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Most popular questions and responses by eng
  1. chemistry

    1)The reaction of methane and oxygen yields carbon dioxide gas and water. The unbalanced reaction is as follows: CH4(g) + O2(g)CO2(g) + H2O(g) A. If 0.718 grams of methane are reacted, how many grams of water vapor are produced? B. If 1.621 grams CO2 are

    asked on January 7, 2010
  2. chemistry

    Based on the balanced equation 2Al + 6HCl → 2AlCl3 + 3H2 calculate the number of excess reagent units remaining when 140 Al atoms and 402 HCl molecules react?

    asked on February 12, 2010
  3. Physics

    A potential energy function for a two-dimensional force is of the form U = 3 x^(4)y - 8 x. Find the force that acts at the point (x, y). (Use x and y as appropriate.) I know its something about partial derivatives but I'm not sure how to go about it. And

    asked on February 7, 2010
  4. chemistry

    Gaseous carbon monoxide reacts according to the balanced equation. If a total of 1040 kJ of heat is generated in the reaction as written, how many grams of CO2 are produced? enthalpy=-566kJ 2 CO(g) + O2(g) → 2 CO2(g)

    asked on February 25, 2010
  5. chemistry(check my answer)

    Which equation describes the relationship between the rates at which Cl2 and F2 are consumed in the following reaction? Cl2(g) + 3F2(g) yield 2ClF3(g) a)-d(Cl2)/dt = -d(F2)/dt b)-d(Cl2)/dt = 2[-d(F2)/dt] c)3[-d(Cl2)/dt] = -d(F2)/dt d)2[-d(Cl2)/dt] =

    asked on May 14, 2010
  6. chemistry

    CoSO4 + KI + KIO3 + H2O  Co(OH)2 + K2SO4 + I2 2KI yield I2 + 2e 2KIO2 10e yield I2 are there 10 electrons being transferred or just 5 only

    asked on June 6, 2010
  7. chemistry

    Based on the balanced equation 2Ba + O2 → 2BaO calculate the number of BaO formula units formed when 142 Ba atoms and 73 O2 molecules react?

    asked on February 12, 2010
  8. math

    for this infinite series (-1)^n/n^2 if i use alternating series test to show that sequence does of a^n does not go to 0, then does this mean that this series is diverging

    asked on July 27, 2010
  9. chemistry(check my work)

    If 6.01 g of K2SO3 dissolved in 930 mL of water reacts stoichiometrically according to the balanced equation in a reaction solution with a total volume of 990 mL, what is the molarity (M) of KCl produced? K2SO3(aq) + 2 HCl(aq) → SO2(g) + 2KCl(aq) +

    asked on April 3, 2010
  10. chemistry

    Which equation describes the relationship between the rates at which Cl2 and F2 are consumed in the following reaction? Cl2(g) + 3F2(g) yield 2ClF3(g) a)-d(Cl2)/dt = -d(F2)/dt b)-d(Cl2)/dt = 2[-d(F2)/dt] c)3[-d(Cl2)/dt] = -d(F2)/dt d)2[-d(Cl2)/dt] =

    asked on May 14, 2010
  11. chemistry

    Pt(s) | Mn2+(aq), MnO4-(aq), H+(aq) || H+(aq), IO3-(aq) | I2(s) | Pt(s) Pt(s) | Mn2+(aq) | MnO2(s) | H+(aq) || H+(aq) || PbO2(s) | Pb2+(aq) | Pt(s) how come the first one has comas within cell notation but not the second one,

    asked on June 3, 2010
  12. chemistry

    A balanced equation that represents an overall cell reaction is shown. Choose the cell notation which corresponds to the electrochemical cell that is described by this equation. 2H2O(l) → 2H2(g) + O2(g) i don't get why the answer is this. How can OH-

    asked on June 3, 2010
  13. chemistry

    1)RuO2 is molecular, but why is it insulator even though Ru is metal? 2)Why is TiO ionic? I thought only group 1 and 2 would make ionic compound 3)If the the compound has metal and metalloid like GaAs, is it always semiconductor

    asked on February 21, 2010
  14. chemistry

    for the reaction, determine the number of transferring electrons so then i can pug into G=-nFE I'm assigning charges to each of the elements H2O2(aq) + 2ClO2(g) → O2(g) + 2HClO2(aq) (+1,-1) + (+4,-2) (0) (+1,+1,-2) since O changes from -1 to 0, so it

    asked on June 3, 2010
  15. chemistry

    Does the basicity decreases as going down the column and right across the periodic table? How does the size of an element or electronegativity apply to strength of basicity and acidicity?

