1. math

    calculate the resistances of (a) 100-watt 120-volt incandescent lamp, (b) a 750-watt 115-volt toaster, (c) a 1300 watt 110-volt portable iron.

    asked by lee on August 24, 2014
  2. physics

    a hose pipe ejects water at a speed of 0.3m/s through a hole of area 50 cm*m.if the water strikes a wall normally, calculate the force on the wall , assuming the velocity of water normal to the wall is zero after striking?

    asked by mani on March 23, 2012
  3. Science

    The approximate concentration of hydrochloric acid in the stomach(stomach acid) is 0.17m.calculate the mass of the following to neutralise 50cm of stomach acid.a)bicarbonate of soda b)aluminium hydro xide

    asked by Rufinat on January 6, 2016
  4. science

    the potential difference between a cloud and the earth is 1000000000. in a lightning bolt 20c of charge pass from the cloud to the earth in a time of 0.004. calculate the current that flows from the cloud to the earth.

    asked by howard on August 13, 2018
  5. Algebra

    There are two solutions to | 16x - 5 | = 3. The greatest solution is ___. Since the expression, 16x - 5, can be either positive or negative, solve for both. 16x - 5 = 3 16x = 8 x = .5 -(16x - 5) = 3 -16x + 5 = 3 -16x = -2 x = 1/8 You can decide which is

    asked by Juri on July 23, 2007
  6. Biochemistry

    Complete hydrolysis of 25 mM ethyl acetate in an enzyme esterase catalyzed reaction is carried out in a 40 mM NaCl solution buffered by 0.2 M Tris-Cl, pH 9.1. What is the pH at the end of the reaction? (For Tris base, which is the abbreviation for Tris

    asked by Melissa on February 7, 2011
  7. Math, rational inequalities

    Please can someone help me solve this problem? 2/x + 6/x-1 less than or = -5 8/x -1 = -4x Divide both sides by 4 2 >= -x Multiply both sides by -1 -2

    asked by agirl on November 26, 2006
  8. chemistry

    The balanced equation is shown below. 2 HCl(aq) +CaCO3(s)=CaCl2(aq) +H2O(l) +CO2(g) 2.00 dm3 of a 3.00 M hydrochloric acid solution is added to the kettle (this is an excess). During the reaction 1.20 dm3 of CO2 is produced (assume 250C and 1 atmosphere)

    asked by Abaoaqu on October 27, 2014
  9. math

    Am i on the right track ? I have two percent problems. Please help. Deb's Bakery marks up a cake it makes for $10 by 55%. Round up to the nearest cent. * $10 x .55 = $5.50 * $10 + $5.50 = $15.50 * $15.51 The price of a loaf of bread went down to $0.45 from

    asked by Ryan on February 21, 2009
  10. Chemistry

    The two most common oxidation states are Cr(III) and Cr(VI). Balance the following oxidation-reduction equations that involve one of these oxidation states of chromium. Assume that the reactions occur in acidic solution. A. Cr(s) + O2 (g) + H^+ Cr^3+ B.

    asked by Anonymous on February 24, 2016
  11. math

    A school designer wants to create a whiteboard with the optimal dimensions to enhance learning. It is determined that if one side of the whiteboard is x + 5y inches, the other side should be x^2+3xy-4y^2 inches. Write an algebraic expression for the area

    asked by Mary Anna on July 17, 2011
  12. physics

    the small 2kg block A slides down the curve path and passes the lowest point B with a speed 4 m/s. If the radius of the curvature path at B is 1.5 m, determine the normal force N exerted on the block by path at this point. Is knowledge of the friction

    asked by samad on August 17, 2010
  13. chemistry

    What is the concentration of the Mg2 ion in solution when [CO3-2] = 0.25M given that the Ksp= 6.82 x 10-6 for the following reaction MgCO3-------->Mg +. CO32- Chemistry - DrBob222, Friday, November 11, 2011 at 5:34pm Ksp = (Mg^2+)(CO3^2-) Substitute 0.25M

