Most popular questions and responses by kristen
  1. Chemistry

    Predict whether the following reactions will be exothermic or endothermic A) N2(g)+ 3H2(g) --> 2NH3(g) B) S(g) +O2(g) ---> SO2(g) C) 2H2O(g) ---->2H2(g) + O2(g) D) 2F(g) +F2(g) Bond H-H 432 kj/mol N-N(triple bond) 942 kj/mol O=O 494 KJ/Mol F-F 155 KJ/mol

    asked on January 22, 2012
  2. physics

    a 62.0kg bungee jumper jumps from a bridge. she is tied to a bungee cord whose unstretched length is 12.0 m and falls a total of 31m a) calculate the spring constant k of the bungee cord and b) calculate the maximum acceleration she experiences.

    asked on August 10, 2014
  3. physics

    a force of 20N compresses a spring with a spring constant of 50N/m. how much energy is stored in the spring?

    asked on July 23, 2014
  4. math

    Find the periodic payment R required to amortize a loan of P dollars over t yr with interest charged at the rate of r%/year compounded m times a year. (Round your answer to the nearest cent.) P = 100,000, r = 9.5, t = 23, m = 12

    asked on May 9, 2012
  5. Chemistry

    I don't know how to do Titration problems! I have an emergency homework assignment that's crucial to my grade! Please help with tips and step by step response! Please help!- 1. 50ml of 0.3 M KOH are required to titrate 60 ml of H^2SO^4. What is the M of

    asked on May 11, 2015
  6. college chemistry

    If KHP sample #1 requires 27.30 mL of NaOH solution to reach an endpoint, what volume should be required for samples #2 and #3?

    asked on October 25, 2012
  7. physics! Need help badly

    A 4.65 kg object is released from rest while fully submerged in a liquid. The liquid displaced by the submerged object has a mass of 2.60 kg. How far and in what direction does the object move in 0.300 s, assuming that it moves freely and that the drag

    asked on April 18, 2012
  8. algebra

    You buy 10 gallons of ice cream for a party, how many cup sized containers can you fill with this?

    asked on September 30, 2015
  9. physics

    NASA launches a satellite into orbit at a height above the surface of the Earth equal to the Earth's mean radius. The mass of the satellite is 550 kg. (Assume the Earth's mass is 5.97 1024 kg and its radius is 6.38 106 m.) (a) How long does it take the

    asked on September 27, 2015
  10. Physics

    Friction provides the force needed for a car to travel around a flat, circular race track. What is the maximum speed at which a car can safely travel if the radius of the track is 80.0 m and the coefficient of friction is 0.38?

    asked on February 3, 2011
  11. Chemistry

    How many Moles of solute particles are present in 1 mL of aqueous 0.070 M (NH4)2CO3? ____ mol of Particles

    asked on November 14, 2012
  12. AP Physics

    A uniform spherical shell of mass M and radius R rotates about a vertical axiss on frictionless bearings. A massless cord passes around the equator of the shell, over a pulley of rotational inertia I and radius r, and is attached to a small object mass m.

    asked on January 27, 2008
  13. AP Chem

    Calculate the pH after 0.010 mol gaseous HCl is added to 250.0 mL of each of the following buffered solutions: a. .050 M NH3/.15 M NH4Cl b. .5 M NH3/ 1.5 M NH4Cl

    asked on April 3, 2013
  14. Chemistry

    Write the equation for the dissolution of NH4NO3 in water. If 5.95 mol of NH4NO3 are dissolved, how many total moles of ions are produced? Answer in units of mol

    asked on March 13, 2014
  15. science

    How many grams of NH3, are required to produce 5.23 g HF?

    asked on March 31, 2010
  16. math

    Suppose payments were made at the end of each month into an ordinary annuity earning interest at the rate of 8%/year compounded monthly. If the future value of the annuity after 14 yr is $70,000, what was the size of each payment? (Round your answer to the

    asked on May 9, 2012
  17. geometry

    A grain storage tank is in the shape of a cylinder covered by half a sphere. The height of the cylinder is 50 feet and its diameter is 80 feet. find the total surface area (including the base) and volume of the tank.

    asked on April 21, 2009
  18. Chemistry

    Given that ∆Hº(Br(g)) = 111.9 kJ/mol ∆Hº(C(g)) = 716.7 kJ/mol ∆Hº(CBr4(g)) = 29.4 kJ/mol calculate the average molar bond enthalpy of the carbon-bromine bond in a CBr4 molecule.

    asked on January 23, 2013
  19. Math HELP!!!

