Most popular questions and responses by kristin
  1. Chemistry

    write the balanced equation for the ionization of the weak base pyridine, C5H5N, in water

    asked on May 8, 2011
  2. Math

    The top of a tree makes angles s and t with Points K and L on the ground, respectively, such that the angles are complementary. Point K is x meters and Point L is y meters from the base of the tree. A)In terms of x and y, find the height of the tree.

    asked on September 10, 2015
  3. Help me solve??

    XYZ has vertices X(5,6), Y(9,12), and Z(12,8). it is translated right 8 units and up 3 units. What are the coordinates of X', Y', and Z' ?

    asked on April 25, 2014
  4. calculus

    The function f is continuous on the closed interval [0,6] and has values that are given in the table below. x |0|2|4|6 f(x)|4|K|8|12 The trapezoidal approximation for(the integral): 6 S f(x) dx 1 found with 3 subintervals of equal length is 52. What is the

    asked on May 2, 2011
  5. Physics

    A coiled Hookean spring is stretched 10 cm when a 1.5kg mass is hung from it. Suppose a 4 kg mass hangs from the spring and is set into vibration with an amplitude of 12 cm. A. Find the force constant of the spring. B. Find the Maximum restoring force

    asked on February 16, 2011
  6. Survey Math help

    A movie complex has eight different movie theaters. The manager of the complex wants to conduct a survey to determine which snacks to add to the menu. Which represents the best sample the manager could use for the survey? Would I do specific ages the first

    asked on May 1, 2014
  7. Math word problem

    Patsy has cheerleading practice on every fourth school day. She wants to be in the school play, but they have practice on every sixth school day. If both started on September 5th, what would be the first date that she has to choose between cheerleading and

    asked on December 5, 2012
  8. Chemistry

    The standard enthalpies of formation of ions in aqueous solutions are obtained by arbitrarily assigning a value of zero to H ions;that is, delta H(f) [H+(aq)]=0 A.for this reaction: calculate delta H(f) for the Cl- ions. HCl(g) ==H2O==>H+(aq)+Cl-(aq) delta

    asked on October 31, 2010
  9. Analytical Chemistry

    A 10.0 mL sample of whiskey was diluted to 500.0 mL. A 4.00 mL aliquot of the diluted sample was removed and the ethanol, C2H5OH, was distilled into 50.00 mL of 0.02150 M K2Cr2O7 and oxidized to acetic acid. The excess Cr2O72– was then back titrated with

    asked on October 18, 2015
  10. Chemistry

    I'm trying to find the solubility of Ca(OH)2 in .0125 mol/L aqueous NaOH. Here is my data: Vol of solution used per titration: 20mL Conc of HCl: .1201 mol/L Average Titre: 4.71 I need to calculte: 1. the TOTAL [OH-] in the saturated solution of Ca(OH)2 in

    asked on April 14, 2010
  11. math

    five students make the following guesses on the number of jelly beans in a jar: 72, 78, 68, 60 and 84. the guesses were off by 14, 2, 4, 6 and 10 (not in order). how many jelly beans are in the jar?

    asked on January 26, 2011
  12. calculus

    Meg's pension plan is an annuity with a guaranteed return of 4% per year (compounded quarterly). She would like to retire with a pension of $20,000 per quarter for 10 years. If she works 30 years before retiring, how much money must she and her employer

    asked on September 16, 2013

    Two 75 kg hockey players skating at 5.50 m per s collide and stick together. if the angle between their initial directions was 120 degress, what is their velocity after the collision?

    asked on November 5, 2013
  14. Chemistry

    What is the standard cell potential of a cell made of theoretical metals Ms/Ma^+2 and Mb/Mb^+2 if the reduction potentials are -0.19V and -0.85 V, respectively? +0.66V -0.66V +1.04 V*** -1.04V

    asked on June 1, 2016
  15. Physics

    If a projectile is launched from Earth with a speed equal to the escape speed, how high above the Earth's surface is it when its speed is three-fifths the escape speed? I keep getting the answer 2.56x10^6 m after solving it a few different ways. Help would

    asked on April 28, 2012
  16. Physics

    A 3.30-kN piano is lifted by three workers at a constant speed to an apartment 28.8 m above the street using a pulley system fastened to the roof of the building. Each worker is able to deliver 197 W of power, and the pulley system is 75.0% efficient (so

    asked on June 17, 2012
  17. Chemistry

    What symbol is used to show the standard reduction potential of an oxidation reaction in a half cell? The sub means what follows is a subscript So the 0 is a superscript and the sub is its subscript E^0 sub cell*** E^0 sub red E^0 sub oxid All of the above

    asked on June 1, 2016
  18. Math help!