    asked by Monique on November 12, 2011
  14. Physics

    A car travelling with constant acceleration increases its speed from 10 m/s to 50 m/s over a distance of 60 m . how long does this take? a. 2 seconds b. 4 seconds . Data : Avg Velocity = 10 + 50 / 2 = 30m/s Distance = 60 meter time = ? Solution : S= V x T

    asked by Shahab Mirza on July 12, 2015
  15. MaTh

    -5g - 6 for g= -2 4 16 10 -13 write an algebraic expression for the sum of 3 coins and c coins c+3 c/3 3c c-3 what value of x is a solution to the equation x-2=16 14 18 21 12 z/-12=-5 7 -60 -17 60 estimate the solition of the equation x-8.1=5.3 to the

    asked by AABBCC on October 20, 2015
  16. geometry

    I am not a student, I am a parent trying to help my son. I understand why you do not want to solve the questions, but can you please help me set them up correctly so I can try? h = -16t(exponent 2) + 60t where t is the time in seconds. A) Factor the

    asked by KP1 on October 5, 2016
  17. Chemistry

    How much of each of the following substances would you add to water to prepare 1.90 L of a 0.15 M solution? (a) H2SO4 from "concentrated" (18 M) sulfuric acid mL (b) HCl from "concentrated" (12 M) reagent mL (c) NiCl2 from the salt NiCl2·6 H2O g (d) HNO3

    asked by Anonymous on January 28, 2015
  18. chemistry Please Help Dr.BOB

    Complete hydrolysis of 25 mM ethyl acetate in an enzyme (i.e., esterase)-catalyzed reaction is carried out in a 40 mM NaCl solution buffered by 0.2 M Tris-Cl, pH 9.1. What is the pH at the end of the reaction? (For Tris base, which is the abbreviation for

    asked by Kim on February 7, 2011
  19. Chemistry

    Consider the following buffer equilibrium: HF (high concentration) + H2O H3O+ (low concentration) + F- ( high concentration) Using Le Chatelier's Principle, explain what happens to the pH of the buffer solution when a small amount of NaOH is added.

    asked by sh on June 3, 2010
  20. Analytical Chemistry

    How do I find the mass of KHP? 0.5050 grams of KHP was used and placed into a 250mL volumetric flask and diluted to the mark with distilled water. 50.00mL of this KHP solution was placed in a 250mL beaker. It took 14.75mL of 0.0067M of NaOH to reach the

    asked by Linda on July 20, 2011
  21. Chemistry

    The neutralization of H3PO4 with KOH is exothermic. H3PO4(aq) + 3KOH(aq) -> 3H2O(l) +K3PO4(aq) +173.2KJ 70.0 mL of 0.207 M H3PO4 is mixed with 70.0 mL of 0.620 M KOH initially at 21.87 °C. Predict the final temperature of the solution if its density is

    asked by Sally on January 24, 2013
  22. physics

    a sluice gate consists of a quadriant of a circle of radius 1.5m pivoted at its center 0. When the water is level with the gate, calculate the magnitude and direction of the resultant hydrostatic force on the gate and the moment required to open the

    asked by shu on January 13, 2016
  23. Statistics

    Waiting times to receive food after placing an order at the sandwich shop follow an exponential distribution with a mean of 46 seconds.? Calculate the probability a customer waits: a.) Less than 26 seconds b.) More than 105 seconds c.) Between 38 and 60

    asked by Terrance on October 19, 2014
  24. Chemistry

    At 80 degrees Celsius, the vapor pressure of pure liquids x, y and z are 385, 190 and 66 mm Hg. what pressure must be exerted on the surface of the solution containing one mole of x, three moles of y, and two moles of z for the boiling point to begin at 80

    asked by Angela on August 23, 2013
  25. Math

    A two population model is satisfied by a system of differential equations given by, V(x,y) = (ax,by)^T The general solution of the system of differential equations has x = áe^at for some constant á. The parameter t can be eliminated and we can express y