    asked on March 23, 2010
  16. chemistry(check my steps)

    The electrochemical cell described by the cell notation has a standard cell potential of -0.35 V. Calculate the Wmax (kJ) the cell has done if 1893.5 g of MnO42-(aq) (Molar Mass - 118.94 g/mol) forms. Round your answer to 3 significant figures. Pt(s) |

    asked on June 3, 2010
  17. chemistry

    how do i write this reaction in cell notation I2(s) + 2MnO4-(aq) + 4H+(aq) → 2IO3-(aq) + 2Mn2+(aq) + 2H2O(l)

    asked on June 1, 2010
  18. physics

    An auditorium measures 35.0 m multiplied by 15.0 m multiplied by 5.0 m. The density of air is 1.20 kg/m3. What is the weight of air in the room in pounds? i got 4.25 x 10^5 and the page says that "Your response differs from the correct answer by orders of

    asked on January 8, 2010
  19. chemistry

    The electrochemical cell described by the cell notation has a standard cell potential of -0.35 V. Calculate the Wmax (kJ) the cell has done if 1893.5 g of MnO42-(aq) (Molar Mass - 118.94 g/mol) forms. Round your answer to 3 significant figures. Pt(s) |

    asked on June 4, 2010
  20. chemistry(check my work on anothe rproblem)

    When a reaction mixture with a total volume of 1390 mL that is 0.00791 M aqueous Ba2+ was stoichiometrically produced as per the balanced equation, what mass (g) of Ba2+ was required? Ba(OH)2(aq) + 2 HClO4(aq) → Ba(ClO4)2(aq) + 2 H2O(l) .00791x1.39=mole

    asked on April 3, 2010
  21. chemistry(please check my work)

    If 0.836 g of solid Al reacts stoichiometrically according to the balanced equation in a reaction solution with a total volume of 1160 mL, what mass (g) of gaseous H2 is produced? 6 HClO4(aq) + 2 Al(s) → 3 H2(g) + 2 Al(ClO4)3(aq) 0.836g/molecular weight

    asked on April 3, 2010
  22. chemistry

    1)gaseous sulfur trioxide and gaseous nitrogen monoxide form when gaseous sulfur dioxide and gaseous nitrogen dioxide react. 2)Enter the formula of the missing substance ( Y ) in the balanced equation below. Do not give the coefficient. C2H4 + 3Y → 2CO2

    asked on February 6, 2010
  23. physics

    An automobile tire is rated to last for 60,000 miles. To an order of magnitude, through how many revolutions will it turn? i put 10E7 but i got it wrong since i used 1rev/8ft

    asked on January 8, 2010
  24. chemistry

    Based on the balanced equation 2I2O5 + 10NO → 5N2O4 + 2I2 calculate the number of excess reagent units remaining when 188 I2O5 molecules and 850 NO molecules react? do i start with a new balance equation in order to solve it

    asked on February 10, 2010
  25. chemistry

    Which of the following rate laws suggests that the reaction probably occurs in a single step? why is this problem cant be answer a since it has order of 1 a)(CH3)3CBr + OH- →(CH3)3COH + Br- rate = k[(CH3)3CBr] b)NO(g) + O2(g) → NO2(g) + O(g) rate =

    asked on May 18, 2010
  26. chemistry(check my work)

    When a reaction mixture with a total volume of 1720 mL that contains 0.605 L of gaseous CO2 measured at STP dissolved in 940 mL of water was stoichiometrically produced as per the balanced equation, how many mol of solid CaCO3 were required? H2SO4(aq) +

    asked on April 2, 2010
  27. chemistry

    Liquid quinoline reacts according to the balanced equation. When 1200 g of C9H7N is reacted, calculate the sign and magnitude (kJ) of the heat produced. 4 C9H7N(l) + 43 O2(g) → 2 N2(g) + 36 CO2(g) + 14 H2O(l) .

