Popular questions and responses by Natalie
  1. chemistry

    Arrange the following aqueous solutions in order of decreasing freezing points (lowest to highest temperature): 0.10 m Na3PO4, 0.35 m NaCl, 0.20 m MgCl, 0.15 m C6H12O6 and 0.15 m CH3COOH.

    asked on July 20, 2015

    A and B run around a circular track whose cicumference is 150m. when they run is opposite directions they meet every 5 seconds, but when they run in the same direction from the some point they are together every 25 seconds. what are their rates? ans. 18m/s

    asked on June 20, 2015
  3. science

    Name the type of reaction that the equation represents? 2Cu + O2 -------> 2CuO

    asked on February 11, 2012
  4. College Physics

    In a crash test, a 2000-kg van collides with a concrete support. The stopping time interval for the collision is 0.10 s, and the impulse exerted by the support on the van is 7.0×103N⋅s. A.) Determine the magnitude of the change in momentum. B.)Determine

    asked on October 2, 2018
  5. chem

    A sample of oxygen gas was collected via water displacement. Since the oxygen was collected via water displacement, the sample is saturated with water vapor. If the total pressure of the mixture at 26.4 °C is 725 torr, what is the partial pressure of

    asked on April 15, 2014
  6. Physics

    a 0.30-m radius automobile tire rotates how many rad after starting from rest and accelerating at a constant 2.0 rad/s^2 over a 3.54-s interval

    asked on April 20, 2015
  7. math

    A ball is thrown vertically upward with an initial velocity of 5 ft/sec from a height of 20 feet. Which function models its motion? i literally am lost and have no idea how to this problem. if i could have help with the steps on how to do the problem and

    asked on November 21, 2014
  8. Chemistry

    How many mL of 1.20 M H2SO4 are needed to neutralize 18.75 mL of 0.843 M LiOH?

    asked on July 11, 2017
  9. Chemistry

    (NH4)2S is a strong electrolyte. Determine the concentration of each of the individual ions in a 0.200 M (NH4)2S solution. [NH4] = M [S] = M

    asked on April 3, 2014
  10. statistics

    Can someone help me with this questions. Find the variance for a given data. Rpund your answer to one more decimal place then the original data. Compute the variance. Jeanne is currently taking college zoology. The instructor often gives quizzes. On the

    asked on August 28, 2007
  11. Math

    Jamie spenta total of $11.60 on 5dentical pens and a ruler .A rulercost$1.30less than a pen .how much did a pen cost?

    asked on April 9, 2017
  12. Chemistry

    For the reaction, 2SO2(g) + O2(g) ¨ 2SO3(g) + heat, at equilibrium, what will be the effect on the net amount of SO3 present if the temperature of the container is increased? A) The concentration of SO3 decreases. B) The concentration of SO3 increases.

    asked on March 12, 2010
  13. Chemistry

    -Consider the reaction when aqueous solutions of silver(I) nitrate and manganese(II) chloride are combined. The net ionic equation for this reaction is? -Consider the reaction when aqueous solutions of cobalt(II) sulfate and lead(II) nitrate are combined.

    asked on March 5, 2018
  14. Precalculus with Trigonometry

    Prove or disprove the following identity: (sin(10x))/(sin(x)+sin(9x)) = (cos(5x))/(cos4x))

    asked on April 4, 2013
  15. algebra 1

    a bout travels 280 miles downstream and back. The trip downstream took seven hours. The trip back took 14 hours. The speed of the boat in still water and the speed of the current

    asked on January 13, 2016
  16. Calculus 2

    Find the area bounded by the curves y=sin(4x) and y=0 for x between x=0 and x=3pi/8.

    asked on January 29, 2018
  17. English

    In the sentence "There comes a time when the cup of endurance runs over, and men are no longer willing to be plunged into an abyss of injustice," the bolded phrase creates a mood of __________ among the audience A.Panic B.Despair C.Anger D.Anticipation

    asked on December 2, 2015
  18. History

    In Uncle Tom's Cabin, (the book) did blacks have a racial caste system? Please explain

    asked on July 19, 2014
  19. Chemistry

    Iodine 131 is a radioactive isotope. After 4.00 days, 70.8% of a sample of 131I remains.What is the half life of 131I?