    Jack has the following scores on exams in his math class. 81, 87, 93, 89, 61, 81 If he wants to make his performance sound as good as possible, which measure should he use—the mean, the median, or the mode of his exam grades when he talks about how he is

    asked on October 10, 2012
  19. physic

    A 0.20 kg ice cube at 0.0° C has sufficient heat added to it to cause total melting, and the resulting water is heated to70deg.Cel. > How much heat is added? (For water Lf=334kj/kg > andLv=2257kj/kg >

    asked on July 24, 2010
  20. Chemistry

    The ethylammonium ion, CH3CH2NH3+, has a pKa of 10.81. It reacts with water to form ethylamine, CH3CH2NH2 and H3O+. Which of the following statements is true at pH 7? A.) ethylamine predominates B.) ethylammonium ion predominates C.) the pH is higher than

    asked on April 6, 2015
  21. math

    I just saw this guy post this here and I think he needs help??? A recipe calls for 4 pounds of have 60 ounces of fruit. you have as much fruit as you need? B.if not,how much more do you need?

    asked on January 8, 2014
  22. what??

    im not trying to fool anything this is not a name change.MS.SUE Im not trying to be disrecptful since you do help a lot of kids but I also have talking to a lot of kids to and they say that sometimes your very rude and just trying the help the

    asked on January 8, 2014
  23. math

    An urn holds 13 identical balls except that 2 are white, 4 are black, and 7 are red. An experiment consists of selecting two balls in succession without replacement and observing the color of each of the balls. How many outcomes are in the sample space for

    asked on February 2, 2011
  24. literature

    What are the parts of speech to each word in this sentence: I like the movie Clueless its based on Jane Austens novel Emma.

    asked on September 7, 2009
  25. math

    In a lottery game, a player picks 9 numbers from 1 to 43. How many different choices does the player have if order doesn't matter?

    asked on November 19, 2016
  26. trig

    find the coordinates of the terminal point on the unit circle determined by t=9pt/7 to two decimal places

    asked on November 13, 2011
  27. calculus

    compute the average velocity of a stone over time intervals 1, 1.01 1, 1.001 1, 1.0001 and .99,1 .999,1 .9999,1. use this to estimate instantaneous velocity at t=1 All i can figure out the formula should be s(t1)-s(t0) over t1-t0 how does that give you a

    asked on August 25, 2009
  28. math

    An urn holds 13 identical balls except that 2 are white, 4 are black, and 7 are red. An experiment consists of selecting two balls in succession without replacement and observing the color of each of the balls.

    asked on February 2, 2011
  29. Chem

    Caculate the volume of CO2 gas given off at 756 mm Hg and 23C when 150 kg of limestone(CaCO3) is heated until it decomposes according to the following reaction:CaCO3(s)=CaO(s)+CO2(g)

    asked on March 13, 2013
  30. Chemistry

    How many moles of chlorine are there in 16.0 mL of 0.450 M CaCl2? 0.0072 mol 0.0144 mol 0.0216 mol 0.0375 mol none of the above I had chose 0.0072 and had submitted it in my assignment, but it had said it was wrong. I chose 0.0072 because I did this

    asked on April 20, 2015
  31. Chemistry

    The Ka for the reaction of acetic acid and water is 1.8 x 10-5. Which of the following statements is true at pH 7? A.) there is much more acetic acid than acetate ion B.) there is more acetate ion than acetic acid C.) the concentration of acetate ion is

    asked on April 6, 2015
  32. Calculus

    A fragment of bone is discovered to contain 20% of the usual carbon-14 concentration. Estimate the age of the bone to the nearest hundred years, given that Carbon-1 is radioactive with half-life of 5730 years and the rate of decay is given by the following

    asked on May 21, 2014
  33. Chemistry

    What mass of copper(II) nitrate would be produced from the complete reaction of 65.3 g of copper, according to the chemical reaction shown below? Cu + 2 AgNO3 ----> Cu(NO3)2 + 2 Ag Use the masses to two decimal places using the periodic chart in the front

    asked on October 18, 2013
  34. Chemistry

    If solution A had a pH of 8, and solution B had 1,000 times this hydrogen ion concentration what would be the pH of solution B, and would solution B be acidic or basic?

