Popular questions and responses by Sara
  1. statistics

    the probability that a house in an urban area will develop a leak is 5%. if 23 houses are randomly selected, what is the probability that none of the houses will develop a leak?

    asked on April 28, 2013
  2. math

    Two cars are side by side. One is 3.9 meters long. The other is 6% shorter. How long is the second car? I know the answer is 3.7, but how?

    asked on June 25, 2018
  3. math

    Find dy/dx and d2y/dx2. x = et, y = te−t

    asked on July 28, 2014
  4. Chemistry

    The compound M2X3 has a molar solubility of 0.0190 M. What is the value of Ksp for M2X3? Here are the choices: 1. 3.52 × 10^-6 2. 4.12 × 10^-5 3. 8.91 × 10^-8 4. 2.48 × 10^-9 5. 2.67 × 10^-7

    asked on April 27, 2014
  5. chemistry

    When the conductivity is at a minimum, what must be true about the amount of Ba(OH)2 compared to H2SO4? The Ba(OH)2 dissociates as Ba+2 + 2 OH-. H2SO4 dissociates as 2 H+ + SO4-2. Why does it not conduct at this low point? Why does it conduct more before

    asked on July 25, 2012
  6. math

    When 300 apple trees are planted per acre, the annual yield is 1.6 bushels of apples per tree. For every 10 additional apple trees planted, the yield reduces by 0.01 bushel per ten trees. How many apple trees should be planted to maximize the annual yield?

    asked on April 11, 2020
  7. business math

    Jen purchased a condo in Naples Florida for $699,000. She put 20% down and financed the rest at 5% for 35years. What are Jens total finance charge?

    asked on April 12, 2015
  8. Geometry

    30. PLis the angle bisector of KPM.Which can you conclude from this statement? You also can see this question number 30 on this website.Please add hyperlink. How answer is A and i want

    asked on July 31, 2020
  9. Chemistry

    Calculate the molarity and the molality of an NH3 solution made up of 30 g of NH3 in 70 g of water. The density of the solution is 0.982 g/ml. Molar Mass of NH3 = 17.04 g

    asked on December 2, 2010
  10. Geometry

    Based on the information in the diagram, can you prove that the figure is a parallelogram? Explain. a. Yes; opposite sides are congruent. b. Yes; opposite angles are congruent. c. No; you cannot prove that the quadrilateral is a parallelogram. d. Yes; two

    asked on July 21, 2020
  11. Geometry

    YZ = √ 5 and XZ = √ 2. Find XY. Answer in simplified radical form. It's a right triangle, Y vertex is 90 degree. plz help.

    asked on July 15, 2020
  12. English

    Read the passage. Zeke and Petra went to the horse show over the weekend, they said they saw Arabians and other breeds performing in the show ring. Which answer correctly explains what is incorrect about the passage? A. A comma splice is used to connect

    asked on May 12, 2020
  13. math (solid mensuration)

    A light is placed 5 ft. from the center of a globe 3 ft. in diameter. Find the area of the illuminated portion. thank you!

    asked on May 7, 2012
  14. math

    I am A number in the Last row on the hundreds chart. my ones digit is even.the differance between the ones digit and tens digit is 5.What number am i?

    asked on September 28, 2010
  15. Geometry

    YZ = √ 5 and XZ = √ 2. Find XY. Answer in simplified radical form. in the given triangle picture Y vertex is 90 degree. plz help.

    asked on July 14, 2020
  16. linear algebra

    Let T be the plane 2x−3y = −2. Find the shortest distance d from the point P0=(−1, −2, 1) to T, and the point Q in T that is closest to P0. Use the square root symbol '√' where needed to give an exact value for your answer. I need help with this

    asked on October 2, 2018
  17. chemistry

    Based upon the intermolecular forces present, rank the following substances according to the expected boiling point for the substance: MgF2, H2O, HCl, N2

    asked on April 3, 2014
  18. Geometry

    The diagonals of an isosceles trapezoid divided it into one pair of congruent triangles and one pair of similar triangles.

