Questions Asked in 2007

Most Popular Questions of 2007

  1. CHEM

    Help on part "c": The forensic technician at a crime scene has just prepared a luminol stock solution by adding 19.0g of luminol into a total volume of 75.0mL of H2O. a)What is the molarity of the stock solution of luminol? anwer I got: molarity of luminol

    asked by K on October 18, 2007
  2. Physics

    A helicopter is ascending vertically with a speed of 5.20 m/s. AT the height of 125m above the earth, a package is dropped from a window.How much time does it take for the package to reach the ground. ****Note: Please show the steps.

    asked by Bunty on September 15, 2007
  3. CHEM

    What are the expected bond angles in ICl4+ (or) ICl_4^+ ?? I think that I have the stucture drawn correcty: I is the central atom with one lone pair above it. I then have the Cl's with 6dots around them & then bonded, singly, to the "I". Two "Cl's" go

    asked by K on November 26, 2007
  4. chemistry

    how do i write a net ionic equation for Lead (II) Nitrate and Sodium Carbonate react to form Lead Carbonate and Sodium Nitrate??

    asked by caren on December 11, 2007
  5. CHEM

    For a molecule of fluorous acid, the atoms are arranged as HOFO. What is the formal charge on each of the atoms? Enter the formal charges in the same order as the atoms are listed. For this question I tried entering: +1,-2,+3,-2 and it was wrong...as was:

    asked by K on November 26, 2007
  6. chemistry

    Is NH4+ a polar or nonpolar bond?

    asked by Lin on November 30, 2007
  7. Chemistry

    What is the pressure (in atmospheres) of the gas inside the container connected to an open-end, mercury-filled manometer as shown in the picture? The atmospheric pressure is 0.95atm. l----l | (G) l | l - --- l Hg l Hg *18cm - - --- Hg Hg HgHgHgHg what

    asked by leo on October 21, 2007
  8. physics.

    A 20.0 kg cannon ball is fired from a cannnon with muzzle speed of 1000 m/s at an angle of 37.0 with the horizontal. A second ball is fired at an angle of 90.0. Use the conservation of energy principle to find a] the maximum height reached by each ball and

    asked by Jean on March 15, 2007
  9. Calculus

    An equation of the line tangent to the graph of y=(2x+3)/(3x-2) at the point (1,5) is...do I take the derivative of y=(2x+3)/(3x-2) to find the slope and then plug that into y-5=m(x-1)?

    asked by Anonymous on November 18, 2007
  10. Physics

    A hollow, spherical shell with mass 2.00 kg rolls without slipping down a slope angled at 38.0 degrees. (a) Find the acceleration, the friction force, and the minimum coefficient of fricition needed to prevent slipping. You will find the moment of inertia

    asked by Karla on March 27, 2007
  11. **CHEM**

    Arrange the following elements in order of decreasing atomic radius: Cs, Sb, S, Pb, Se *(list from largest to smallest...or..."the correct ranking cannot be determined") ***I think the answer 'should be', from largest to smallest: ***Cs, Pb, Sb, Se,

    asked by K on November 13, 2007
  12. math

    Can somebody please help me with this problem? This is the index-„³ 5 6^-5 The radical sign did not show, but the problem is: 5 is the index (outside the radical sign and then 6 is squared to the -5th power (inside the radical sign is under the radical

    asked by Larry on January 1, 2007
  13. CHEM

    Which statement best describes the polarity of SF_4Cl_2?? (or: SF4Cl2, if that helps more) 1. Always polar. 2. Always nonpolar. 3. Depending on the arrangement of outer atoms, this molecule could be polar or nonpolar. & how can you tell for certain??? I

    asked by K on November 26, 2007
  14. Physics

    A wheel with rotational inertia I is mounted on a fixed, fricitonless axle. The angular speed w of the wheel is inccreased from zero to w_f in a time interval T. 1: What is the average net torque on the wheel during the time interval, T? a) w_f/T b)w_f/T^2

    asked by Tammy on March 25, 2007
  15. Statistics

    A sign on the gas pump of a certain chain of gasoline stations encourages customers to have their oil checked, claiming that one out of every four cars should have its oil topped up. What is the probability that exactly 3 of the next 10 cars entering a

