y=mx+b) calculate ∆H° and ∆S° for the reaction PbCl2(s) --> Pb2+(aq) + Cl-(aq)
  6. Chemistry
    Only 0.0640 grams of PbF2 will dissolve in 100.0 mL of solution. From this data, calculate the Ksp by two methods.
  7. Chemistry
    Would your calculated Ksp value be greater, less, or the same, if the following occurred, please explain your reasoning. a. The CaSO4 was not saturated b. You accurately measured 20.00 mL instead of 25.00 mL using a pipet c. The CaSO4 solution contained 1.0 M NaCl (aq) d. When...
  8. Chemistry
    When K is measured for a reaction, the values obtained are 3.1 at 25°C and 7.42 at 35°C. Using the equation lnK=-(∆H°/R)(1/T)+(∆S°/R) (in the form y=mx+b) calculate ∆H° and ∆S° for the reaction PbCl2(s) --> Pb2+(aq) + Cl-(aq)
  9. Chemistry
    Some plants require acidic soils for healthy growth. Which of the following could be added to soil around such plants to increase the acidity of the soil? 1.iron(ii)sulphate 2. sodium sulphate 3.aluminum sulphate 4.iron(iii)sulphate 5.caesium sulphate. Write Chemical equations...
  10. Chemistry
    Calculate hydroxyl ion concentration, ph and the percent hydrolysis for 0.1M solution of sodium cyanide (hints know for cyanide ion is 2.5*10^-5).
  11. Chemistry
    Determine the vapour pressure lowering at 25 degree Celsius of 1.25molality sucrose solution assume the solution behaves ideally (sucrose is C12H22O11). The vapour pressure of pure water at 25 degrees Celsius is 23.8torr ( hint 50.0g of sucrose was used).
  12. Chemistry
    The density of a 15.00% by mass aqeous solution of acetic acid is 1.0181g/mL What(i)the molarity (ii)molality (iii) the mole fraction of each component?
  13. Chemistry
    What must be a concentration of benzoate ion in a 0.55M benzoic acid solution so that the ph is 5.00?
  14. Chemistry
    The osmotic pressure of solution containing 4 g of the solute per litre of the solution is 0.41 atm at 27. What is the molecular weight of the solute?
  15. Chemistry
    What will be the osmotic pressure of a solution containing 3.42 g sugar in one litre of solution at 27 [ Mol. Wt of sugar =342 ], R= 0.082 litre-atm/mol.deg].
  16. chemistry
    The volume of an aqueous solution of NaCl at 25oC is expressed as a function of the amount m in 1kg of solvent in the following form; V/cm3 = 1000.94 + 16.4 (m/mol) + 2.14 (m/mol)3/2 - 0.0027 (m/mol)5/2 Find the partial molar volume of NaCl and water in 1 mol kg-1 solution.
  17. Chemistry
    The solubility of lead (II) chloride in water is 4.50 g/L at 25 degrees C a. What is the molarity of Pb2+ in a saturated solution b. What is the molarity of Cl- in the solution in the previous problem c. What is the equilibrium constant for the reaction: PbCl2(s) --> Pb2+(...
  18. Chemistry
    The half – life for the disintegration of radium is 1590 years. Calculate the rate constant in seconds and also how many years will be taken for the disintegration of 80 percent of the material?
  19. chemistry
    A galvanic cell with e o cell = 0.30 v can be constructed using an iron electrode in a 1.0 m fe(no3)2 solution, and either a tin electrode in a 1.0 m sn(no3)2 solution, or a chromium electrode in a 1.0 m cr(no3)3 solution even though sn2+/sn and cr3+/cr have different ...
  20. Science- Chemistry
    The proteins in a mammalian cell account for 18% of its net weight. If the density of a typical mammalian cell is about 1.1 g/mL, and the volume of the cell is 4x10-9 mL, what is the concentration of protein in mg/mL?
  21. chemistry
    A chemist added 3.15 grams of HNO3 to a solution of the same acid with concentration of 9 mol/L. dilutes the resulting solution up to the 100ml volume. The resulting solution will have what concentration?
  22. chemistry
    1. How many kilograms are equal to 1500 centigrams? 2. Determine the number of liters in 6578 milliliters? 3. How many decimeters are equivalent to 0.45 kilometers?