    asked on February 23, 2010
  28. chemistry

    Using the balanced equation, determine the number of NaNO3 units in the visualization in the reaction. 3Ca(NO3)2(aq) + 2Na3PO4(aq) → 6NaNO3(aq) + Ca3(PO4)2(s)

    asked on January 20, 2010
  29. chemistry

    Wich of the following is NOT true about the blank for the experiment, 'Analysis of a Complex Iron Salt'? A. A blank is titrated to correct for any reactive impurities in the solvent. For this experiment, the impurities would be reducing agents that would

    asked on April 17, 2010
  30. chemistry

    If 0.755 g of Al3+ dissolved in 960 mL of water reacts stoichiometrically according to the balanced equation, what volume (mL) of 0.0875 M aqueous Cl- is required? Al2(SO4)3(aq) + 3 BaCl2(aq) → 2 AlCl3(aq) + 3 BaSO4(s)

    asked on April 3, 2010
  31. math

    for a strict triangular form, does it has to be in I matrice or just the main diagonal entries are all 1]\

    asked on July 1, 2010
  32. chemistry

    HCl (aq) + Cu (s) + HNO3 (aq) yield CuCl2 (aq) + NO (g) + H2O (l) do i say that HNO3 is oxidizing agent or just N+5 is the oxidizing agent

    asked on June 6, 2010
  33. physics

    if the system is a basket, the basket is tied to a rope and it is stopped by a fixed clamp when it is falling down, I know there is initial KE but how come initial work is negative. Isnt force and displacement are in the same direction, so work should be

    asked on May 25, 2010
  34. chemistry

    Which of the following rate laws suggests that the reaction probably occurs in a single step? why is this problem cant be answer a since it has order of 1 a)(CH3)3CBr + OH- →(CH3)3COH + Br- rate = k[(CH3)3CBr] b)NO(g) + O2(g) → NO2(g) + O(g) rate =

    asked on May 17, 2010
  35. chemistry(check my answer)

    Which of the following will be affected by the addition of a catalyst to a chemical reaction? a)the value of the reverse rate constant, kr b)the magnitude of the equilibrium constant c)the value of the forward rate d)ΔHo e)the value of the forward rate

    asked on May 14, 2010
  36. chemistry(check my answer)

    Which equation describes the relationship between the rates at which Cl2 and F2 are consumed in the following reaction? a)-d(Cl2)/dt = -d(F2)/dt b)-d(Cl2)/dt = 2[-d(F2)/dt] c)3[-d(Cl2)/dt] = -d(F2)/dt d)2[-d(Cl2)/dt] = -d(F2)/dt e)-d(Cl2)/dt = 3[-d(F2)/dt]

    asked on May 13, 2010
  37. chemistry(check my work)

    Which of the following is NOT true of colligative properties? Colligative properties are... A. dependent on the mass of solute present. B. independent of the chemical identity of the solute. C. dependent on the molar mass of the solute. D. responsible for

    asked on April 6, 2010
  38. calculus

    why is lim of tanx as x approaches to (pie/2)+ is negative infinity. Shouldnt it be positive infinity since pie/2 is approaching on the right

    asked on February 28, 2010
  39. chemistry

    is CaO soluble

    asked on February 22, 2010
  40. chemistry

    1) Calculate the specific heat capacity (J/g oC) of iron, if a 803 g sample lost 937.4 J of heat energy in going from an initial temperature of 5.50 oC to a final temperature of 2.90 oC. 2)Calculate the final temperature (oC) of a 243 g sample of water

    asked on February 17, 2010
  41. chemistry

    If 600 mL of 1.05 M aqueous CaCl2 and 720 mL of 0.792 M aqueous Na3PO4 are reacted stoichiometrically according to the balanced equation, how many milliliters of 0.792 M aqueous Na3PO4 remain? Round your answer to 3 significant figures.