    asked on November 14, 2011
  35. Chem 100

    at 1 atm how much energy is required to heat 67 grams of H2O(s) at -22 degrees C to H2O(g) at 159 degrees C

    asked on May 1, 2011
  36. Physics

    You attach one end of a spring with a force constant k = 893 N/m to a wall and the other end to a mass m = 2.02 kg and set the mass-spring system into oscillation on a horizontal frictionless surface as shown in the figure. To put the system into

    asked on April 22, 2015
  37. math

    please explain how to get the answer to this question. five students make the following guesses on the number of jelly beans in a jar: 72, 78, 68, 60 and 84. the guesses were off by 14, 2, 4, 6 and 10 (not in order). how many jelly beans are in the jar?

    asked on January 27, 2011
  38. physics

    A tennis ball is dropped from the top of a building. It falls for 2.5 seconds before it hits the ground. (a) What velocity is the tennis ball traveling right before it hits the ground? (b) How high is the building?

    asked on January 21, 2010
  39. math

    find the missing length of the right triangle one side is 20 and th other side is 48?? help

    asked on October 3, 2009
  40. Chemistry

    Anhydrous aluminum oxide can be reduced to aluminum according to thisa chemical equation: 2 Al2O3 (s) ---> 4 Al (l) + 3 O2 (g) Calculate the mass of aluminum oxide reacted if 82 g of Al was produced and the percent yield was found to be 89.3%

    asked on October 18, 2013
  41. Physics

    The position vector r of a particle moving in an xy plane is given by [r = (6t^3-3t)i + (4-1t^4)j] with r in meters and t in seconds. What is the angle between the positive direction of the x axis and a line tangent to the particle's path at t = 3 s? Give

    asked on September 25, 2011
  42. chemistry

    When 0.100 mol of carbon is burned in a close vessel with 8.00g of oxygen, how many grams of carbon dioxide can form?

    asked on July 24, 2011
  43. Chemistry

    The solubility of compounds containing the carboxylic acid group can be increased by reaction with a) sulfuric acid b) nitric acid c) sodium hydroxide d) water e) benzoic acid Would it be sodium hydroxide since it is a base?

    asked on March 21, 2010
  44. Science.

    What did scientist learn from studying Supernova 1987A?

    asked on January 6, 2009
  45. Chemistry

    Four sets of conjugate acid/base pairs and Ka of the acid are given. Which pair would be the best to form a buffer at pH = 9.2? You can use the Henderson-Hasselbalch equation to answer this question. HCNO/CNO- 3.5 x 10-4 HC2O4-/C2O4- 5.1 x 10-5 H2CO3/HCO3-

    asked on April 20, 2015
  46. physics

    A 0.205 kg bird flying along at 7.8 m/s sees a 0.029 kg insect heading straight toward it with a speed of 15 m/s (as measured by an observer on the ground, not by the bird). The bird opens its mouth wide and enjoys a nice lunch. What is the bird's speed

    asked on March 30, 2015
  47. Math

    If you put me into 7 equal groups with 3 in each group and 5 are left over, what number am I?

    asked on March 6, 2014
  48. science

    Which of the following is true about an object that floats in water? (1 point) The object is less dense than frozen water. The mass of the object is less than that of water. The density of the object is less than that of water. The volume of the water is

    asked on March 1, 2013
  49. Physics

    A driver in a car traveling at a speed of 56.0 mi/h sees a deer 116 m away on the road. Calculate the minimum constant acceleration that is necessary for the car to stop without hitting the deer (assuming that the deer does not move in the meantime).

    asked on February 2, 2012
  50. AP Chemistry

    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 on December 4, 2011
  51. 3rd math

    Bethany has 40 apples. Write a subtraction story about the apples that would require regrouping. Then write the answer in a complete sentence.

    asked on September 19, 2011
  52. physics/math

    Joe is a former basketball player who is now a work-out junkie, and especially loves to do push-ups. He was a good athlete, but not so good at science in school, especally not good in Physics. He wants you, yes you, to calculate how much work he does, in

    asked on August 12, 2008
  53. Physics

    A rocket with a mass M moves along an x axis at the constant speed vi=40 m/s. A small explosion separates the rocket into a rear section (of mass m1) and a front section; both sections move along the x axis. The relative speed between the rear and front

    asked on April 10, 2008
  54. Physics

    What is the difference in volume (due only to pressure changes, not temperature or other factors) between 1000 kg of water at the surface (assume 4 degrees C) of the ocean and the same mass at the deepest known depth, 8.00 km? (Mariand Trench; assume also

    asked on November 6, 2007
  55. West and Worlds since 1500

    Which of the following are ways that intellectual, political, social, and religious developments of the seventeenth century were related, especially in regard to the dynamics of the Scientific Revolution? Check all that apply. The English Revolution

    asked on January 31, 2018
  56. Geometery help"Steve"