  23. Chemistry
    State what happens on bubbling chlorine into a solution of iron (ii) chloride explain with equation
  24. chemistry
    You have a 250ppm solution of K with KCl, you want to prepare a 0.00100 mole of Cl, how many mililiter should be diluted to prepare 1 liter of solution
  25. Chemistry
    The pH of a solution prepared by mixing 55.0 mL of 0.183 M KOH and 10.0 mL of 0.145 M HC2H3O2 is ________. the answer is 13.122 however when i try to plug it into the Henderson Hasselbalch equation (pH= -log(1.8E-5)+log( 0.010065/0.00145) i am not getting 13.122 the limiting ...
  26. Chemistry
    Can you recommend an easily accessed site for chemistry topics for engineers. (Preferrably with topics of crystallization and inorganic chemistry)
  27. math, English, geography, chemistry, physics, economics, l
    the number 1 to 20 are written on pieces of paper and put in the box. if a piece of paper is picked at random, what is the probability of picking a paper with: an odd number, a prime number, a multiple of 3 and a square number
  28. math, English, geography, chemistry, physics, economics,
    the number 1 to 20 are written on pieces of paper and put in the box. if a piece of paper is picked at random, what is the probability of picking a paper with: an odd number, a prime number, a multiple of 3 and a square numbe
  29. Chemistry
    A solution contains 0.010 M BaCl2. Calculate the molarity of the ions in solution, the ionic strength of the solution, the activity coefficient of the barium ion and its activity. Repeat for the chloride ion. So I know the molarities for the ions in this compound ((Ba^2+) = 0....
  30. Chemistry
    What is the mass of glucose required to prepare 500ml of 1M solution
  31. General Chemistry
    Question: How do you calculate the molecular weight of something like: A_xB_yC where x=1, and y=0.5? Attempt to the soln: Let Molecular Weight be MW: Is it then: MW OF A_xB_yC [x=1, y=0.5] = (MW of A)x1 + (MW of B)x0.5 + (MW of C)? Am I doing this correctly?
  32. Chemistry
    Consider the titration of 10.00 mL of a 0.250 M aqueous solution of ethylenediamine (H2NCH2CH2NH2) with 0.250 M HCl(aq). pKb1 = 4.07 and pKb2 = 7.15. What is the pH of the solution after 7.50 mL of HCl are added?
  33. Chemistry
    Consider the titration of 10.00 mL of a 0.250 M aqueous solution of ethylenediamine (H2NCH2CH2NH2) with 0.250 M HCl(aq). pKb1 = 4.07 and pKb2 = 7.15. What is the pH of the ethylenediamine solution prior to the start of the titration?
  34. Chemistry
    A solution contains 0.010 M BaCl2. Calculate the molarity of the ions in solution, the ionic strength of the solution, the activity coefficient of the barium ion and its activity. Repeat for the chloride ion. Show all calculations please.
  35. Chemistry
    What volume of distilled water should be added to 400cm3 of 2.0mol/dm 3 H2SO4 to obtain 0.20mol/dm3 of solution
  36. chemistry
    If you have 500 ml of .15M Formic Acid, what is the pH of this solution? What is the pKa? How many grams of Sodium Formate would you have to add to raise the pH to 3.85? How many grams of HCl would you have to add to lower the new pH by .2 ?
  37. chemistry
    what is the mass of oxalic acid required to prepare 250cm3 of a 1.5M solution of the acid
  38. Chemistry
    Given that the K sp for CaF2 at 25°C is 3.9 × 10–11, will a precipitate form when 0.10 L of 2.3 × 10–4 M CaCl2 is added to 0.50 L of 5.0 × 10–3 M NaF? Assume volumes are additive. Please help me I have no clue where to start. Thanks!
  39. Chemistry
    A solution of the weak acid HA was titrated with 0.100 M NaOH. the pH measured when vb=ve was 4.62 mL was 4.62 mL. Calculate the Ka of weak acid. (vb= added base volume, ve= equivalence point reading)
  40. chemistry
    what mass of HCl is needed to decompose 50g of CaCO3
  41. Chemistry
    If 35.00 mL of 0.25 M NaOH(aq) is mixed w/ 20.00 mL of 0.400 M HClO4(aq), the result solution would be: So apparently the correct answer is BASIC, but I thought it would be neutral because the resulting solution would contain NaClO4 which has components of both a strong acid ...