    asked on February 13, 2010
  42. chemistry

    Based on the balanced equation, 10Li + N2F4 → 4LiF + 2Li3N calculate the formula units of LiF formed when 54 molecules of N2F4 are reacted. since one mole of N2F4 yields 4LiF, then 54N2F4 yields 216LiF, am i correct

    asked on February 10, 2010
  43. chemistry

    Transfer the tablet to a clean 125-mL Erlenmeyer flask. Add 10-mL of 1M NaOH and heat the mixture to a gentle boil. Once the solution has cooled to room temperature, transfer it to a 100-mL vol. flask. Using the diluted solution from the 100-mL volumetric

    asked on January 31, 2010
  44. chemistry

    1) 14 moles of Ar 12 moles of N2 2 moles of BF3 If the total number of mol present in the mixture visualized is 1.43, calculate the number of mol of N2. 2) 11 moles of N2 4 moles of CSH4 If the total number of mol present in the mixture visualized is 1.68,

    asked on January 15, 2010
  45. chemistry

    Infrared, ultraviolet, and visible radiation are all part of the electromagnetic spectrum. Arrange the three types of radiation in order of increasing energy? i put visible

    asked on January 11, 2010
  46. chemistry

    A. What is the mass of Solution 3? in g B. What is the density of Solution 2? g/ml solution 1: Mass Empty Flask (g):42.252 Mass NaCl (g):0.911 Volume Water (mL):100 Mass of Flask + Solution (g):43.107 solution 2: MEF: 45.778 mass nacl:0.897 volume water:

    asked on January 8, 2010
  47. chemistry

    do we have buffering region and ph=pka in any of these conditions: strong base vs strong acid strong base vs weak acid weak base vs strong acid weak base vs weak acid

    asked on May 23, 2010
  48. chemistry(check my asnwer)

    Why doesn't potassium ion K+ from KMnO4 appear in the following two unbalanced equations: MnO4– + C2O42– Mn2+ + CO2 MnO4– + Fe2+ Mn2+ + Fe3+ ? A. KMnO4 is not added to either reaction. B. The presence of K+ would result in a net positive charge in

    asked on April 17, 2010
  49. chemistry(check my explanation)

    sorry to repost this question but i'm confused on this part The solubility of borax is directly proportional to temperature. Therefore, the sign of H is A. negative B. positive C. unknown with the given information like you said earlier, borax dissolves

    asked on April 5, 2010
  50. chemistry

    When a reaction mixture with a total volume of 1750 mL that is 0.0263 M aqueous K+ was stoichiometrically produced as per the balanced equation, what volume (mL) of 0.0326 M aqueous K3PO4 was required? 3 BaBr2(aq) + 2 K3PO4(aq) → Ba3(PO4)2(s) + 6 KBr(aq)

    asked on April 2, 2010
  51. chemistry

    A 1.00 L volume of 0.609 M HNO3 is condensed to a volume of 0.750 L, calculate the molarity (M) of H+ in the new solution

    asked on March 28, 2010
  52. chemistry

    Calculate the molality (m) of CH2Cl2 in a solution generated by combining 846 g of the solute CH2Cl2 with 11.2 L of the solvent ethanol.

    asked on January 20, 2010
  53. science

    if i use 30 ul from a total volume of 600ul to get 40ug/ml. So to get the total ug only, do i take 40ug/ml*.030ml*(600ul/30ul)=total ug

    asked on May 12, 2012
  54. electrical engineering

    Input range: -100mV to +60mV Voltage supplies to the op-amp= ±15V how do we find the input offset voltage?

    asked on February 3, 2012
  55. physics

    how do i calculate the pressure of a pipe with same area and constant velocity. I tried to use bernoulli's equation but it only applies if the area of the opening and end are not the same

    asked on October 7, 2011
  56. math

    how is this series 3+ 9/4 +27/16 +81/64... is converge to 12? i represent the series as 3^(n+1)/4^n n starts from 0 to infinity, is this correct formula

    asked on July 16, 2010
  57. physics

    for both of these object system1: earth and ball if a ball is falling down, is the work done on it positive since force and displacement are in the same direction. system 2: earth and basket a basket is tied to a rope and is dropped then come to a full

    asked on May 25, 2010
  58. chemistry

    A 50-mL Mohr buret is connected to a 1-ft length of capillary tubing. The buret is then filled with water and the volume of water versus time is monitored as the water gradually flows through the capillary tubing. This process is found to be first-order

    asked on May 16, 2010
  59. chemistry

    what does it mean by in phase and out of phase for orbitals. Is in phase means that it's bonding and out of phase is antibonding?