    asked by Anonymous on August 25, 2012
  26. College Chemistry

    Part a: What mass of solid CuCL2 is required to prepare 450.0mL of 0.125M CuCl2 solution?? Part B: What are the concentrations of Cu +2 ions and Cl- ions in the above solutions. I understand part a, and got the right answer. i need help understanding part

    asked by James on March 30, 2010
  27. Chemistry

    At 80 degrees Celsius, the vapor pressure of pure liquids x, y and z are 385, 190 and 66 mm Hg. what pressure must be exerted on the surface of the solution containing one mole of x, three moles of y, and two moles of z for the boiling point to begin at 80

    asked by Angela on August 23, 2013
  28. Math 133

    when the volume of a cube is given by V=S3, where S, is the lenght of a side. Find the lenght of a side of a cube if the volume is 500 cm3. And round the answer to three decimal places. can you solve this problem and show all steps with the solution?

    asked by Robert on July 11, 2010
  29. Chemistry

    What is the mass of MgCl2 required to make 500mL if 1.200 M of MgCl2 Solution? I'm having trouble figuring out what the equation looks like. I believe the answer is 57.127g but if so i would like to know why. I did (1.200M*.500mL)/1000* mass of MgCl2. How

    asked by Lemi on March 13, 2016
  30. math

    Lena bought a total of 20 postcards. She bought 6 more large poscards than small. Write a system of equations that represents the postcards Lena purchased. Solve the system by substitution. Interpret the solution.

    asked by Jane on November 26, 2012
  31. Chemistry

    Phosphoric acid, H3PO4(aq), is a triprotic acid, meaning that one molecule of the acid has three acidic protons. Estimate the pH, and the concentrations of all species in a 0.250 M phosphoric acid solution. [H3PO4] = ? [H2PO4^-] =? [HPO4^2-]=? [PO4^3-]=?

    asked by Anna on March 5, 2015
  32. physics

    Consider a charge of +2.0 C placed at the origin of an X-Y co-ordinate system and a charge of -4.0 C placed 40.0 cm to the right. Where must a third charge be placed – between the charges, to the left of the origin, or beyond the second charge –

    asked by matin on May 15, 2012
  33. chemistry(Please check)

    1) In comparing the phase diagram for water with that of a solution of sugar in water, all of the following decrease except a) the vapor pressure b) the boiling point c) the freezing point d) the triple point I chose the boiling point as the answer. Is

    asked by Hannah on February 10, 2012
  34. Math

    Julie is conducting an experiment where she placed 29.5 mL of water in a calorimeter at 15.0 °C. Then, 2.4 g of A (molar mass = 48.0 g/mol), also at 15.0°C, is added to the water in the calorimeter and the temperature of the solution increases to 28.0

    asked by Kelly on October 5, 2014
  35. physics

    Solution of:An air plane ABC R=250m (x=30) the speed of the meachine is 450Km/h in A determine the accelartion supported by the pilot in A and the tangential accelartion is 10m.s determine the speed in B if the tangential accelaration is constant

    asked by Dani on January 22, 2013
  36. chemistry

    In a standardization titration involving hydrochloric acid and sodium carbonate, a student recoirded the following results for the volume of hydrochloric acid used against 10.00mL of the sodium carbonate solution : 15.60; 14.50; 14.70 aqnd 14.20. If the

    asked by mije on October 24, 2015
  37. chem

    When 0.5mol of a certain ionic substance is dissolved in 1.0kg of water, the freezing point of the resulting solution is -3.72 ∘ C .(Freezing point depression of water is -1.86 kgwater molsoluteparticles ). How many ions does the substance give when it

    asked by dakota on March 26, 2015
  38. chemistry

    In acidic solution MnO4- oxidizes H3AsO3, a weak acid, to H3AsO4, a weak acid, and is reduced to Mn2+. Write the balanced net ionic equation for this reaction. How many H+ are there in the balanced equation

    asked by faith on October 9, 2010
  39. algebra

    A fish can swim 45 miles downriver in the same amount of time that it can swim 27 miles upriver. Solve for the speed of the current if the speed of the fish is 12 mph in still water. Show all of your work and explain your solution.