    asked by Matt on February 10, 2007
  16. CHEM

    The mass of a golf ball is 45.9g. If it leaves the tee with a speed of 72.0 m/s, what is its corresponding wavelength? Express your answer numerically in meters. Would the correct answer be: lambda=h/mv lambda=6.626*10^-34/(45.9g)(72.0m/s)

    asked by K on November 5, 2007
  17. Chemistry - solubility

    Arrange the following compounds in order of increasing solubility in water: * O2 * LiCl * Br2 * CH3OH Like dissolves like; that is, polar compounds usually are soluble in water and non-polar compounds are not soluble in water. From that description, make

    asked by Belinda on January 2, 2007
  18. CHEM

    The electron from a hydrogen atom drops from an excited state into the ground state. When an electron drops into a lower-energy orbital, energy is released in the form of electromagnetic radiation. Part A: How much energy does the electron have initially

    asked by K on November 4, 2007
  19. Chemistry

    What volume of O2 is required to react with excess CS2 to produce 4.0L of CO2 Assume all gases at STP. Not sure what I am doing wrong, but the answer I am getting is not one of the answers. 4L/X mole=22.4 L/1 mole ===>.1786 mols Balanced equation: O2 + CS2

    asked by T on December 13, 2007
  20. Math

    Why Does The President Put Vegetables in His Blender? P.S.: It's puzzle 163 HELP!!!!!!!!!

    asked by Dorina on December 9, 2007
  21. Physics

    A cylinder is fitted with a piston, beneath which is a spring, as in the drawing. The cylinder is open at the top. Friction is absent. The spring constant of the spring is 4100 N/m. The piston has a negligible mass and a radius of 0.023 m. (a) When air

    asked by Mary on April 24, 2007
  22. Physics

    One end of a uniform meter stick is placed against a vertical wall. The other end is held by a lightweight cord that makes an angle, theta, with the stick. The coefficient of static friction between the end of the meter stick and the wall is 0.390. A. what

    asked by Karla on April 3, 2007
  23. Physics

    The four tires of an automobile are inflated to an absolute pressure of 2.0*10^5 Pa. Each tire has an area of 0.024m^2 in contact with the ground. Determine the weight of the automobile. Pressure*area= force. There are four tires.

    asked by Sarah on May 10, 2007
  24. Chemistry II

    C4H4 (g) + 2 H2 (g) --> C4H8 (g) Combustion reactions involve reacting a substance with oxygen. When compounds containing carbon and hydrogen are combusted, carbon dioxide and water are the products. Using the enthalpies of combustion for C4H4 (-2341

    asked by Jayd on May 20, 2007
  25. Physics

    Thanks for any help :) Four 20 ohm resistors are connected in parallel and the combination is connected to a 20V emf device. The current is: A) 0.25A B) 1.0 A C) 4.0 A D) 5.0 A E) 100 E Parallel circuits: I know that the voltage is 20V and the Resistance

    asked by susane on March 15, 2007
  26. Science-Enr. Phys.

    A box of books weighing 325 N moves at a constant velocity across the floor when the box is pushed with a force of 425 N exerted downward at an angle of 35.2 degrees below the horizontal. Fink Mu,k between the box and the floor. There have been several of

    asked by Sara on February 25, 2007
  27. CHEM-last part prob.

    Aluminum reacts with chlorine gas to form aluminum chloride via the following reaction: 2Al(s) + 3Cl2(g) -> 2AlCl3(s) You are given 19.0g of aluminum and 24.0g of chlorine gas. a)If you had excess chlorine, how many moles of of aluminum chloride could be

    asked by K on October 16, 2007
  28. physics--drwls

    A record of travel along a straight path is as follows: 1. Start from rest with constant acceleration of 2.77 m/s^2 for 15 s 2. Constant velocity for the next 2.05 min 3. Constant negative acceleration -9.47 m/s^2 for 4.39 s. (a) What was the total

    asked by Star on September 7, 2007
  29. physics

    A ball is attached to a string with length of L. It swings in a horizontal circle, with a constant speed. The string makes an angle (theta) with the vertical, and T is the magnitude of the tension in the string. 1)Determine the Mass of the Ball.

    asked by ken on November 4, 2007
  30. Exponents-word problem

    A culture starts at 8600 bacteria. After one hour the count is 10,000. Find a function that models the number of bacteria n(t) after t hours. The answer is n(t) = 8600e^.1506t Where does this 0.1506 come from? Thanks. n(t) = 8600 e^(kt), where k is an

    asked by Jen on February 16, 2007
  31. riting/spelling

    wat duz liberal meen? sorrey about mi spelling. I just need too kno fore my english class.

    asked by freak show on November 20, 2007
  32. Physics;Help!!!!!!