    I’m a Connexus Student and I need help on lesson 10: Prisms and Surface Area

    asked on February 3, 2019
  20. Chemistry

    find the pH of each of the following solutions of mixtures of acids: .125M in HBr and .130 M in HCHO2, .155M in HNO2 and 9.0*10^-2M in HNO3, 5.5×10−2 in acetic acid and 5.5×10−2 in hydrocyanic acid

    asked on August 2, 2010
  21. physics

    a cue stick strikes a stationary pool ball, exerting an average forece of 50 N over a time of 7 milliseconds. If the ball has mass .1kg, what speed does it have just after impact?

    asked on January 14, 2008
  22. Physics

    Whenever two Apollo astronauts were on the surface of the Moon, a third astronaut orbited the Moon. Assume the orbit to be circular and 160 km above the surface of the Moon, where the acceleration due to gravity is 1.42 m/s2. The radius of the Moon is 1.70

    asked on October 2, 2012
  23. Grd 12 U English

    I am the discussion director for my group. I have to grab 4 reallyyy good discussion questions for the book The Kite Runner. I already found one good question, I need the other 3. It has to be from chapter 1-3 PLEASE help me out, i'm so stuck, honestly I

    asked on July 8, 2013
  24. physics

    A basketball player standing near the basket to grap a rebound, jumps 62 cm vertically. How much total time does the player speen in the top 15 cm of the jump? How much total time does the player spend in the bottm 15 cm of this jump?

    asked on September 9, 2007
  25. AP Physics

    A record turntable is rotating at 33 and 1/3 rev/min. A watermelon seed is on the turntable 7.5 from the axis of rotation Calculate the acceleration of the seed assuming that it does not slip? Suppose that the turntable achieves its angular speed by

    asked on January 27, 2008

    Hydrogen gas and iodine gas react via the equation, H2 + I2 2HI, and K=76 at 600K. If 0.05 mole of HI is placed in a flask at 600K, what are the equilibrium concentrations of HI, I2, H2? I am very lost at where to even start with this problem

    asked on March 18, 2012

    A paratrooper fell 380m from an airplane without being able to open his chute but happened to land in snow, suffering only minor injuries. Assume that his speed at impact was 58 m/s(terminal speed), that his mass (including gear) was 90 kg, and that the

    asked on January 12, 2008
  28. apush

    how did each of the following encourage social reform: second great awakening, industrialization, nostalgia for the past?

    asked on November 29, 2011
  29. algebra

    A worker is exposed to 98 dB for five hours and 82 dB for a three hours, giving an eight hour working day. On average what noise level is this worker exposed to? (round to the nearest whole number)

    asked on September 21, 2015
  30. chemistry

    When magnesium is heated in air, it reacts with oxygen to form magnesium oxide. 2Mg + O2 --> 2MgO If the mass of the magnesium increases by 0.335 g, how many grams of magnesium reacted? A. 0.882 B. 0.441 C. 0.509 D. 1.02 E. Not enough Info

    asked on July 5, 2010
  31. Science

    PLEASE CHECK MY ANSWERS!! I AM SOO FAR BEHIND IN THIS CLASS! 1. Which of the following describes the effect of high altitude on climate? Rain is very rare Flooding is more likely Temperatures are lower

    asked on November 21, 2018
  32. precalc

    Eliminate the parameter and write the corresponding rectangular equation. X=2cos theta, y=4sin theta

    asked on February 24, 2008
  33. PreCalc

    The half-life of krypton-91 (91Kr) is 10 s. At time t = 0 a heavy canister contains 5 g of this radioactive gas. (a) Find a function m(t) = m02−t/h that models the amount of 91Kr remaining in the canister after t seconds.