    asked on July 25, 2012
  19. Mendelian Genetics

    Assume you are performing a cross between a plant that is heterozygous for the dominant traits red flowers and wrinkled seeds, with a plant that is homozygous for the recessive traits white flowers and smooth seeds. Assume the alleles are R for red

    asked on January 20, 2015
  20. How many milliliters of a stock solution of 6.00 M

    How many milliliters of a stock solution of 6.00 M HNO3 would you have to use to prepare 0.190 L of 0.490 M HNO3? I used the equation M1V1=M2V2 6M*V1 = 0.190L*0.490 M lead me to this V1=0.190L*0.490M/6.00 M =0.0931 L per M/6.00M =0.0155166L

    asked on August 28, 2015
  21. science

    You know that a collision must be "elastic" if: The momentum of the two-object system doesn't change The sum of the final kinetic energies equals the sum of the initial kinetic energies There is no change in the internal energies of the objects (thermal

    asked on July 24, 2014
  22. math

    The value of Sara's new car decreases at a rate of 8% each year. 1.Write an exponential function to model the decrease in the car's value each month. 2.Write an exponential function to model the decrease in the car's value each week. 3.Write an exponential

    asked on November 17, 2017
  23. Chemistry

    From the equation below, how many grams of barium sulfate can be produced from 20.8 g of barium chloride? BaCl2 + Na2SO4 -> BaSO4 + 2NaCl

    asked on May 19, 2015
  24. U.S. History

    which of the following was not a weakness of the articles of confederation (1781-1789)? A) a week "league of friendship" among the states B) the requirement of unanimous approval by all 13 states for amendments C) no judicial branch D) no congressional

    asked on November 24, 2014
  25. Chemistry

    Given the thermodynamic data in the table below, calculate the equilibrium constant for the reaction: 2SO2(g)+O2--> 2SO3 Substance (DeltaH^o) (Delat S^o) SO2 -297 249 O2 0 205 SO3 -395 256 Answer (it was given) 2.32x10^24 Even though the answer is given

    asked on March 16, 2008
  26. math

    How many gram ofsodiun fluoride should be added to 100000liter of drinking water containing 0.6 ppm of sodium fluoride to provide a recommended concentration of 1.75 ppm

    asked on June 23, 2014
  27. DrBobb222 : Chemistry HElp...Please Check

    Standardization of the Sodium Thiosulfate Solution Make up a standard solution of potassium iodate by accurately “weighing by difference” about 0.1 g of KIO3 and placing it in your 100 mL volumetric flask. Fill the flask to mark with distilled water.

    asked on October 21, 2008
  28. Chemistry

    Elemental sulfur can be converted to sulfur dioxide by combustion in air. Sulfur dioxide will react with water to form sulfurous acid (see balanced equation below). SO2(g) + H2O(l) → H2SO3(l) What mass of sulfur dioxide is needed to prepare 29.36 g of

    asked on April 23, 2019
  29. math

    The formula of a trapezoid is A=1/2h(b1+b2) Express b1 in terms of A,h,and b2 I did A=1/2hb1+1/2hb2 A=hb1/2 +hb2/2 A-hb2(2/h)=hb1/2(2/h) A-b2=b1 I am not sure if this is correct? I was confused on how to do this. Any help or explanation is greatly

    asked on October 4, 2016
  30. chemistry 30a

    What volume (in mL) of an 8% w/v acetic acid solution would be needed to form 2.2 L of carbon dioxide gas at 25.2 degrees Celsius and 0.9982 atm? Assume the acid is reacted with excess sodium bicarbonate, and round your final answer to two sig figs.

    asked on March 12, 2012
  31. Science

    Which of the following is a characteristic of nonmetals? Nonmetals are often brittle solids. Nonmetals are often malleable. Nonmetals often conduct electricity. Nonmetals are often ductile.