    There is apparently no one online who can help with physics questions right now. Please check back later to see if a physics teacher has addressed your question. Multiple posts won't get faster answers. Thanks. =) The question is in the first question

    asked by Writeacher on June 7, 2007
  33. Chemistry

    Why is CH3I have a higher boiling point than CH3Cl? I thought, since Cl is more electronegative, it withdraws more electron density to its part and hence increase dipole movement within the atom and hence, requiring more energy to split them up and that

    asked by Vic on August 24, 2007
  34. CHEM

    My balanced equation is: a) 2C8H18(g) + 25O2(g) -> 16CO2(g) + 18H2O(g) b) 0.290 mol of octane is allowed to react with 0.670mol of oxygen. Which is the limiting reactant? (((Which I found Oxygen to be the limiting reactant.))) I do not understant how to

    asked by K on October 15, 2007
  35. Calculus

    A spinner is used for which it is equally probable that the pointer will land on any one of six regions. Three of the regions are colored red , two are colored green, and one in colored yellow. If the pointer is spun twice, find the probability it will

    asked by John on December 10, 2007
  36. Physics

    If 500 J of work are required to carry a charged particle between two points with a potential difference of 40V, the magnitude of the charge on the particle is: a) 0.040 C b) 12.5 C c) 20C D) cannot be computed unless the path is give e) none of these My

    asked by susane on March 12, 2007
  37. Economics

    Questions: Are the following workers more likely to experience short-term or long-term unemployment? Explain. a. A construction worker laid off because of bad weather. b. A manufacturing worker who loses her job at a plant in an isolated area. c. A

    asked by Sarah on March 24, 2007
  38. Physics

    A robot probe drops a camera off the rim of a 239 m high cliff on Mars, where the free-fall acceleration is -3.7 m/s^2. a) Find the velocity with which the camera hits the ground. b) Find the time required for it to hit the ground. Ok so I'm not even sure

    asked by Lindsay on September 25, 2007
  39. Statistics

    Standard Normanl Drill: A. Find the number z such that the proportion of observations that are less than z in a standard Normal distribution is 0.8. B. Find the number z such that 35% of all observations from a standard Normal distribution are greater than

    asked by Devon on September 10, 2007
  40. AP chem

    A 0.345g sample of anhydrous BeC2O4, which contains an inert impurity, was dissolved in a sufficient water to produce 100ml of solution. A 20.0ml portion of the solution was titrated w/ KMnO4(aq). The balanced equation for the reaction that occurred is as

    asked by michelle on January 4, 2007
  41. physics

    A water slide is constructed so that swimmers, starting from rest at the top of the slide leave the end of the slide traveling horizontally. There is still a height between the surface of the water and the end of the slide. One person hits the water 5.00m

    asked by ajo on December 11, 2007
  42. chem

    3.0 mol sample of KClO3 was decomposed according to the equation 2KClO3 = 2KCl + 3 O2 How many moles of O2 are formed assuming 100% yield? is it 3 moles? I don't want to work through the details of this problem completely. Tell me what you don't understand

    asked by jill on July 17, 2007
  43. Chemistry

    I have a few question about an equilibrium lab we performed. Approximately .1 g of CoCl2 * 6H2O was mixed with 2 mL of 12 M HCl. The solution turned blue. Then, water was added and stirred into the solution in 2 mL incriments until no further color change

    asked by Kim on May 29, 2007
  44. physics

    a collapsible plastic bag contains a gluccose solution. If the average gauge pressure in the atery is 1.33x10^4Pa, what must be the minimum height h, of the bag in order to infuse gluccose into the artery? Assume that the specific gravity of the solution

    asked by Anonymous on December 16, 2007
  45. Chemisry

    what mass of protons would be required to just neutralize the charge of 1.0g of electrons? how do I answer this? You know the mass of an electron. Calculate how many are in 1 gram. You will need the same number of protons. Knowing the mass of a proton

    asked by Chris on February 8, 2007
  46. Physics- LOST!