    asked on April 26, 2014
  20. Physics

    A Jaguar XK8 convertible has an eight-cylinder engine. At the beginning of its compression stroke, one of the cylinders contains 499 cm ^ 3 of air at atmospheric pressure (1.01\times 10^5 Pa}) and a temperature of 27.0 degrees C. At the end of the stroke,

    asked on November 12, 2012
  21. Math

    Jill and Matt run on a 400-meter-long oval track. They each run 10 laps daily and both run in the same lane. One day, they begin at the same point, but ran in opposite directions. Jill ran at a constant speed that was 2 meters per second faster than Matt's

    asked on October 22, 2008
  22. Calculus I

    Hello, The pressure P and volume V of an expanding gas are related by the formula PVb=C, where b and C are constants (this holds in adiabatic expansion, without heat gain or loss). Find dPdt if b=1.6, P=12kPa, V=80cm2, and dVdt=20cm3/min. Thus far, I got

    asked on April 10, 2015
  23. Chemistry

    Calculate the change in the enthalpy of the reaction. C4H4(g)+2H2(g)===>C4H8(g) Use the following: change in enthalpy of combustion for: C4H4=-2341 kJ mol-1 H2=-286 kJ mol-1 C4H8=-2755 kJ mol-1

    asked on October 25, 2009
  24. Math--Area

    Find the area of each regular polygon to the nearest tenth. Octagon with side length of 10 kilometers. Heres what I tried; but I don't know if im on the right track. Area=1/2 * Perimeter* Apothem Perimeter=base of octagon* number of sides Perimeter=10*8=80

    asked on April 4, 2007
  25. English

    Which adjectives to describe an intense feeling about something

    asked on January 9, 2020
  26. Chemistry

    If it takes 22.75 mL of 1.75 M H3PO4 to neutralize 14.90 mL of Al(OH)3, what is the molarity of the Al(OH)3?

    asked on July 11, 2017
  27. Math

    a regular plot of land is designed so that its length is 6 meters more than its width. the diagonal of the land is 10 meters. to the nearest tenth of a meter, what are the dimensions of the land?

    asked on May 6, 2016
  28. Calc

    A cup of coffee at 90 degrees celsius is put into a 30 degree celsius room when t =0 . The coffee's temperature, f (t ) , is changing at a rate given by f '(t )=-8(0 .8) t degrees celsius per minute, where t is in minutes. Estimate the coffee's temperature

    asked on July 21, 2014
  29. CHemistry

    Calculate the pH of a .25 M ammonium acetate (CH3COONH4) soluton. I thought u just did -log(.25) but it keeps saying that i have the wrong answer.

    asked on December 8, 2010
  30. College Physics

    You are on vacation in San Francisco and decide to take a cable car to see the city. A 6100-kg cable car goes 410 m up a hill inclined 16 ∘ above the horizontal. The system is the car and Earth. Determine the change in the total energy of the system when

    asked on October 15, 2018
  31. Math

    write an inequality to represent the situation: The temperature stayed above -15

    asked on April 2, 2018
  32. Calculus II

    Sketch the region enclosed by 2y=5x^(1/2), y=3, 2y+4x=9. Decide whether to integrate with respect to x or y, and then find the area of the region.

    asked on January 29, 2018
  33. math please help me!

    Estimate the instantaneous rate of change of the function f(x) = x ln x at x = 1 and at x = 3. (Use h = 0.1, 0.01, 0.001, 0.0001, and so on. Round your answers to four decimal places.) f '(1) = f '(3) = What do these values suggest about the concavity of

    asked on September 16, 2015
  34. math! please help!

    For a boat to float in a tidal bay, the water must be at least 2.7 meters deep. The depth of the water around the boat, d(t), in meters, where t is measured in hours since midnight, is d(t) = 5 + 4.6 sin(0.5t). (a) What is the period of the tides in hours?

    asked on September 2, 2015
  35. Chemistry

    A piece of copper metal is initially at 100 C. It is dropped into a coffee cup calorimeter containing 50.0 g of water at a temperature of 20 C. After stirring, the final temperature of both copper and water is 25 C Assuming no heat losses, and that the

    asked on November 16, 2012
  36. Physics

    An Earth satellite moves in a circular orbit at a speed of 5800 m/s. a)What is the radius of the satellite's orbit? b) What is the period of the satellites orbit in hours?

    asked on October 23, 2012
  37. physics

    A mass of 2.6 kg lies on a frictionless table, pulled by another mass of 4.7 kg under the influence of Earth’s gravity. The acceleration of gravity is 9.8 m/s2 .If the acceleration of the object has a magni- tude of 3.5 m/s2, what is the angle θ between

    asked on October 12, 2012
  38. phsical science

    a tire contains air ata pressure of 2.8 bar at 10 degree celsius.if the tires volume is unchanged what will the air pressure in it be when the tire warms up to 35 degree celsius if the car is driven.