    asked on December 4, 2016
  34. Physics

    "Rocket Man" has a propulsion unit strapped to his back. He starts from rest on the ground, fires the unit, and accelerates straight upward. At a height of 16 m, his speed is 5.0 m/s. His mass, including the propulsion unit, has the approximately constant

    asked on October 21, 2015
  35. Chemistry

    The half-life for the first-order conversion of A to B is 56.5 hours. How long does it take for the concentration of A to decrease to 10.0% of its original amount? Our professor has given us the answer - 188hr but I am not entirely sure how he got it.

    asked on February 23, 2014
  36. math

    the bag contains 20 red marbles and30 white marbles and 40 blue ones what is the ratioof red to blue marbles what is the ratio of white to red if one marble is drawn from the bag what is the probability that the marble will not be white??? need ansewr

    asked on April 8, 2012
  37. physics

    a long jumper takes off at an angle of 20 degrees with the horizontal and reaches a maximum height of 0.55 meters at mid- flight. how far did she jump?

    asked on June 27, 2014
  38. College Chemistry

    A heat lamp produces 22.5 watts of power at a wavelength of 6.0 Mu.How many photons are emitted per second? (1watt= 1J/s )

    asked on February 4, 2012
  39. Physics Honors

    A car travels due east with a speed of 60.0 km/h. Rain is falling vertically with respect to the Earth. The traces of the rain on the side windows of the car make an angle of 45.0° with the vertical. Find the velocity of the rain with respect to the car

    asked on October 16, 2010
  40. math

    the maximun height of a ferris wheel is 35m. the wheel takes 2 mins to make one revolution. passengers board the ferris wheel 2m above the ground at the bottom of the rotation. a. write an equation to model this b. how high is the passengers after 45s c.

    asked on July 25, 2011
  41. physics

    A 78 cm long, 0.8 mm diameter steel guitar string must be tightened to a tension of 1600 N by turning the tuning screws. By how much is the string stretched?

    asked on March 14, 2012
  42. Science

    In order for hurricane or tropical storm to develop the temperature of the ocean must be A) 20 degrees F B) 40 degrees F C) 60 degrees F D) 80 degrees F

    asked on January 31, 2019
  43. physics

    a force F is applied in horizontal to a 10kg block. the block moves at a constant speed 2m/s across a horizontal surface. the coefficient of kinetic friction between the block and the surface is 0.5. the work done by the force F in 1.5 minutes is?

    asked on July 23, 2014
  44. Physics

    A ball weighing 50N is pulled back by a rope to an angle of 20 degrees (the rope that the ball hangs from). Find the tension in the pulling rope.

    asked on October 7, 2012
  45. geometry

    The limestone blocks from which an ancient pyramid was made weigh about 2 tons per cubic yard. Find the approximate weight of the pyramid having a square base of length 250 yards and a height of 150 yards.

    asked on April 21, 2009
  46. AP physics

    A uniform spherical shell of mass M and radius R rotates about a vertical axiss on frictionless bearings. A massless cord passes around the equator of the shell, over a pulley of rotational inertia I and radius r, and is attached to a small object mass m.

    asked on January 27, 2008
  47. Medical Term

    I need some help with medical terms. I need to determine the word parts and the definition and I'm having a hard time with these 2. stomatoesophagogastroenterocolitis cardiosphygmopneumographologist

    asked on September 16, 2015
  48. Math

    A box can hold 175 cubic inches of cereal. Of the box is 7 inches long and 2.5 inches wide, how talk is it ?

    asked on April 26, 2016
  49. Math

    An airplane is flying at an airspeed of 500 km/hr in a wind blowing at 50 km/hr toward the southeast. In what direction should the plane head to end up going due east? (Round your answer to two decimal places.)What is the airplane's speed relative to the

    asked on August 28, 2015
  50. physics

    a 62.0kg bungee jumper jumps from a bridge. she is tied to a bungee cord whose unstretched length is 12.0 m and falls a total of 31m a) calculate the spring constant k of the bungee cord and b) calculate the maximum acceleration she experiences.