    asked by Anonymous on April 30, 2017
  40. Math

    Sam measured the out side of his vegetable garden.The sides measured 6 feet, 3feet, 6feet, and 3 feet.How much fencing does sam need to put a fence around the whole garden?Show two different methods of finding the solution.

    asked by Rashida on July 25, 2012
  41. Chemistry

    How can I make various concentrations of CuSO4? I know that to make 0.1M you would fill the copper solution up to 10mL in the graduated cylinder and then add water to the rest..but how can you prepare a 0.01M? 0.001? 0.0001?..........using water and

    asked by Anonymous on January 6, 2014
  42. Chemistry

    The hydroperoxide ion, HO2– (aq), reacts with permanganate ion, MnO4– (aq) to produce MnO2 (s) and oxygen gas. Balance the equation for the oxidation of hydroperoxide ion to O2(g) by permanganate ion in a basic solution.

    asked by Onye on March 4, 2018
  43. Mat 116 Final

    Is it true when the problem says solve x= then it is one number, or fraction. The test does say below where it is looking for an answer will say type integer, or fraction. Then I get myself confused when it says 7x = -56 I figured this is dividing -56 by 7

    asked by Loren on April 11, 2010
  44. chemistry ------ flame test-------------

    Did the nitrate ion effect the color emission of the solution ? how did you decide ? my answer: No , because The nitrate ion is the oxidizing agent in the compound without it you could not burn the chemicals and you could not produce a spectrum so there

    asked by Maria on October 11, 2012
  45. Chemistry

    A solid nonelectrolyte with a mass of 11.32g is dissolved in 115.00g of water. The observed freezing point of the solution is-3.44 degrees C. Given Kf of water=1.86 degrees C/m, what is the molar mass of the unknown solid?

    asked by Ceamus Angelina on May 16, 2018
  46. Math

    1) What is the dimension of AB given A is a 5 × 6 matrix and B is a 6 × 3 matrix? for the second questions, it is a fill in a blank question. 2) A point of intersection of the graphs of the equations of a system is a ? of the system. the ? is where one

    asked by anonymous on March 31, 2019
  47. chemistry

    Suppose a solution containing 3.50g of Na3PO4 is mixed with an excess of Ba(NO3)2. how many grams of Ba2(PO4)2 can be formed. 2-Na3PO4 +3-Ba3(NO3)2= 1-Ba3(PO4)2 + 6-NaNO3.(Balanced equation)

    asked by Kerry on March 8, 2010
  48. PRE - CALCULUS

    Use Gaussian elimination to find the complete solution to the system of equations, or state that none exists. Show your work. 4x-y+3z = 12 x+4y+6z =-32 5x+3y+9z = 20 ...... I NEED HELP WITH THE OTHER TWO PLEASE :) 4 -1 3 | 12 
1 4 6 | -32 
5 3 9 | 20 1

    asked by Ciara on April 17, 2015
  49. chmisrty

    when a solution of Iron (II)ammonium sulfate was mixed with K4FE(CN)6, the precipitate was initially white but turned blue upon exposure to air. what happen to the Iron(II)ionwhen the precipitate turned blue

    asked by beth on January 25, 2013
  50. MATH

    Jenny is running an experiment for organic chemistry class. She needs exactly 100 ml of 70% hydrochloric acid, but the lab only has 90% and 40% solutions. How much of each solutions does she need to mix in order to obtain 100 ml of 70% hydrochloric acid

    asked by Sara on April 5, 2017
  51. math

    Posted by question on Wednesday, July 22, 2009 at 4:56pm. solve 5/8x + 1/16x=7/16+= the solution is x=___ Responses math - Mr. L, Wednesday, July 22, 2009 at 7:23pm 5/8x is the same as 10/16x That should help my final answer would be 7/27 do i have it