    asked on November 17, 2015
  32. Advanced Functions

    he value of a new car depreciates at a rate of 12% per year. Write an equation to represent the approximate value of a car purchased for $23 000. Determine the value of the car two years after it is purchased. Approximately how many years will it take

    asked on January 12, 2011
  33. Math

    Jason was hired to mow a lawn that covers an area of 2 3/4 acres it took him 4 1/8 hours to complete the job what was his unit rate and hours per acre you multiply the numerator and a complex fraction by the reciprocal of the denominator to calculate our

    asked on February 7, 2018
  34. business math

    Andres Michael bought a new boat. He took out a loan for $23,980 at 3.75% interest for 4 years. He made a $4,470 partial payment at 4 months and another partial payment of $3,180 at 9 months. How much is due at maturity?

    asked on October 10, 2014
  35. Physics

    Multiple Concept Example 9 provides background pertinent to this problem. The magnitudes of the four displacement vectors shown in the drawing are A = 16.0 m, B = 12.0 m, C = 13.0 m, and D = 23.0 m. Determine the (a) magnitude and (b) direction for the

    asked on May 29, 2012
  36. finance

    Assume that the export price of a Nissan XTerra from Osaka, Japan is ¥3,750,000. The exchange rate is ¥121.84/$. The forecast rate of inflation in the United States is 2.8% per year and is 0.6% in Japan. a. What is the export price of the XTerra at the

    asked on May 5, 2011
  37. chem

    How many moles of O are in 13.0 mol Fe(NO3)3? can you please find this using dymensional analysis and show me how you worked it? Thans

    asked on November 10, 2010
  38. Socials

    How did Napoleon help to spread feelings of nationalism throughout Europe? Explain why you think nationalism is a positive or negative force, or both. Napoleon helped to spread feelings of nationalism throughout Europe by initially using it to help him

    asked on November 9, 2009
  39. chemistry

    Using your answer from Part A, calculate the volume of a mole of Na atoms (in cm3/mol ). Assume that the entire volume is occupied by Na atoms leaving no gaps or holes between adjacent atoms. (Answer A is V= 2.70*10^7)

    asked on November 10, 2008
  40. Maths

    A boy spends 1/4 of his money on sweets and 1/3 on computer games. What fraction of his money does he not spend?

    asked on April 11, 2017
  41. Chemistry

    CoCl2CO+Cl2 Keq=7.6*10^-4 M CoCl2 is introduced in a closed container until its concentration is .890 M. What will be the concentration of Cl2 once the reaction has reached equilibrium?

    asked on July 20, 2013
  42. Calculus

    Calculate the height of a cylinder of maximum volume that can be cut from a cone of height 20 cm and base radius 80 cm , please help me

    asked on December 25, 2011
  43. science

    how does a magnitude-8.0 earthquake could be classified as a low-intensity earthquake? LAST SCIENCE QUESTION!

    asked on April 1, 2009
  44. math

    The height of a frustum of a pyramid is 12 and the areas of its bases are 9 and 25. What is the volume of the frustum?

    asked on March 22, 2020
  45. Math

    Marie forgot the formula for finding the area of a circle, so she divided the circle into sectors and created a parallelogram-shaped figure. What should she use as the height of the figure? A.the radius B.360 C.12 of the circumference D.the circumference

    asked on February 21, 2020
  46. Math

    Form the perfect square trinomial in the process of completing the square. What is the value of c? x^2 + 3x + c = 7/4 + c c =

    asked on May 22, 2016
  47. chemestry

    consider the reaction 2N2O(g) == O2(g)+2N2(g).which of the following will cause a shift in the equilibrium to the left?

    asked on November 1, 2014
  48. Chemistry

    The complex [Co(ox)3]4- has a high-spin electron configuration. How many unpaired electrons are there in the complex? I know because it's a high-spin, it's tetrahydral shaped. But I don't know what (ox) is so, I'm stuck in finding the oxidation state of Co

    asked on July 26, 2013
  49. Chemistry

    Calculate how much acetylene (C2H2) can be produced from 358 g of H20 and an excess of CaC2 if the perfect yield for this reaction is 94.5% CaC2+H2)-> C2H2+C2H2+CA(OH)2

    asked on July 20, 2013
  50. Chemistry

    Dinitrogen pentoxide, N2O5, decomposes by first-order kinetics with a rate constant of 0.15 s-1 at 353 K. (a) What is the half-life (in seconds) for the decomposition of N2O5 at 353 K? (b) If [N2O5]0 = 0.0579 mol·L-1, what will be the concentration of

    asked on June 28, 2013
  51. Calculus - HELP plz!