    If the air temperature is the same as the temperature of your skin (about 30.0 C), your body cannot get rid of heat by transferring it to the air. In that case, it gets rid of the heat by evaporating water (sweat). During bicycling, a typical 70.0 kg

    asked by Jamie on December 3, 2007
  47. Somebody answer

    answer questions Ask a question. I have been working on the question for at least an hour. The question is: I have to spend 100 dollers and by 100 brains. Cow brains 5.00 Pigs 2.00 sheep 0.10 I have to buy one of each. I am very confused. Are teacher gave

    asked by dfsfd on April 1, 2007
  48. math

    You are reducing a map of dimensions 2 ft by 3 ft to fit to a piece of paper 8 in by 10 in. What are the dimensions of largest possible map that can fit on the page? I really don't know how to do this but so far I tried to make 2 proportions by changing

    asked by keisha on November 24, 2007
  49. Chemistry

    In a gas mixture of He, Ne, and Ar with a total pressure of 8.40 atm, the mole fraction of Ar is ________ if the partial pressures of He and Ne are 1.50 and 2.00 atm respectively. pHe = 1.50 atm. pNe = 2.00 atm. pAr = 8.40 atm - 1.50 - 2.00 = ?? mole

    asked by john on January 14, 2007
  50. physics

    A 650 kg weather balloon is designed to lift a 4600 kg package. What volume should the balloon have after being inflated with helium at 0 degrees celcius and 1 atm pressure to lift the total load? The buoyancy force must equal the weight lifted. Let V be

    asked by Anonymous on May 9, 2007
  51. Physics

    A spring has a force constant of 100N/m and an unstretched lenght of .07 m. One end is attached to a post that is free to rotate in the center of a smooth table. The other end is attatched to a 1 kg disc moving in uniform circular motion on the table,

    asked by Tammy on March 25, 2007
  52. Chemistry

    At 40 degrees Celsius, the value of Kw is 2.92 X 10^-14 a.) calculate the [H+] and [OH-] in pure water at 40 degrees celsius b.)what is the pH in pure water at 40 degrees celsius c.)if [OH-] is .18M , what is the pH

    asked by Rebekah on December 21, 2007
  53. stat

    Which of the following statements is true about the t-distribution with k degrees of freedom? i. the t-distribution is symmetric ii. the t-distribution with k degrees of freedom has a smaller variance than the t-distribution with k+1 degrees of freedom

    asked by Anonymous on May 2, 2007
  54. Chemistry

    a change in pressure would have the greatest effect on the solubility of a A. solid in a liquid B. gas in a liquid C.liquid in a liquid D.liquid in a solid in an aqueous solution of potassium chloride, the solute is A. Cl B. KCl C. H20 D. K B for the

    asked by Kat on March 26, 2007
  55. Chemistry

    Magnesium sulfate is often used it first aid hot-packs giving off heat when dissolved in water. When 2.00 g of MgSO4 dissolves in 15.0 mL of water (d= 1.00g/mL) at 25.0ºC, 1.51 kJ of heat is evolved. A) Write the balanced equation for this reaction. I

    asked by Chris on January 28, 2007
  56. College Physics

    A fisherman notices that his boat is moving uo and down periodically, owing to waves on the surface of the water. It takes 2.5 s for the boat to travel from its highest point to its lowest, a total distance of 0.62 m. The fisherman sees that the wave

    asked by Jen on October 26, 2007
  57. Chemistry

    At 1100 K, Kp=0.25 for the following reaction. 2SO2(g) + O2(g) (reversible arrows) 2SO3(g) What is the value of K at this temperature? This is what I have so far: I did Kc=0.25(1100(0.0821))^-1 and got Kc=0.00276. That is incorrect. Why? What did I do

    asked by Taasha on July 31, 2007
  58. physics!! plz answer me!