    asked by question on July 22, 2009
  52. Chemistry

    I need to find the pH of a 500 mL solution of pure water after adding 33.0 mg of H2SO4 and 18.0 mg of HCl. Please help! So far I have tried to find the moles of 33.0mg of H2SO4 and got 3.24. Then I calculated pH by multiplying the subscript of H (2) by the

    asked by Nicole on November 27, 2016
  53. Chemistry Help

    The most effective buffer solutions have equal concentrations of salt and acid (or base). Find the pH of a buffer solution with equimolar concentrations of: (a) HCOOH and NaCOOH (Ka = 3.5 x 10-4 for HCOOH) (b)CH3NH2 and CH3NH3Cl (Kb = 3.7 x 10-4 for

    asked by Luke on February 23, 2017
  54. AP chem

    This is part of a marathon problem, we have to identify the five compunds of H, N, and O described below. For each compound, I have to write a Lewis structure that is consistent with the information given. a.) All the compunds are electrolytes, although

    asked by Corey on November 7, 2007
  55. AP chem

    This is part of a marathon problem, we have to identify the five compunds of H, N, and O described below. For each compound, I have to write a Lewis structure that is consistent with the information given. a.) All the compunds are electrolytes, although

    asked by Corey on November 7, 2007
  56. chemistry 11

    i did a lab on separation of salt and sand. the initial mass that my teacher gave me was the stock mixture that was: salt= 54.79g; sand= 97.90g. after the experiment my mass were as follow: salt= 1.35g; sand= 3.17g. question #1 was asking about the %

    asked by annon on October 13, 2016
  57. science(chem 11)

    did a lab on separation of salt and sand. the initial mass that my teacher gave me was the stock mixture that was: salt= 54.79g; sand= 97.90g. after the experiment my mass were as follow: salt= 1.35g; sand= 3.17g. question #1 was asking about the %

    asked by Annon on October 14, 2016
  58. chemistry 11

    i did a lab on separation of salt and sand. the initial mass that my teacher gave me was the stock mixture that was: salt= 54.79g; sand= 97.90g. after the experiment my mass were as follow: salt= 1.35g; sand= 3.17g. question #1 was asking about the %

    asked by Annon on October 14, 2016
  59. Algebra

    1.What is the simplified form of the following expression? 13[6^2€(5^2-4^2)+9] A.169 B.585*** C.181 D.26 2.What is the simplified form of the expression? 6xyz/2xz A.3 B.3y C.3xyz*** D.3x^2yz^2 3.In a football game. A running back ran for -7 and -5 on

    asked by GummyBear on August 31, 2015
  60. chemistry

    Calculate the enthalpy of reaction for the combustion of ethene. Express the enthalpy of reaction calculated in question above as a molar enthalpy of reaction per mole of carbon dioxide.

    asked by shyanne on January 8, 2013
  61. calculus

    The line y+x=9 intersects the curve y=x^2-2x+3 at the points P and Q . (a) Find the coordinates of P and Q . (b) Sketch the line and the curve on the same set of axes. (c) Calculate the area enclosed by the line and the curve.

    asked by kchik on December 11, 2012
  62. Chemistry

    Enthalpy changes: H2O2(l) ----> H2O(l) + 1/2P2(g) delta H= -94.6kJ H2(g) + 1/2O2(g)----> H2O2 delta H= -286.0kJ Calculate the value on delta H for the reaction: H2(g) + H2O2(l)----> 2H2O(l)

    asked by Megan on May 19, 2012
  63. chemistry

    To extract gold from its ore, the ore is treated with sodium cyanide solution in the presence of oxygen and water. 4 Au(s) + 8 NaCN(aq) + O2(g) + 2 H2O(l) 4 NaAu(CN)2(aq) + 4 NaOH(aq) Determine the mass of gold that can be extracted if 27.4 g sodium