    asked on May 12, 2010
  60. chemistry(check my answer)

    From the Standard Potential Table in your general chemistry textbook: Which reaction has been chosen as the 'standard' against which every other reaction is measured? A. 2H+ + 2e–H2 B. Li+ + e–Li C. O2 + 4H+ + 4e–2H2O D. F2 + 2e–2F– E. H2 +

    asked on April 29, 2010
  61. chemistry

    Why is HF has lower boiling point than CsI, even though HF has hydrogen bond. Does HF have higher boiling point than O2

    asked on March 13, 2010
  62. chemistry

    by the way, how can you tell if work is 0 for 2 mol of solid iron (C = 25:1 J/(molK)) is heated from 20C to 200C. How much does its internal energy change?

    asked on March 11, 2010
  63. chemistry

    2 mol of solid iron (C = 25.1 J/(mol K)) is heated from 20C to 200C. How much does its internal energy change? U = q +W but no matter exchange so work is 0. then U=q=9036J But why is q not negative since isnt the system loses its heat to the surrounding

    asked on March 9, 2010
  64. chemistry

    what if compound has those metalloids(metal near stair case) with gas element, is it going to be semiconductor. Can you think of any other compound with metalloid and gas elements beside SiO2 that is insulator

    asked on February 21, 2010
  65. chemistry

    for NaTl, is the unit cell of it based on the repetition of body centered cubic and the holes in this unit cell are octahedral? how many of each of the 2 cubes drawn for NaTl are required its unit cell? is it 8?

    asked on February 15, 2010
  66. chemistry

    A 4.14 m solution of the solute methylene chloride dissolved in the solvent ethanol is available. Calculate the mass ( kg ) of the solution that must be taken to obtain 1487 g of methylene chloride. CH2Cl2-1327 (kg/m^3) C2H5OH-789.3 (kg/m^3)

    asked on January 28, 2010
  67. chemistry

    You have 2.0 g of solid A, 100.00 mL of water (100.0 g of water), and the total mass of solid A combined with 100.00 mL of water is found to be 102.0 g. The mass percent of A in this solution is

    asked on January 7, 2010
  68. 12th grade

    Does knowledge acquired in highschool liberate or hinder students? Please help explain the question and your opinion.

    asked on September 26, 2009
  69. science

    if i use 30 ul from a total volume of 600ul to get 40ug/ml. So to get the total ug only, do i take 40ug/ml*.030ml*(600ul/30ul)=total ug

    asked on May 12, 2012
  70. math

    how do i represent 1/(1+x^4) in general taylor polynomial. I know the pattern is 1-x^4+x^8-x^16..... I don't know how to represent this pattern in variables equation form. What i mean by general taylor polynomail is for example 1/(1-x)=1+x+x^2+x^3...+x^n.

    asked on July 20, 2010
  71. math

    how do i represent 1/(1+x^4) in general taylor polynomial. I know the pattern is 1-x^4+x^8-x^16..... I don't know how to represent this pattern in variables equation form

    asked on July 19, 2010
  72. chemistry

    If 0.0490 mol of solid Al reacts stoichiometrically according to the balanced equation with 990 mL of aqueous Cl-, what molarity (M) of Cl- is required? 3 CuCl2(aq) + 2 Al(s) → 3 Cu + 2AlCl3(aq)

    asked on April 2, 2010
  73. chemistry

    please check my answer(one with star). The solubility of borax is directly proportional to temperature. Therefore, the sign of H is A. negative* B. positive C. unknown with the given information since solubility shifts the reaction to the right, therefore

    asked on March 29, 2010
  74. chemistry

    is Li3As a semiconductor

    asked on March 14, 2010
  75. chemistry

    did i order the intermolecular forces correctly ion-ion > ion-dipole force > dipole-dipole >ion-induced dipole> dipole-induced dipole> hydrogen bond>dispersion bond

    asked on March 14, 2010
  76. chemistry

    lets just say that 5g of solid benzoic acid burns under gaseous oxygen atmoshphere. Temperature increases from 20c to 50c. So is this exothermic so the sign is negative? how is it not the same as 2 mol of solid iron (C = 25.1 J/(mol K)) is heated from 20C

    asked on March 10, 2010
  77. physics

    if velocity vector is changing but speed is constant, can there still be work

    asked on March 5, 2010
  78. physics

    if a particle has work of 8J and doubles its speed. how much work it has done? Can we still determine work in this problem without mass

    asked on March 4, 2010
  79. chemistry

    for NaTl, is the unit cell of it based on the repetition of body centered cubic and the holes in this unit cell are octahedral?