  42. chemistry
    How many electrons contain the ion that has 13 protons 10 electrons and 15 neutrons?
  43. chemistry
    Calculate the volume of hydrogen gas from the C4H9O3N compound, under temperature or pressure conditions (STP).
  44. chemistry
    The mixture of 40 ml of water to 160 ml of solution with ph = 8, causes a change in the ph value. What is the value of the new PH. Use Log 2 = 0.3
  45. chemistry
    Indicate what type of compound (ionic or covalent) would be expected from the possible binary combinations of the following elements: O, F, Cs, CI, Na. Consider the elements ' negativity
  46. Chemistry
    What would the pH of the solution be if the salt NaHX is dissolved in water? What anion predominates at the first equivalence point of the titration of X^2- with H^+?
  47. Chemistry
    227 g of graphite and partial pressures of 2.00 bar CO2 and 125 bar CO are added to a sealed 1.00 L sealed container at 298 K. In which direction is the reaction spontaneous? Do I use deltaG= -RTInK equation to solve this question?
  48. Chemistry
    What is the reaction quotient (Q) of: C(graphite)+ CO2(g) = 2 CO (g)
  49. Chemistry
    What is the energy change per mole of lauric acid (C12H24O2) burned?
  50. Chemistry
    Acetic anhydride, C4H6O3, has a normal boiling point of 139.8 C (ie, at 1.013 bar) and a standard enthalpy of vaporization of 51. 9 KJ mol^-1. What is the vapour pressure of acetic anhydride at room temperature (298 K) in units of bar? Can someone help me solve this question, ...
  51. Chemistry
    How much heat is required to convert 9.00 g of water at 100°C into steam at 100°C, if ∆Hvap for water = 40.7 kJ/mol?
  52. chemistry
    explain why pure dry benzoic acid do not affect litmus paper
  53. chemistry
    What volume of 0.1M Of sulphuric acid is needed to neutralize 100cm³ of a solution of sodium carbonate of mass concentration 20gram over dm³
  54. chemistry
    what volume(in cm3) of lead (density=11.3 g/cm3 ) has the same mass as 100 cm2 of red wood (density = 0.38 g/cm3)?
  55. Chemistry
    How many moles of mercury will be produced by electrolysis 1 m hg (no3)^2 solution with a current of 2A for 3 hours. Hg (no3)^2=200.6
  56. Chemistry
    What is the pH of a 50.0 mL solution containing 1.53 g of sodium sulfate. This is a diprotic base.
  57. Chemistry
    a) If 2.40 g NaHCO3 is added to 150 mL of 0.200 M HCl, calculate the molarity of H+ after the reaction above goes to completion. b) What volume, in mL, of 0.900 M KOH would be required to neautralize the remaining HCl in the problem above?
  58. Chemistry
    When one half teaspoon of baking soda is dissolved in your stomach, what volume of carbon dioxide gas would be produced at body temperature and 1.00 atm. pressure? On the average, one half teaspoon of baking soda contains 2.40 g of sodium bicarbonate. Assume the net ionic ...
  59. Chemistry
    Determine the equilibrium constant for a 0.10M phenol (HC6H5O) solution that has a pH of 5.43 at 25 degrees C. What is the degree of ionization of this weak acid? Why is the pH value important for this problem?
  60. chemistry
    There are 3.01X1023 atoms of gold, 1 mole of platinum, 3.01 moles of silver. Which one contains more atoms
  61. chemistry
    What is the %v/v concentration of a solution made by adding 25 ml of acetone to 75 ml of water?
  62. chemistry
    A 75.0g sample of liquid contains 17.5% by mass of H3PO4 (molar mass = 98.0g/mol). If 215.0mL of Ba(OH)2 is needed to completely neutralize the acid, determine the concentration of the Ba(OH)2 solution used
  63. Chemistry
    What is the E standard of the cell and delta G at 25centigrade when n=2 and K=75
  64. Chemistry
    What is the complete redox reaction of KMnO4 against (NH4)2Fe(SO4)2
  65. Chemistry
    If 0.314g sample of a solid monoprotic acid were dissolved in water and titrated to an end point that required 44.2 mL of 0.115M NaOH, what is the molecular mass of the unknown acid?