    A 0.15 kg baseball moving at +26 m/s is slowed to a stop by a catcher who exerts a constant force of -390 N. How long does it take this force to stop the ball? How far does the ball travel before stopping? plz plz plz help!!

    asked by julia on December 10, 2007
  59. CHEM

    A) a picture shows a container that is sealed at the top by a movable piston. Inside the container is a ideal gas at 1.00atm , 20.0 *C, and 1.00L. (The pic is of a 2L container which has a piston pushed downward to the 1L level. Under the piston, under the

    asked by K on October 28, 2007
  60. Gen chem II

    Calculate the work done when 50.0g of tin dissolves in excess acid at 1.00atm and 25 (degree in celsius) Sn(s)+2H(aq)----- Sn(aq) +H2(g) Assume ideal gas behavior The work done = (pressure)*(increase in volume) The increase in volume is due to the H2 gas

    asked by Farzan on March 5, 2007
  61. accounting

    List the following steps of the accounting cycle in their proper order a. Preparing the post closing trial balance b. postint the journal entries c. journalizing and posting adjusting entries d. preparing the adjusted trial balance e. journalizing and

    asked by shelly on October 16, 2007
  62. math

    if 12 counters are 3/4 of a set, what is the whole set of counters?

    asked by milan on December 6, 2007
  63. Chemistry

    Which radioactive sample would contain the greatest remaining mass of the radioactive isotope after 10 years? A. 2.0 grams of 198 Au B. 2.0 grams of 42 K C. 4.0 grams of 32 P D. 4.0 grams of 60 Co By the way the numbers next to the elements are their

    asked by Sanjay on March 3, 2007
  64. AP Chem

    A solution of potassium phosphate is mixed with a solution of calcium acetate. I am supposed to write a net ionic equation. Doesn't need to be balanced. Here is what I did: K3PO4(aq) + Ca(C2H3O2)2 --> KC2H3O2 + Ca3PO4 3K+ + PO4-3 + Ca+2 2(C2H3O2-) --> K+ +

    asked by Please check on October 3, 2007
  65. AP Chemistry

    (a)calculate the mass percent of carbon in the hydrated form of the solid that has the formula BeC2O4 X 3 H2O (s). I divided 24.02 g by 151.08 g and got .16, or 16%. is that correct? Also, I'm having trouble with this follow up question. When heated to 220

    asked by Patrick on September 19, 2007
  66. Physics

    A small first aid kit is dropped by a rock climber who is descending steadily at 1.3 m/s. After 2.5 s, what is the velocity of the first-aid kit, and how far is the kit below the climber? This problem seems like it should be easy, but I'm not sure which

    asked by Stephanie on September 30, 2007
  67. CHEMISTRY

    HOW CAN U TELL IF HNO3 +KNO3 IS A BUFFER SOLUTION A buffer solution must contain a weak acid and its conjugate base OR a weak base and its conjugate acid. HNO3 is a strong base and KNO3 is the salt of a strong base (KOH) and a strong acid (HNO3);

    asked by CANDY on February 27, 2007
  68. Statistics

    Thank you!! A survey of an urban university (population of 25,450) showed that 750 of 1100 students sampled attended a home football game during the season. What inferences can be made about student attendance at football games? Using the 99% level of

    asked by Jenny on December 19, 2007
  69. why is physics so hard??????

    a velocity vector of 40 degrees below the positive x-axis has a y-component of -10 m/s. What is the value of its x-component. I know the answer is 11.9 m/s. When I first tried it, I got 6.43 and then I just tried bunch of stuff and I got 11.9 but what I

    asked by apoorva on September 19, 2007
  70. Chemistry

    1)The chemical formula for aspirin is C9H8O4. What is the mass of 0.40 mol of aspirin? How would I find this? 2)The gram molecular mass of oxygen is 16.0 g right? 3)How would I find the mass, in grams, of 3.01 x 10^23 molecules of water? 1. Add the atomic

    asked by anonymous on July 31, 2007
  71. science

    in a baseball-hitting contest at the office picnic, five men participated named: Biff, Carl, Fred, Marty, and Tom. Their last names in alphabetical order are Jenkins, Keech, McNabb, Miller, and Winslow. The distance that each man hit the ball in feet are:

    asked by angie on September 26, 2007
  72. Science

    Would the objects with the following densities float, sink, or remain suspended in tap water?(water=1.0g/mL) a. 0.85g/mL_____________ b. 1.0g/mL _____________ c. 1.4 g mL_____________ d. 0.92g/mL_____________