    asked on February 16, 2010
  80. chemistry

    If 6.38 g of a polyethylene glycol is dissolved in 7550 ml of water at 300 oK, the solution has an osmotic pressure of 0.171 torr. Calculate the molar mass (g/mol) of the polyethylene glycol.

    asked on January 28, 2010
  81. chemistry(check my answers please)

    1)An increase in temperature ____________ the kinetic energy and average speed of the gas particles. A. decreases B. increases 2)As a result, the pressure on the walls of the container __________. A. decreases B. increases C. is not affected 1) i think its

    asked on January 23, 2010
  82. chemistry

    Why isn’t the six atom ring created when ASA binds to Fe3+ flat like the benzene ring? is it because that Fe3+ distorted the angles tats why it is not flat

    asked on January 21, 2010
  83. chemistry

    How do the bond angles in the six atom ring (created when ASA binds to Fe3+) differ from the bond angles of the six atom benzene ring? are there even any tetrahedral angles in here because the angles i found are 123.66,124.12,119.15,114.71,89.86. Some are

    asked on January 21, 2010
  84. chemistry

    If the ratio of the rate of effusion of an unknown gas to that of CO under the same conditions is 0.7978, calculate the molar mass (g/mol) of the gas

    asked on January 15, 2010
  85. ENGLISH higschool

    Does knowledge acquired in highschool liberate or hinder studnets?

    asked on September 26, 2009
  86. english

    What is the difference between poems and poetry?

    asked on May 28, 2008
  87. biology

    are both ER and secretory vesicles have double bilayer membrane

    asked on January 5, 2011
  88. math

    how do i represent 1/(1+x^4) in general taylor polynomial. I know the pattern is 1-x^4+x^8-x^16..... I don't know how to represent this pattern in variables equation form

    asked on July 19, 2010
  89. math

    in a skew symmetric, how do we explain that its diagonal entries has to be all 0 without giving examples to support it

    asked on June 30, 2010
  90. engineering

    what is the device used called for eye laser surgery and do you know which company use it

    asked on June 23, 2010
  91. engineering

    what is the device called for eye laser surgery and do you know which company use it

    asked on June 23, 2010
  92. chemistry

    can you what is G and G knot in terms of spontaneity and chemical equilibrium. I know that G is spontaneous when is negative but what does G knot tell you

    asked on June 4, 2010
  93. chemistry

    when do we have pka=ph

    asked on May 23, 2010
  94. physics

    in an adiabatic process from A to B, do A and B have same temperature?

    asked on May 3, 2010
  95. chemistry(check my answer)

    For the cell: C(s) C+(aq) B+(aq) B(s). Metal ______ is the "negative" electrode. is it C(s)

    asked on April 30, 2010
  96. math

    how do you take log(-63)

    asked on April 28, 2010
  97. calculus

    when finding area, what does it mean when it says that the function is below by the x-axis, can you give me example of this

    asked on April 27, 2010
  98. chemistry(check my work)

    The freezing point of a solution is A. lower than the freezing point of the solvent alone because higher temperature is required to accelerate solvent molecular motion enough to overcome obstructon by solute particles.. B. higher than the freezing point of

    asked on April 6, 2010
  99. chemistry

    If 1373 g of a substance is dissolved in 2315 g of cyclohexane solvent, the boiling point of the solution is 87.69 oC. Calculate the apparent molar mass (g/mol) of substance.

    asked on January 31, 2010
  100. chemistry

    If 1373 g of a substance is dissolved in 2315 g of cyclohexane solvent, the boiling point of the solution is 87.69 oC. Calculate the apparent molar mass (g/mol) of substance.

    asked on January 31, 2010