    asked by r on February 3, 2010
  64. chemistry

    To extract gold from its ore, the ore is treated with sodium cyanide solution in the presence of oxygen and water. 4 Au(s) + 8 NaCN(aq) + O2(g) + 2 H2O(l) 4 NaAu(CN)2(aq) + 4 NaOH(aq) Determine the mass of gold that can be extracted if 27.4 g sodium

    asked by r on February 3, 2010
  65. Math

    A local computer center charges non-members $5.00 per session to use the media center. If you pay a membership fee of $25, you pay only $3 per session. Write an equation that can help you decide whether to become a member then solve the equation and

    asked by Amber Olander on February 3, 2009
  66. chemistry

    Dissolve 1.5g of an unknown salt into 37g of water and find that the new vapor pressure at 75C is 277 torr. What is the Molar Mass of the unknown? How many grams of the unknown would have to be used in 100ml of water to make a 11.5% solution by mass of the

    asked by regina on December 5, 2010
  67. algebra

    in solving the equation (x +2)(x - 2) = 32 eric stated the solution to be x + 2 = 32 => x = 30 or x- 2 = 32 => x = 34. however at least one of these solutions fails to work when plugged back into the equation. why is that? please help eric to understand

    asked by Theresse on September 29, 2012
  68. Chemistry

    The vapor pressure of pure water at 30C is 31.8Torr. What is the vapor pressure of a solution of NaCl dissolved in water when the mole fraction of NaCl is 0.111? I am wondering if this would be correct. 0.11*31.8= 3.5 Torr Is there another way to solve

    asked by Christopher on January 29, 2017
  69. Physics

    Two waves in one string are described by the wave functions y1 = 2.90 cos (3.80x - 1.50t) y2 = 3.90 sin (4.80x - 2.10t) a) where y and x are in centimeters and t is in seconds. Calculate the superposition of the waves y1 + y2 at the points x = 1.50, t =

    asked by Hau on November 16, 2012
  70. physics

    An artificial sattelite as a mars of 600 kg and moving towards moon.calculate its kinetic energy and potential energy in mJ relative to the earth when it is 50 km from launching and moving at 2500 km/h take acceleration of earth gravitational field as 790

    asked by vishal vegad on February 15, 2013
  71. chemsitry

    hi I need help with this question please. 1. consider the decomposition of N2O5 in carbon tetrachloride(ccl4) at 45c 2N2O5(soln)-> 4NO2(g)+ O2(g) The reacion is first order in N2O5, with the specific rate constant 6.08*10^-4 per second.calculate the

    asked by hrithik on December 8, 2009
  72. physics

    A hammer weighing of 1 kg moving with the speed of 10 m/s strikes the head of the nail driving it 10 cm into wall. Neglecting the mass of the nail, calculate: 1) The acceleration during the impact 2) The time interval during the impact 3) The impulse

    asked by Anonymous on June 25, 2017
  73. physics

    Consider a block on an incline plane. The coefficients of static and kinetic friction between the block and the incline are µs = 0.353 and µk = 0.31. Calculate the critical angle θc, where the block just begins to slide. Answer in units of ◦. The

    asked by I dont like physics on November 24, 2015
  74. physics

    Using Coulomb's Law, calculate the force of repulsion between a positive charge of 110 Coulombs and another positive charge of 220 coulombs separated by a distance of 2 meters. Use scientific notation. (Hint: use the proportionality constant)

    asked by LL on June 17, 2012
  75. chemistry

    Calculate the ΔH of reaction for: C2H4(g) + H2O(l) = C2H5OH(l) if the ΔH of formation for C2H4(g), H2O(l) and C2H5OH are +52, -286 and -278 kJ/mol, respectively? Enter a numerical value below and be sure to include a minus sign if needed. The error