    asked on August 9, 2014
  51. Math

    A commercial refrigerator unit accidentally releases 12.5 L of ammonia gas at SATP. Determine the mass and number of molecules of ammonia gas released. Please if possible show the steps because I have an exam in an hour and I was trying this question and

    asked on June 21, 2013
  52. Algebra 2

    The loudness L of sound in decibels is given by L= 10log (l/lo) where l is the intensity of sound and lo is the intensity of the least audible sound. If lo= 10^-12 w/m^2, about how many times more intense is a 108 decibel sound than a 100 decibel sound?

    asked on February 27, 2019
  53. math

    find the sum of the measures of the intieior angles of each polygon. -hexagon -pentagon -quadrilateral -octagon -16-gon -27-gon The key is the sum of the measures. All of these figures have the same total number of degrees in their interior angles. What do

    asked on March 12, 2007
  54. Physics

    A traffic light hangs from a pole as shown. The uniform aluminum pole AB is 7.70m long and has a mass of 11.0kg. The mass of the traffic light is 27.5m. 1. Determine the tension in the horizontal massless cable CD. 2. Determine the vertical and horizontal

    asked on November 2, 2012
  55. Math

    What is the smallest counting number n so that 375n is a perfect square?

    asked on January 22, 2014
  56. math

    one sixth of five dozen computers were shiped how many were not shiped b what was the ratio of computers were shipped to those that were not shipped c what percent of computers were shiped

    asked on March 26, 2012
  57. Duration

    Find the duration of a 6% coupon bond making annual coupon payments if it has three years until maturity and a yield to maturity of 6.5%. What is the duration if the yield to maturity is 10.5%?

    asked on April 10, 2014
  58. trig

    establish the identity: cot(A-B)= cotAcotB+1/cotB-cotA thanks for any help at all

    asked on July 16, 2008
  59. AP Physics

    An airplane in a horizontal circle at a speed of 130.5556 m/s. If its wings are tilted 40 degress to the horizontal, what is the radius of the circle in which the plane is flying? Assume that the required force is provided entirely by an "aerodynamic lift"

    asked on October 28, 2007
  60. algebra

    An “A” is considered 4.0, a “B” is 3.0, a “C” is 2.0, a “D” is 1.0, and an “F” is 0. In your first semester you received the following grades. Calculate your grade point average English = credits 3.0 Grade = C Biology = credits 4.0

    asked on September 22, 2015
  61. algebra

    Julie the Jeweler has fifteen gold necklaces worth $120 each, nine silver necklaces valued at $90 each, ten plated necklaces valued at $60 each and thirty beaded necklaces worth $15 each. What is the average value of a necklace at Julie’s shop? (round to

    asked on September 22, 2015
  62. Chemistry

    Describe, in detail, how to make 5.5 liters of a 2.5 molar HCl solution from a 10.5 molar HCl stock solution.

    asked on February 22, 2011
  63. Chemistry

    If 20ml of glacial acetic acid (pure HC2H3O2) is diluted to 1.5L with water, what is the pH of the resulting solution. The density of glacial acetic acid is 1.08g/ml

    asked on August 2, 2010
  64. Physics

    A student drops a stone from the edge of a sea cliff. The sound of the stone striking the ocean is heard 3.8s after the stone is released. The speed of sound in air is 340m/s. Find the height of the cliff. Ignore air resistance.

    asked on November 1, 2018
  65. Tech Business

    PLEASE HELP!! I'm so behind. Are my answers correct? This is my last class to pass to graduate, and I have a hard time with it. 1. Which of the following Web 2.0 tool can aid in searches using key words? A) Blogging B) Podcasting C) Tagging(My answer) D)

    asked on September 19, 2018
  66. science

    If a temperature increase from 19.0 degrees C to 36.0 degrees C triples the rate constant for a reaction, what is the value of the activation barrier for the reaction?

    asked on March 13, 2011
  67. algebra

    On a quiz worth 5 points, four students earned a 5, seven students earned a 4, six students earned a 3, two students earned a 2, and one student earned a zero. Find the average score. (round to one decimal place)

    asked on September 21, 2015
  68. chemistry

    how many moles of NH3 does it take to make 8.0 mol of H20 according to the reaction shown below? 4NH3 + 5O2 --> 4NO + 6H2O I REALLY NEED HELP WITH THIS AS I AM LOST. PLEASE PROVIDE NOTES.