    The point Q(x,y) is reflected in the origin. Use arrow notation to describe the original point and its reflection. I chose this: (x,y) to (x,y) Am I right?

    asked on April 25, 2014
  57. chemistry

    a. How many atoms of hydrogen are in 25.0 g of ammonia (NH3)? Use the format 6.02E+23 for 6.02 x 1023 b. How many atoms of nitrogen are in the same amount of ammonia? Use the molar mass to two decimal places found on the periodic table in the front of your

    asked on October 18, 2013
  58. english

    Please help me write an essay. the question is "What do you think the theme is of Our Town and how is it shown?"

    asked on January 6, 2013
  59. statistics

    The average temperature in households is 67.6 degrees F. The standard deviation is 4.2 degrees F. A random sample of 51 households is to be selected What is the probability that the average of this sample will be within 1.4 STANDARD ERRORS of the

    asked on September 28, 2012
  60. History

    How did england change after its war with spain? and How did this change played a role and part in history by analyzing the magnitude and scope?

    asked on September 23, 2012
  61. Chemistry

    If you reclaim 0.250g Ag from AgNO3, how much AgNO3 did you have to begin with?

    asked on July 16, 2012
  62. Physics help please

    suppose you have 2 cars, and the larger one is twice as massive as the smaller one. If you and a friend push on them so that their accelerations are equal, how must the forces applied to the cars compare? a. the force on the larger car is equal to that on

    asked on November 27, 2011
  63. 4th grade math

    Find a rule that gives the third number from the first two numbers. Fill in the blanks.....10, 4, 5, ? 15, 7,7, ? 19,9,?

    asked on March 17, 2011
  64. Chemistry

    I don't understand how you know what state designation things are in a chemical equation. For example this is given: 2 (NH4)3PO4 (__) + 3 Ba(NO3)2 ---> Ba3(PO4)2 (__) + 6 NH4NO3 (__) How do you just know what to put for their state or phase designation?

    asked on March 10, 2011
  65. Chemistry

    The solubility of compounds containing the carboxylic acid group can be increased by reaction with a) sulfuric acid b) nitric acid c) sodium hydroxide d) water e) benzoic acid

    asked on March 21, 2010
  66. math

    1) x+8y=33 -x+4y=3 I need help solving this one using the elimination method!

    asked on March 13, 2010
  67. math

    1) 6m+n=47 m-4n=12 can someone help me solve using substitution method?

    asked on March 13, 2010
  68. math

    can someone please help me with this elimination methods problem? 0.05x+0.25y=11 0.15x+0.05y=12 solve using the elimination method and give the ordered pair...

    asked on March 13, 2010
  69. Math

    Can someone help me solve the following problems using the substituion method? I need to find the ordered pairs and I do not get it.... Here they are 1) 6m+n=47 m-4n=12 2) 6x+4y=-10 -7x+y=57 3) 5x+7y=43 -4x+y=25

    asked on March 13, 2010
  70. physics

    If you see a lightening bolt, then count 4 seconds until you hear thunder, about how far away was the lightening strike?

    asked on January 21, 2010
  71. physics

    If an arrow is fired at 200km/h horizontally, about how long will it take to strike a target 30 meters away?

    asked on January 21, 2010
  72. 5th grade

    Rajen chose a secret number and gave these clues to his friends. the number is even and it is divisible by 3, three times the number is less than 60 but greater than 40. what is Rajen's number?

    asked on January 13, 2010
  73. math

    is the following set of numbers a perfect triple? 13,15,18

    asked on October 3, 2009
  74. Medical

    what might be the cause of onset of social fobia in a 19 year old boy?

    asked on October 1, 2009
  75. chem

    The total pressure in a flask containing air and ethanol at 257C is 878 mm Hg. The pressure of the air in the flask at 257C is 762 mm Hg. If the flask is immersed in a water bath at 300C, the total pressure is 980 mm Hg. The vapor pressure of ethanol at

    asked on April 26, 2009
  76. vocab, again! sorry!