    asked by danny 16 on January 31, 2015
  76. Physics

    A 250kg box is pushed horizontally with a force of 750 Newtons. If the coefficient of friction is 0.25, calculate the net acceleration of the crate. I am confused how I am to find the net acceleration. I solved to find FN and FG is 2452 N is that correct

    asked by rina on November 24, 2014
  77. Math

    a small plane flies due south with a speed of 112 m/s while a tailwind blows due south at 31 m/s. Draw and label a vector diagram and calculate the magnitude and direction of the plane's resultant velocity

    asked by Penn on September 25, 2016
  78. Chemistry

    If the equilibrium constant K equals .05, and the reaction C3H8=C3H6 + H2 (all gases), starts with pure C3H8 and is allowed to reach equilibrium at 200 K at a total pressure of 2 bar. Calculate the partial pressure of H2 at equilbirum.

    asked by Anonymous on February 14, 2014
  79. Math

    1)AP has U6=12.5 and U19=32 a+5d=12.5 (&) a+18d=32 (2) (2)-(1), d=1.5 therefore, a=5 (a)What is the nth term?Tn=5+(n-1)1.5 (b)What is the sum of 4 terms between U10 and U13 inclusive? 2)Un=1/2^n-3 (a)What is the nature of this sequence? (b)Calculate the

    asked by Anonymous on April 19, 2008
  80. chemistry

    Data: SO2(g)+ 1/2O2(gas)forms SO3(g)Delta H = -99.1 kJ. Given the above data, calculate the enthalpy change when 89.6 g of SO2 is converted to SO3. Is this a grams to moles conversion or what? I can't find any examples of this type of calculation.

    asked by lavonne on October 27, 2010
  81. biology

    A 28.0-g sample of ice at -18.0°C is mixed with 124.0 g of water at 85.0°C. Calculate the final temperature of the mixture assuming no heat loss to the surroundings. The heat capacities of H2O(s) and H2O(l) are 2.08 and 4.18 J/g · °C, respectively, and

    asked by layla on October 15, 2011
  82. maths

    A paving block is is in the shape of a prism, the area of it' cross section being 154cm^2.The prism i 17cm long ad the material from whih it is made has a density of 2.2g/cm^3. Calculate the mass of the paving block. Please can you tell me the method

    asked by chelsea on June 6, 2009
  83. chemistry

    At temperatures above 930 ∘C, PbO reduces PbS to form metallic lead (Pb). The byproduct of the reaction is SO2. Calculate the amount of lead produced (in kg) when a reactor is charged with 887.0 kg of PbS and 1330 kg of PbO.

    asked by pls check it..urgent(limiting reagent) on January 13, 2013
  84. physics

    an aeroplane has a mass of 15 tonnes. At cruising speed,air flows over the top of it's wing at 150 m/s and under the wing at 120m/s. Calculate the pressure in difference between the top and the bottom of the wing and the surface area underside the wing

    asked by Kay on November 25, 2016
  85. chemistry - HELP!

    The equilibrium constant, Kc, for the reaction A(g) + B(g) AB(g) is 115 at 25 degrees C. If 1.580 x 10^(‐1) mol of A and 4.721 x 10^(‐5) mol of B are introduced into a 1.00 liter vessel at 25 degrees C, calculate the equilibrium concentration of all

    asked by Sheri on October 11, 2015
  86. Chemistry

    A 13.0-g sample of ice at -13.0°C is mixed with 112.0 g of water at 80.0°C. Calculate the final temperature of the mixture assuming no heat loss to the surroundings. The heat capacities of H2O(s) and H2O(l) are 2.08 and 4.18 J/g · °C, respectively, and

    asked by Katrina on February 13, 2011
  87. Chemisrty

    A 10.0 g sample of ice at -14.0°C is mixed with 124.0 g of water at 81.0°C. Calculate the final temperature of the mixture assuming no heat loss to the surroundings. The heat capacities of H2O(s) and H2O(l) are 2.08 and 4.18 J/g°C, respectively, and the