    asked on September 13, 2016
  69. Chemistry

    Suppose that you are planning a backpacking trip and will need to boil 40 L of water for your group. What volume of fuel should you bring? Assume each of the following: the fuel has an average formula of C7H16; 15% of the heat generated from combustion

    asked on October 31, 2010
  70. chemistry

    2. Methanol, CH3OH, is used as fuel in race cars. This liquid fuel can be synthesized using the following process C(s)+ ½ O2(g) + 2H2(g)  CH3OH(l) Calculate delta G using the deta Gf of the reaction. Calculate Kp. What is the relation between the

    asked on April 15, 2010

    A .35 kg ladle sliding on a horizontal frictionless surface is attached to one end of a horizontal spring (with the spring constant (k) =455 N/m) whose other end is fixed. The mass has a kinetic energy of 10 J as it passes through its equilibrium position

    asked on November 18, 2007
  72. physics

    A 3.00-liter aluminum cylinder at 5.00°C is filled to the brim with gasoline at the same temperature. If the aluminum and gasoline are warmed to 52.0°C, how much gasoline spills out? [Hint: Be sure to account for the expansion of the container. Also,

    asked on June 13, 2011
  73. Physics

    A 1440-kg crate of cabbages is laid on a level, frictionless track at the end of a heavy spring. The spring is compressed a distance of 0.100 m by a force of 83500 N. When the spring is released, it propels the crate. the spring constant of the spring

    asked on April 4, 2011
  74. Calculus

    Find two positive numbers that satisfy the requirements: "The product is 147 and the sum of the first number plus three times the second number is a minimum."

    asked on November 4, 2013
  75. communication

    Please HELP!! Question 1 of 20 5.0 Points Which of the following would be the LEAST appropriate in the closing paragraph of a negative message? A. "Let us know if model #A01 would be a suitable substitution." B. "Our layaway plan will enable you to

    asked on February 4, 2013
  76. chemistry

    A compressed gas cylinder contains 1.00 103 g of argon gas. The pressure inside the cylinder is 2035 psi (pounds per square inch) at a temperature of 15°C. How much gas remains in the cylinder if the pressure is decreased to 610. psi at a temperature of

    asked on April 14, 2010
  77. Chemistry

    Calculate the wavelength of light if 1.50 mol of photons has an energy of 125 kJ. 6.02x10^23 things=1.00 mol(things) c=3.00x10^8 m/sec h=6.626x10^-34 J sec

    asked on February 28, 2013
  78. Physics

    We consider the case shown in the figure below. Two objects with masses m and M are connected with a taut string running over a pulley. The pulley rotates without friction. The two masses are given as M = 6.23 kg and m = 2.54 kg. A second taunt string

    asked on October 4, 2011
  79. AP physics

    do you guys have an someone that good with advanced physics, because i have a few problems that i am not sure how to do and its for my AP physics class, and I wasn't sure if you had someone on board now that could help thanks

    asked on January 27, 2008
  80. AP lost

    An elevator and its load have a combined mass of 1550 kg. Find the tension in the supporting cable in Newtons when the elevator , originally moving downward at 11 m/s, is brought to rest with constant acceleration in a distance of 43 m.

    asked on October 15, 2007
  81. Finance

    A bond currently sells for $1,120, which gives it a yield to maturity of 5%. Suppose that if the yield increases by 25 basis points, the price of the bond falls to $1,070. What is the duration of this bond?

    asked on April 10, 2014
  82. Math

    Four hoses are filling a pool. The first hose alone would fill the pool in 4 hours while the second hose takes 6 hours. The third hose and the fourth hose each take 8 hours to fill the pool. How long would it take to fill the pool if all 4hoses are turned

    asked on November 20, 2013
  83. Chemistry

    35 grams of sodium phosphate are mixed with enough water to make 3.5L of solution having a densityof 1.045g/mol. Find the concentration of sodium phosphate in ppm. Using the same information, find the molarity of the sodium and phosphate ions.