    Find all of the first partial derivatives of f(x,y,z)=arctan y/xz

    asked on June 2, 2013
  52. Chemistry

    How much of NaOH (in grams) is needed to prepare 546 mL of solution with a pH of 10.00 ?

    asked on February 16, 2011
  53. chem

    Which of the following elements would you expect to gain electrons in chemical changes? (Select all that apply.) gold chromium zirconium nitrogen iodine

    asked on September 21, 2010

    Which of the problems in the construction of the CPI might be illustrated by each of the following situations? Explain. a. the invention of the Sony Walkman b. the introduction of air bags in cars c. increased personal computer purchases in response to a

    asked on April 12, 2009
  55. Algebra

    The lesser of two consecutive even integers is 10 more than one-half the greater. Find the integers.

    asked on October 1, 2007
  56. statistics

    The professor teaching a large introductory class gives a final exam that has alternate forms, A, B, and C. A student taking the exam using Form B is upset because she claims that Form B is much harder than Forms A and C. Discuss how percentile point data

    asked on April 22, 2017
  57. Physics

    A flywheel turns through 60 rev as it slows from an angular speed of 2.8 rad/s to a stop. How much time is required for it to complete the first 30 of the 60 revolutions?

    asked on March 6, 2017
  58. Chemistry

    Sulfur dioxide reacts with chlorine to produce thionyl chloride and dichlorine oxide S: 32.0 amu O: 16.0 amu Cl: 35.45 amu SO2 + 2Cl2 --> SOCl2 + Cl2O If 0.400 moles of chlorine gas reacts excess sulfur dioxide, how many moles of dichlorine oxide are

    asked on May 1, 2015
  59. science

    A car of mass 2900 kg collides with a truck of mass 4800 kg, and just after the collision the car and truck slide along, stuck together. The car's velocity just before the collision was < 34, 0, 0 > m/s, and the truck's velocity just before the collision

    asked on June 25, 2014
  60. econ

    The terms below are measures or individual components of the money supply. Specifically considering the money supply of the United States, rank these items from largest to smallest in terms of dollar value. Currency, M2,M1,Balances in savings accounts,

    asked on March 27, 2014
  61. Chemistry

    A sample of oxygen is collected over water at 22 C and 762 torr. What is the partial pressure of the dry oxygen? The vapor pressure of water at 22C is 19.8 torr.

    asked on July 20, 2013
  62. Statistics

    Solve the following problems by using the binomial formula. a. If n = 4 and p = .10 , find P(x = 3) . b. If n = 7 and p = .80 , find P(x = 4) . c. If n = 10 and p = .60 , find P(x ¡Ý 7) . d. If n = 12 and p = .45 , find P(5 ¡Ü x ¡Ü 7) .

    asked on July 29, 2011
  63. chemistry

    In the reaction between CV+ and –OH, one species is acting as the Lewis base, the other as the Lewis acid. (Note: A Lewis acid is not necessarily a proton donor. It is, however, always an electron pair acceptor). Which reagent is the Lewis acid? A. CV+

    asked on July 13, 2010
  64. math

    A regular triangular pyramid has slant height 6 cm and base edges of length 15 cm. Find the volume of the pyramid and the surface area.

    asked on February 27, 2020
  65. Science

    When hair is combed with a hard rubber comb, the hair becomes positively charged because the comb A. Transfers protons to the hair B. Remove electrons from the hair C. Transfers electrons to the hair D. Remove both times from the hair I could be removed

    asked on February 11, 2016
  66. Chemistry

    Which of the following elements is least likely to form a cation that will then form an ionic bond with an ion of a Group 7A element? S K Rb Fr

    asked on December 1, 2015
  67. Business Math

    Andres Michael bought a new boat. He took out a loan for $23,980 at 3.75% interest for 4 years. He made a $4,470 partial payment at 4 months and another partial payment of $3,180 at 9 months. How much is due at maturity?

    asked on October 10, 2014
  68. Empires

    I need help to compare and contrast the Babylonian and Hittite empires

    asked on September 22, 2014
  69. CALCULUS-plz help!