    asked by Nancy on December 9, 2012
  88. Physics

    An ion beam has a cross-sectional of 2.5 mm^2 and the charge delivered by it to a target can be expressed as q(t)=(.12 C/s^3)t^3 + (.24 C/s^2)t^2 - .45 C. Calculate the current density in the beam at t = 3.0 seconds. I used an integral from 0 to 3s. and

    asked by Zabe on July 4, 2016
  89. chemistry

    An element has ccp packing with a face-centered cubic unit cell. Its densiry is 2.70E3 kg/m3 and the unit cell volume is 6.64E-29 m3. Calculate the molar mass (g/mol) of the element to 3 significant figures.

    asked by roxanne on February 4, 2008
  90. Physics - Calculating work required

    Two equipotential surfaces are shown. If Va = -5V and Vb = -15V, find the work needed to move a -2μC charge from A to B along the indicated path. - First of all, does the path of the charge going from A to B matter or can I just calculate using the

    asked by Kid on February 16, 2017
  91. chemistry

    An element has ccp packing with a face-centered cubic unit cell. Its densiry is 2.70E3 kg/m3 and the unit cell volume is 6.64E-29 m3. Calculate the molar mass (g/mol) of the element to 3 significant figures.

    asked by roxanne on February 4, 2008
  92. Physics

    A 2600 kg truck traveling at 72 km/h slams on the brakes and skids to a stop. The frictional force between the truck and the road is 8200 N. Calculate the mechanical work required to stop the truck and the distance the truck travels before stops.

    asked by Jack Hill on July 18, 2012
  93. MATH!

    What initial investment would I have to make at 6% per year compounded semi-annually in order to end up with $1,000,000 in 29 years if I didn't make any monthly contributions. a) estimate using the rule of 72. Explain how you came up with your estimate. b)

    asked by Madeline on August 6, 2013
  94. Physics

    A certain insect’s wing has been shown to deflect a distance 14.8 mm under a force of 0.19 N applied to the end of the wing. (a) If the wing is assumed to behave as an ideal spring, calculate the force constant in N/m. (b) At this deflection, how much

    asked by Sahar on April 21, 2016
  95. Chemistry

    A gas is confined to a cylinder under constant atmospheric pressure, as illustrated in the following figure. When the gas undergoes a particular chemical reaction, it absorbs 827 J of heat from its surroundings and has 0.66 kJ of P−V work done on it by

    asked by Tanner on October 14, 2015
  96. Math 209

    If a cylindrical container has a volume of cubic feet, then its surface area S in square feet (excluding the top and bottom) is given by S = s=(2π )/r where r is the radius of the cylinder. (a) Calculate S when r =1/2 foot (b) What happens to this surface

    asked by DeLynn Stewart on July 9, 2011
  97. physics

    A vehicle accelerates from rest with a unifrom acceleration of 0.5m/s^2 up to a velocity of 36km/h.It travels at constant velocity for 1km,the brakes are then applied and it comes to rest in 20s.Calculate the total distance travelled and the total time

    asked by Prince y.Alpha on August 14, 2015
  98. chemistry

    A 13.0-g sample of ice at -13.0°C is mixed with 105.0 g of water at 78.0°C. Calculate the final temperature of the mixture assuming no heat loss to the surroundings. The heat capacities of H2O(s) and H2O(l) are 2.08 and 4.18 J/g · °C, respectively, and

    asked by layla on October 15, 2011
  99. physics

    Using Coulomb's Law, calculate the force of repulsion between a positive charge of 110 Coulombs and another positive charge of 220 coulombs separated by a distance of 2 meters. Use scientific notation. (Hint: use the proportionality constant)

    asked by LL on June 17, 2012
  100. Physics

    The respective charges on three identical metal spheres (q1, q2 and q3) are ̶ 16.9 µ C, 5.60 µ C and 2.6 µ C. The spheres are brought together so that they touch each other, and are then separated and placed on the x and y axes. Calculate the net

    asked by Ellen on April 30, 2018

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