    asked on February 15, 2012
  84. Physics

    Please help I've attempted this problem various ways and I can't seem to get the correct answer. A 69.0 kg person throws a 0.0410 kg snowball forward with a ground speed of 35.0 m/s. A second person, with a mass of 60.0 kg, catches the snowball. Both

    asked on June 3, 2011
  85. Physics

    A load of 54 N attached to a spring hanging vertically stretches the spring 4.9 cm. The spring is now placed horizontally on a table and stretched 14 cm. What force is required to stretch it by this amount?

    asked on November 23, 2010
  86. human anatomy and physiology

    3. Critical to life is the function of the cell membrane and its ability to move materials across the cell membrane. Define each of the following in detail using diagrams to aid the understanding of the process. a) diffusion b) osmosis c) facilitated

    asked on August 23, 2005
  87. Pre calculus

    Tanx + sinxsecx/ cscxtanx

    asked on February 10, 2013
  88. physics

    A diver, below the surface of a lake, notices that no light appears to be coming toward her greater than the angle è, measured from the vertical. If the index of refraction of water is 1.33, what is the angle è (which is the critical angle of total

    asked on November 28, 2011
  89. Physics

    A 1440-kg crate of cabbages is laid on a level, frictionless track at the end of a heavy spring. The spring is compressed a distance of 0.100 m by a force of 83500 N. When the spring is released, it propels the crate. the spring constant of the spring

    asked on April 11, 2011

    Which of the following statements about NAD+ is false? A). NAD+ is reduced to NADH during both glycolysis and Krebs cycle B). NAD+ had more chemical energy then NADH C). NAD+is reduced by the action of dehydrogenases D). NAD+ can receive electrons for use

    asked on November 4, 2007
  91. Chem 116

    How do I calculate 25.00mL of 5.0*10^-4 M of FeSCN^2+ using 0.002 M Fe(NO3)3, 0.002 M KSCN, 0.1 M of HNO3 and water?

    asked on February 25, 2010
  92. ap phyiscs

    A bowler throws a bowling ball of radius R=11 cm down a lane. The ball slides on the lane, with initial speed v(of the center of mass)=7 m/s and initial angular speed =0. The coefficient of kinetic friction between the ball and the lane is .25. The

    asked on February 10, 2008
  93. I really dont get this. physics

    A .35 kg ladle sliding on a horizontal frictionless surface is attached to one end of a horizontal spring (with the spring constant (k) =455 N/m) whose other end is fixed. The mass has a kinetic energy of 10 J as it passes through its equilibrium position

    asked on November 18, 2007
  94. AP Physics...ahaha

    A drowsy cat spots a flowerpot that sails first up and then down past an open window. The pot was in view for a total of .43 s, and the top-to-bottom height of the window is 2 m. How high aboe the window top did the flowerpot go?

    asked on September 9, 2007
  95. physics

    a man stands on the roof of a 15.0m tall building and throws a rock with a velocity of magnitude 30.0m/s at an angle of 33 degrees above the horizontal. ignoring resistance calculate the horizontal distance from the base of the building to the point where

    asked on June 27, 2014
  96. Physics

    A constant force of 35.9 N, directed at 28.7o from horizontal, pulls a mass of 14.7 kg horizontally a distance of 3.41 m. Calculate the work done by the force.

    asked on October 20, 2013
  97. English (Ms.Sue please answer) I did some work own

    Ok so Im thinking I will use the theme of heroism (which is the human condition) My arguments would be character, social position and ancestry This is a book and movie comparative essay... I have to do a comparative essay on a book and a film (I chose The

    asked on July 21, 2013
  98. physics

    As a train moves away from you, the frequency of its whistle is determined to be 475Hz. If the actual frequency was 500 Hz and the speed of sound in air is 350m/s, what is the Train's speed? answer is 18.4m/s please show and explain steps

    asked on July 17, 2013
  99. math

    If a picture is 4 inches tall and 9 in. wide is to be scaled to 2.5 in. tall how wide should the be for the two pictures to be similar?

    asked on January 9, 2013
  100. Chemistry

    A solution is made by dissolving 18.9 g of HCl in enough water to make 716 mL of solution. Calculate the pH of the solution at 25 degrees C

    asked on December 5, 2012


  1. 1
  2. 2
  3. 3
  4. 4