  66. Chemistry
    How many Ml of 0.200 M NaOH are needed to neutralize 15.00 mL of the 0.100 M hypothetical acid H2A?
  67. Chemistry
    The molecular weight of an unknown gas is found by measuring the time required for a known volume of the gas to effuse through a small hole, under constant pressure. The apparatus is calibrated by measuring the time needed for the same volume of O2 (Molecular weight =32g/mol) ...
  68. Chemistry
    × a 25cm³ aliquot of ammonium iron(ii) tetraoxomanganate(vii) containing 32.9g of its salt in 250cm³ solution, needed 25cm³ of potassium tetraoxomanganate(vii) solution for a colour change to occur. what is the concentration of the potassium tetraoxomanganate(vii) solution...
  69. Chemistry
    Molecular mass of Mg(no3)2.6h2o
  70. chemistry
    × a 25cm³ aliquot of ammonium iron(ii) tetraoxomanganate(vii) containing 32.9g of its salt in 250cm³ solution, needed 25cm³ of potassium tetraoxomanganate(vii) solution for a colour change to occur. what is the concentration of the potassium tetraoxomanganate(vii) solution...
  71. Chemistry 11
    What is the total ionic equation and net ionic equation of ammonium sulphide solution added to gold nitrate solution?
  72. Chemistry 11
    What volume of 2.33 M of sodium hydroxide solution is needed to fully neutralize 1000.0 cm3 of 17.6 M hydrobromic acid?
  73. Chemistry 11
    What is the concentration of the solution formed when zinc metal is reacted with 950.0 cm3 of 1.25 M hydrochloric acid? What is the volume of hydrogen gas (at stp) that is evolved in the same reaction?
  74. chemistry
    consider the balanced chemical equation 2H2O2 ---> 2H2) + )O2 A) given 20.0 g of H2O2 how many grams of water will be produced? B) how many grams of H2O2 will you need to get 20.0 g of water ? C) how many grams of H2O2 will you need to get 20.0 g of O2 D) for your answer in...
  75. chemistry
    sodium metal reacts with hydrogen gas to yield solid sodium hydride ( NaH ). A reaction mixture contains 10.00 g sodium metal and 0.235 g of hydrogen gas. write a balanced chemical equation for this reaction? what is your limiting reactant? what is your theoretical yield (in ...
  76. Chemistry
    If the solubility of Ag2CO3 is 1.3x10^-4 mol/L, what is its Ksp? (the answer is said to be 8.8x10^-12) Ag2CO3(s) -----> 2 Ag+ (ag) + CO3 2- Ksp= [Ag+]^2 [CO3^2-] = [1.3x10^-4]^2[1.3x10^-4] =2.197x10^-12 thats what I did, but I found that if you first multiplying the 1.3x10...
  77. Chemistry II: equilibrium and thermodynamics
    Ca(OH)2 dissolves exothermically in water and the molar solubility of Ca(OH)2 decreases as the temperature increases. What are the signs of delta H and delta S for dissolving Ca(OH)2?
  78. chemistry
    What volume of 0.307 m naoh must be added to 200.0ml of 0.425m acetic acid (ka = 1.75 x 10-5 ) to produce a buffer of ph = 4.250?
  79. Chemistry
    20 cm3 of 1 M H2SO4 is mixed with 20 cm3 of 1 M NaOH. The resulting solution is? A. acidic with a molarity of 0.50 M H2SO4 B. acidic with a molarity of 0.25 H2SO4 C. neutral D. alkaline with a molarity of 0.25 M NaOH E. alkaline with a molarity of 0.50 M NaOH
  80. chemistry
    30cm³ of 0.1 M AI(NO3)3 solution is reacted with100cm³ of 0.15M of NaOH solution. Which is in excess and by how much? A. NaOH solution, by 70cm³ B. NaOH solution, by 60cm³ C. NaOH solution by 40cm³ D. AI (NO3)3, solution by 20cm³ E. AI (NO3)3 solution, by 10cm³
  81. Chemistry
    Hess'slaw can be applied to calculate the reaction is?