    asked by Sonic on September 1, 2007
  73. Math Probabilities

    A bag contains 9 red chips and 12 blue chips. Two chips are selected randomly without replacement from the bag. What is the probability that the two chips are the same color? That would be the probability of two reds PLUS the probability of two blues. The

    asked by J on March 6, 2007
  74. physics

    A .100 kg meter stick is supported at its 40.0 cm mark by a string attached to the ceiling. A .700 kg mass hangs vertically from the 5.00 cm mark. A mass, m, is attached somewhere on the meter stick to keep it horizontal and in rotational and translational

    asked by Anonymous on December 4, 2007
  75. math

    5. A rubber ball dropped on a hard surface takes a sequence of bounces, each one 3/5 as high as the preceding one. If this ball is dropped from a height of 15 feet, what is the total distance it has traveled after it hits the surface the fifth time? The

    asked by Fidelia on May 31, 2007
  76. math

    what is the answer to the riddle "why is it good to play cards in a graveyard"

    asked by Anonymous on December 16, 2007
  77. Econ MC

    Two firms, A and B, each currently dump 50 tons of chemicals into the local river. The government has decided to reduce the pollution and from now on will require a pollution permit for each ton of pollution dumped into the river. The government gives each

    asked by Anonymous on March 6, 2007
  78. CHEM

    You are a researcher for a golf club manufacturer. You are given two identical looking cubes of a metal alloy. You are informed that they are made of the exact same material, but one is a crystalline, while the other is amorphous. It is your job to

    asked by K on November 28, 2007
  79. Physics

    When a block slides a certain distance down an incline the work done by gravity is 300 J. What is the work done by gravity if this block slides the same distance up the incline? a) 300 J b) zero c) -300 J d) It cannot be determined without knowing the

    asked by Tammy on March 26, 2007
  80. physics- torque

    1. Find the magnitude of the torque produced by a 3.0 N force applied to a door at a perpendicular distance of 0.25 m from the hinge. 2. A simple pendulum consists of a 3.0 kg point mass hanging at the end of a 2.0 m long light string that is connected to

    asked by Anonymous on January 13, 2007
  81. Physics HELP!!!!!!!!

    For the normal force in Figure 5.21 to have the same magnitude at all points on the vertical track, the stunt driver must adjust the speed to be different at different points. Suppose, for example, that the track has a radius of 3.1 m and that the driver

    asked by Mary on February 21, 2007
  82. statistics

    A police department reports that the probabilities that 0, 1, 2, and 3 burglaries will be reported in a given day are 0.50, 0.41, 0.05, and 0.04, respectively. Find the standard deviation for the probability distribution. Round answer to the nearest

    asked by darius on August 28, 2007
  83. Romeo and Juliet (English Literature)

    1. To what heavenly body does Romeo compare Juliet? Why is this so? 2. What does Juliet mean when she says to Romeo, "tis, but thy name that is my enemy?" 3. How is Romeo let to Juliet's home? 4. Is it difficult for Romeo to win Juliet's love? Why? 5. Why

    asked by Han on October 31, 2007
  84. Physics Question......many thanks

    A projectile is shot directly away from Earth's surface. Neglect the rotation of Earth. (a) As a multiple of Earth's radius RE, what is the radial distance a projectile reaches if its initial speed is one-fifth of the escape speed from Earth? ____ times RE

    asked by Jessy on January 15, 2007
  85. Economics

    Suppose that the residents of Vegopia spend all of their income on cauliflower, broccoli, and carrots. In 2006 they buy 100 heads of cauliflower for $200, 50 bunches of broccoli for $75, and 500 carrots for $50. In 2007, they buy 75 heads of cauliflower

    asked by Sarah on April 2, 2007
  86. math

    This is a statistics problem. A laboratory test for the detection of a certain disease give a positive result 5 percent of the time for people who do not have the disease. The test gives a negative result 0.3 percent of the time for people who have the

    asked by Anonymous on September 23, 2007
  87. physics

    If a gasoline engine has an efficiency of 21 percent and loses 780 J to the cooling system and exhaust during each cycle, how much work is done by the engine? Is it 3709.5??? Chemical energy in (as fuel and oxygen) = Work out + Heat out 21% is the ratio of