    Hi, again. I need help with this word decorum. the def is ADJ proper; seemly correct how do i use this in a sentence?

    asked on October 6, 2008
  77. science

    mercury is what planet from the sun?

    asked on June 2, 2008
  78. Chemistry

    To charge a lead storage battery you must apply a direct current to it. hold a magnet close to it. force alternating current through it.*** increase the pressure on it.

    asked on June 1, 2016
  79. Physics

    A block of mass 8.60 kg is pulled along a horizontal frictionless surface by a cord that exerts a force of 33 N at an angle 29.40 degrees from the horizontal. What is the magnitude of the normal force exerted on the mass by the floor? I solved for the

    asked on October 7, 2015
  80. Calculus

    find the co-ordinates y=x(2-x) where the gradient is 2

    asked on May 21, 2014
  81. Calculus

    1/X by first principles

    asked on May 21, 2014
  82. Calculus

    Find the volume of the solid generated by rotating about the y axis the area in the first quadrant bounded by the following curve and lines. y=x^2, x=0, y=2.

    asked on May 21, 2014
  83. Physics

    The focal length of the objective of a telescope is 0.2 m and the eyepiece has a focal length of 1.6 m. What is the length of the telescope? A. 1.8 m B. 1.4 m C. 1.6 m D. .90 m E. 8.0 m

    asked on January 20, 2013
  84. science

    A conatiner filled with marbles weighs 435 grams. The container weighs 28 grams. What is the mass of the marbles?

    asked on September 18, 2012
  85. Economics

    Suppose that a tour bus business incurred implicit costs of $600,000 and explicit costs of $7 million in a specific year. If the firm sold 125,000 tours at $60 per person, its accounting: A) profits were $100,000 and its economic profits were $500,000. B)

    asked on September 13, 2012
  86. business stat

    1. Suppose quality control inspectors at the coffee house chain take a sample of 100 pieces of this chocolate product from an incoming shipment. They find a sample average of 60% cacao with a standard deviation of 8%. What is the standard error of the

    asked on July 23, 2012
  87. geometry

    Factor 15x^2 - 8x - 16

    asked on March 8, 2012
  88. chemistry

    design a simple lever that could be raised and lowered smoothly using niitinol wires.

    asked on February 16, 2012
  89. physics

    a rocket blasts off and moves up with an acceleration of 12 m/s2 until it reaches 30 m then the engine shuts down and the rocket continues in free fall. What is the max hieght of the rocket and what is the total duration of the rockets flight?

    asked on August 31, 2011
  90. grammar

    A Superblade was used at the 2 o'clock position, and the anterior chamber was entered was used is a verb ,was entered is also a verb ,am i right

    asked on June 15, 2011
  91. Thermodynamics

    An intrepid explorer takes 400 g of ice from the cold Siberian environment, where the temperature is –40 degrees and places it in a kettle inside his mobile laboratory. The ice melts and he heats the water to +40 degrees. What is the total amount of heat

    asked on June 6, 2011
  92. chemistry dilutions

    you have 47 mL of a 2 M stock solution that must be diluted to .5 M how much water should you add

    asked on May 5, 2011
  93. reimbursement methodologies

    does anyone have answers to test 38181803 for penn foster

    asked on February 19, 2011
  94. penn foster

    Dr. Bob applies for medical staff privileges at General Hospital. The hospital administrator? A. is not required to look into Dr. Bob’s background. B. is required to query the National Practitioner Data Bank. C. is required to query the Data Bank unless

    asked on January 25, 2011
  95. grammar

    The informant, who will not be named, called in a tip last night informing police officers about an attempted robbery. The cold, dry, and ruthless wind lashed at their bare hands and faces. Are these sentences grammatically correct?

    asked on July 1, 2010
  96. math

    Elimination Method....I am not understanding this method either and need some help here is what I am working on: 1) x+8y=33 -x+4y=3 2) 5x+5y=-7 7x-2y=13 3) 0.3x-0.2y=4 0.5x+0.3y=-7/17 Can someone please help me with these!

    asked on March 13, 2010
  97. math

    simplify 9qt 9pt

    asked on October 3, 2009
  98. math

    3500 cm2=________L

    asked on October 3, 2009
  99. math

    3,500 cm2=_____L and simplify 10lbs 28oz

    asked on October 3, 2009
  100. math

    simplify 10 lbs 28 oz

    asked on October 3, 2009


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