  82. chemistry
    In the chlorine titration of a solution prepared by the dissolution of 0.2110 g of commercial hypochlorite was spent 19.50 ML of sodium thiosulphate solution 0.1002 mol/L. Calculate the percentage of chlorine (35.45 g/mol) in this sample
  83. chemistry
    what is kind of reaction is 2C(s)+mno2(s)Mn(s)+2co(g)
  84. Chemistry
    An antacid tablet contains the weak base Mg(OH)2. After crushing the tablet and adding 20.00 mL of 1.00 M HCl(aq) to it, the remaining acid is titrated to the end point with 29.50 mL of 0.495 M NaOH. How many milligrams of Mg(OH)2 were present in the tablet?
  85. Chemistry
    CH4 diffuses twice as fast as Y.Molecular weight of Y is : a. 16 b. 32 c. 48 d. 64
  86. Chemistry
    Is this EXTENSIVE OR INTENSIVE? 1. number of calories in 10 grams of sugar. 2. Percentage of alcohol in a beer. 3. Electrical resistance of 1km length of 22 gauge copper wire 4. Electrical resistance of 22 gauge copper wire.
  87. Chemistry
    Iron is extracted from the mineral magnetite, Fe3O4: Fe3O4 (s) + 2 C (s)  3 Fe (s) + 2 CO2 (s) A 35.0 g sample of magnetite is reacted with 4.0 g of carbon, and 15.0 g of iron is produced. Determine the percentage yield of this reaction. (6)
  88. Chemistry
    What is the concentration of an unknown sulfuric acid solution if 0.2M Sodium hydroxide is titration to neutralize the acid? The initial volume of the Sodium hydroxide is .50ml and the final volume is 30.75 ml. There is 35mL of acid.
  89. Chemistry
    What is the concentration of a solution of sodium hydroxide if I mix 15.0g of sodium hydroxide with enough water to make 500.0ml of solution?
  90. Chemistry
    Can you show me how to calculate this equation? What is the concentration of phosphoric acid solution of 30.0ml of a 0.2M of Potassium hydroxide is used to neutralize. The volume of acid is 20.0ml.
  91. chemistry
    A silver wire is immersed in a solution containing ions of CU2 + what is expected in this situation? A) no reaction occurs. b) The silver wire is oxidized. c) Copper is deposited on the silver wire. D) The ions Cu2 + are reduced.
  92. Bio and organic chemistry
    How do I prepare 250ml of 0.5M acetic acid by dilution of 3M CH3COOH?
  93. chemistry
    The melting temperatures of the two isomers of molecular formula C2H6O are-139 °c and-115 °c. Knowing that one of the isomers is an alcohol and the other a ether, indicate the melting temperature corresponding to each of them
  94. Chemistry
    Hydrogen iodide decomposes according to the following equation: H2(g) + I2(g) ⇌ 2HI(g) A 2.50 L equilibrium mixture contains 0.0875 mol H2, 0.020 mol I2, and 3.72 mol HI. Determine the new equilibrium concentrations after 1.25 mol HI are added to the system. This is what I'...
  95. chemistry
    A sulphuric acid density solution of 1.38 g/ml has a concentration of 56% w/w. Calculate the amount of moles of the existing acid in 1 litre of this solution.
  96. chemistry
    What is the g/L concentration of a solution terminating 10g of NaCI with 95% purity in 250 ml of water?
  97. CHEMISTRY
    A is a solution of trioxonitate acid of an unknown concentration, B is a standard solution of sodium hydroxide containing 4.00g per dm3 of solution 25cm3 portion of solution B require an average of 24cm3 of solution A for complete neutralization. Write a balance equation for ...
  98. CHEMISTRY
    A is a solution of trioxonitate acid of an unknown concentration, B is a standard solution of sodium hydroxide containing 4.00g per dm3 of solution 25cm3 portion of solution B require an average of 24cm3 of solution A for complete neutralization. Write a balance equation for ...
  99. Chemistry
    A 1.00 L flask is filled with 1.05 g of argon at 25 ∘C. A sample of ethane vapor is added to the same flask until the total pressure is 1.150 atm . a.)What is the partial pressure of argon, PAr, in the flask? b.)What is the partial pressure of ethane, Pethane, in the flask?
  100. Chemistry
    A gaseous mixture of O2 and N2 contains 37.8 % nitrogen by mass. What is the partial pressure of oxygen in the mixture if the total pressure is 485 mmHg ?
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