    asked by anonymous on February 15, 2007
  88. COLLEGE PHYSICS

    a uniform bridge span weighs 50x10^3 and is 40m long. A car weighing 15X10^3 is parked with its center of gravity located 12m from the right pier. what upward support force does the left pier provide? im lost....this is what i think im supposed to do

    asked by natali on November 11, 2007
  89. Physics

    A 1.0-kg ball on the end of a string is whirled at a constant speed of 2.0 m/s in a horizontal circle of radius 1.5 m. What is the work done by the centripetal force during one revolution? I did: F=m(v^2)/r F=1(2^2)/1.5=2.7 J The answer that was provided

    asked by Marisol on October 23, 2007
  90. Chemistry

    Commercial vinegar was titrated with NaOH solution to determine the content of acetic acid, HC2H3O2. For 20.0 milliliters of the vinegar 26.7 milliliters of 0.600-molar NaOH solution was required. What was the concentration of acetic acid in the vinegar if

    asked by Sarah on May 23, 2007
  91. related rates with work shown

    this is a relate rates problem in calculus in a right triangle, the hypotenuse is 5 and the vertical side is x and the angle is theta. so if theta increases at a constant rate of 3 radians per minute, at what rate is x increasing in units per minute when x

    asked by Anonymous on April 15, 2007
  92. chemistry

    Can someone please tell me why I would (or wouldn't) expect a color change if FeCl3 were added to pure aspirin and also to oil of wintergreen? (I know aspirin is mostly salicylic acid, and I'm not even sure what compounds are in oil of wintergreen, I'm

    asked by Lacey on June 12, 2007
  93. calculus

    The radius of a circle is increasing at a nonzero rate, and at a certain instant, the rate of increase in the area of the circle is numerically equal to the increase in its circumstance. At this instant, the radius of the cirle is... Here is what I did:

    asked by Anonymous on November 18, 2007
  94. physics

    while driving his sports car at 20.0 m/s down a four-lane highway, eddie comes up behind a slow-moving dump truck and decides to pass it in the left lane. If eddie can accelerate at 5.00 m/s2) (squared) how long will it take for him to reach a speed of

    asked by confusedd! on September 10, 2007
  95. Chemistry

    We performed a lab in class about a month ago concerning different types of equilibrium. One particular portion of the lab adding 5 mL of .3M HCl to 5 mL of .3 M Pb(NO3)2. After a precipitate finally formed, 8 mL of water was added to dissolve PbCl2. One

    asked by Kim on May 28, 2007
  96. help me for this stupid worksheet

    the question is.. why did the ghost decide to haunt city hall? urgh i don't fee like doing it so im hoping someone has the answer :] You might have gotten an answer if you'd told us the source of your question. To which story, poem, play are you referring?

    asked by brooke on January 31, 2007
  97. Chemistry

    I'm trying to find if potassium nitrate is polar or non-polar by using the electronegativity scale. Can someone check my work? Electronegativity: potassium: 0.82 nitrogen: 3.04 oxygen: 3.44 =3.44-3.04 =0.82-0.4 =0.4 =0.42 So the final answer is 0.42 and by

    asked by Marty on November 10, 2007
  98. balanced equation

    ? MnO4– + ?H+ + ?C2O42– --> ?Mn2+ + ?H2O + ?CO2 what's the balanced equation? correct coefficients? is it 1MnO4- + 2H+ + 1C2O42- --> 1Mn2+ + 1H20 + 2CO2 ? c2042..? are you missing parenthesis somewhere? oh i see, no i believe this is correct: MnO4- +

    asked by christine on April 29, 2007
  99. chemistry

    How many moles of solid Ba(NO3)2 should be added to 300 ml of .2 M Fe(NO3)3 to increase the concentration of NO3- ion to 1 M?

    asked by corey on October 3, 2007
  100. calculus

    a particle moves along the curve xy=10. if x=2 and dy/dt=3, what is the value of dx/dt. i'm guessing this is something to do with parametric equations. if x is 2, then y=5. but how do i get dx/dt. you have to differentiate the equation with respect to t so

    asked by Anonymous on April 21, 2007