    For the curve r = 2 sin 3(theta): Find the arc length of one petal

    asked on April 16, 2013
  70. Social Studies

    The 1978 Supreme Court decision in Bakke v. Regents of the University of California A. ruled in favor of affirmative action within specified limits. B. established the "red state-blue state" divide. C. established the rights of students to appeal college

    asked on August 22, 2012
  71. Math

    A science museum requires 3 adult chaperones for every 15 students on a field trip. How many chaperones would be needed for a group of 125 students?

    asked on March 24, 2011
  72. Chemistry

    A solution of 2.50 g of a compound having the empirical formula C6H5P in 25.0 g of benzene(C6H6) is observed to freeze at 4.3 degrees C. Calculate the molar mass of the solute and its molecular formula.

    asked on December 3, 2010
  73. Math

    Mary buys 8 widgets for $40.00. She adds $1.00 in enhancements to each widget and sells them for $9.00 each. What is Mary's estimated gross profit margin? 25% 33% 39% 44% 50% 67$

    asked on August 13, 2010
  74. Physics

    A car is traveling along a straight road at a velocity of +31.0 m/s when its engine cuts out. For the next ten seconds, the car slows down further, and its average acceleration is a1. For the next five seconds, the car slows down further, and its average

    asked on November 30, 2008
  75. math

    Find how many six-digit numbers can be formed from the digits 2, 3, 4, 5, 6 and 7 (with repetitions), if: the numbers formed must be divisible by 25

    asked on April 25, 2020
  76. Chemistry

    Restart the PhET simulation and set it up in the following manner: select Oscillate, select No End, and use the parameters in parentheses by sliding the bars for Amplitude (1.00 cm), Frequency (1.20 Hz ), Damping (none), and tension (highest). Using the

    asked on October 18, 2018
  77. Please help

    Which best describes Hitler's beliefs as expressed in Mein Kampf? Revolution was needed to create a classless society. Germany could control the world with the help of the Japanese. All races could live peacefully under German domination. Jewish people

    asked on May 13, 2015
  78. History

    what are two themes that would be appropriate for thematic time lines of important events from prehistory to A.D.1600.

    asked on January 18, 2015
  79. calculus

    A street light is mounted at the top of a 6-meter-tall pole. A man 2 m tall walks away from the pole with a speed of 1.4 m/s along a straight path. How fast is the tip of his shadow moving when he is 16 m from the pole?

    asked on October 16, 2012
  80. math

    what is the largest negative coterminal angle of -417?

    asked on August 16, 2011
  81. CHemistry Help pleaseee

    Imagine that you have a 6.00 L gas tank and a 3.00 L gas tank. You need to fill one tank with oxygen and the other with acetylene to use in conjunction with your welding torch. If you fill the larger tank with oxygen to a pressure of 115 atm, to what

    asked on October 13, 2008
  82. physics

    A car travels on a straight road for 40km at 30km/h. It then continues in same direction for 40km at 60km/h. a)What is the average velocity of the car during the 80km trip?(assume it moves in positive x direction) b)What is the average speed? c)graph and

    asked on September 10, 2006
  83. chemistry

    For the following reaction at equilibrium in a closed vessel, ΔrH = −153 kJ per mol of CH3CHO. CH3CHO(g) ⇌ CH4(g) + CO(g) Which of the following statements are correct? a. For the thermodynamic equilibrium constant, K at 298 K is greater than K at 500

    asked on April 8, 2020
  84. math

    A sphere of radius 3 is inscribed in a cylinder. What is the volume inside the cylinder but not inside the sphere?

    asked on March 5, 2020
  85. math

    A regular square pyramid has a height of 2 and lateral edges of length 10. What is the lateral area and total surface area of the pyramid?

    asked on February 27, 2020
  86. Physics

    I need help with this question with explanation. Thanks A particle of mass m starts from rest at position x = 0 and time t = 0. It moves along the positive x-axis under the influence of a single force Fx = bt, where b is a constant. The velocity v of the

    asked on December 19, 2019
  87. english 3

    huck mentions that he wishes the widow douglas could know about his efforts to save the men on the wreck of the walter scott. pretend that you are huck and write a letter to the widow, explaining the situation and what you did about it. try to copy the

    asked on August 2, 2019
  88. physics

    If 335 g of water at 65.5 °C loses 9750 J of heat, what is the final temperature of the water? Liquid water has a specific heat of 4.18 J/(g.°C). °C (Answer a number only, no units. Round to the tenth place). This is an example of an endothermic or

    asked on May 22, 2017
  89. algebra

    Bob needs to wash the windows on his house. He has a 25-foot ladder and places the base of the ladder 10 feet from the wall on the house. How far up the wall will the ladder reach?

    asked on November 27, 2016
  90. Chemistry

    In which of the following substances does sharing of electrons between two atoms occur? He Nal PO43– Ag

    asked on December 1, 2015
  91. Chemistry

    When the following reaction took place at 23.8 and a pressure of 758 torr, 3.9 L of o2 were collected. What mass of KCIO3 decomposed? KCIO3->KCI+O2

    asked on July 20, 2013
  92. physics

    Calculate the magnitude of the gravitational force between the Earth and an m = 6.00 kg mass on the surface of the Earth. The distance to the center of the Earth from the surface is 6.37×103 km and the mass of the Earth is 5.98×1024 kg. B)Calculate the

    asked on March 22, 2013
  93. chemistry help!!

    The half-life for the process 238U 206Pb is 4.5 109 yr. A mineral sample contains 45.9 mg of 238U and 16.8 mg of 206Pb. What is the age of the mineral? i used the equation: n(T)=n(O)/2^(t/halflife) and i got 6.53e9 but it is wrong. what am i doing wrong?

    asked on September 5, 2012
  94. MATH

    You wish to mentally estimate the total cost of items that have the following prices: $1.85, $.98, $3.49, $9.78, and $6.18. Rounding off the items to the nearest half-dollar, your estimate of the total cost of these items is A. $22.50. B. $22.30. C.

    asked on August 18, 2012
  95. Math

    What words have a horizontal line of symmetry when printed horizontally, and a vertical line of symmetry when printed vertically. The only word I have is HI.

    asked on February 5, 2010
  96. calc

    If 4x2+3x+xy=2 and y(2)=–10 , find y'(2) by implicit differentiation. i keep getting the wrong answer for this problem evn when plugging 2 in for y.

    asked on May 9, 2008
  97. chem

    A 1.0 M solution of an unknown weak base has a pH of 12.3 at 25 oC. What is the identity of the base? a. Ammonia, pKb = 4.8 b. Aniline, pKb = 9.5 c. Methylamine, pKb = 3.4 d. Pyridine, pKb = 8.8

    asked on April 8, 2020
  98. Math

    When a class took a math test, 15% of the class failed, 25% made some mistakes (but didn’t fail), and 24 students got perfect scores. How many students were in the class?

    asked on February 23, 2017
  99. Percentage

    A flat-screen TV costs $1,400. The TV is on sale for 35% off. What's the discount price?

    asked on January 4, 2017
  100. physic

    The position function x(t) of a particle moving along an x axis is x = 6.00 - 8.00t2, with x in meters and t in seconds. (a) At what time and (b) where does the particle (momentarily) stop? At what (c) negative time and (d) positive time does the particle

    asked on September 26, 2015


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