    asked on June 20, 2012
  39. chemistry

    What is the original molarity of an aqueous solution of ammonia (NH3) whose pH is 11.10 at 25 degrees C? (Kb for NH3=1.8 x 10^-5)

    asked on December 8, 2010
  40. Chemistry

    A mole of methane reacts with 64g of oxygen at 1 atm, 425 K. There are two ways in which methane can react with oxygen. It can either form water vapor and carbon dioxide or water vapor and carbon monoxide. After reaction the final gas density is 0.7282

    asked on November 18, 2010
  41. math

    What is the cube root of x to the 7th power?

    asked on October 14, 2010
  42. geometry

    If the area of Triangle T, sides 5,12, and 13 equals the area of rectangle R, width 3, then what is the perimeter of rectangle R?

    asked on April 26, 2009
  43. algebra

    Rectangle R is formed by joining the centers of two congruent tangent circles and then drawing radii perpendicular to a common external tangent. If the perimeter of R is 60, what is its area?

    asked on August 27, 2008
  44. math

    . A jacket costs $94.95. It is on sale for 30% off. Estimate the sale price.

    asked on May 17, 2015
  45. Chemistry

    Predict which compound will have the higher boiling point and explain how you made your choice by including intermolecular forces. 1. H2O or CH2O 2. CS2 or CH4

    asked on May 12, 2014
  46. Chemistry

    What would be the speed of the following particles if they had the same wavelength as a photon of green light (λ = 500.0 nm)? Proton (mass = 1.673*10^(-24)g) =_____ neutron (mass = 1.675*10(-24)g) =_____ electron (mass = 9.109*10^(-28)g) =_____ alpha

    asked on October 10, 2013
  47. Language Arts

    3 main points for a speech on the alphabet

    asked on September 30, 2013
  48. Stats

    A large population has a mean of 200 and a standard deviation of 40. Which one of the following best describes the percentage of measurements that fall in an interval that is within two standard deviations of the mean?

    asked on September 14, 2012
  49. Chemistry

    1) A compound has the following percentages by mass: barium, 58.84%; sulfur, 13.74%; oxygen, 27.43%. Determine the empirical formula of the compound. 2) If a 1.271-g sample of aluminum metal is heated on a chlorine gas atmosphere, the mass of aluminum

    asked on December 30, 2011
  50. Biology

    What is the biological importance of what you observed? I observed different solutions pH levels (like water, skim milk, phosphate buffer, etc) before and after adding acid. I also observed different antacid solutions (alka-seltzer, tums, etc) to see how

    asked on September 3, 2019
  51. Math

    I have 25 ones and 3 tens.

    asked on July 22, 2019
  52. math

    For tax purposes, you may have to report the value of your assets, such as cars or refrigerators. The value you report drops with time. "Straight-line depreciation" assumes that the value is a linear function of time. If a $1020 refrigerator depreciates

    asked on August 27, 2015
  53. math

    A real estate agent receives a 9% commission for every house sold. Suppose she sold a house for $112,000. Estimate her commission.

    asked on May 17, 2015
  54. BOB

    A sphere of radius 20 cm and mass 1.80 kg starts from rest and rolls without slipping down a 30.0 degree incline...

    asked on March 10, 2015
  55. science

    1.40g each of CO, H2O, and H2 are sealed in a 1.41−L vessel and brought to equilibrium at 600 K. CO(g)+H2O(g)⇌CO2(g)+H2(g)KC=23.2 How many grams of CO2 will be present in the equilibrium mixture?

    asked on March 10, 2015
  56. english

    why is sasha in trouble in the story "a problem"

    asked on October 10, 2014
  57. Physics

    Suppose that the swimmer in the figure below has a swimming speed relative to the water of 0.45 m/s, while the speed of the current is 2.0 m/s. If it takes the swimmer 160 s to cross the river, how wide is the river?

    asked on September 24, 2014
  58. chemistry

    What is the density (in grams per liter) of a gas at STP if 4.16 L of the gas in a bulb at 43.7 °C, and 737.9 mm Hg weighs 0.262 g?

    asked on April 13, 2014
  59. chemistry

    Knowing the concentration of a solution allows us to find all of the following except A. the mass of a solute. B. the mass of the solvent. C. the volume of the solvent. D. the concentration of a solution when conditions change.

    asked on March 19, 2014
  60. Math

    Jen-Min wants to enlarge a 4 inch by 6 inch photo so that the longer side will be forteen inch how long will the shorter side be?

    asked on January 18, 2013
  61. Accounting

    T/F Questions The main reason that the bank statement cash balance and the company's cash balance do not initially balance is due to timing differences. Sales Discounts is a revenue account with a credit balance. Multiple Choice: Assuming a 360-day year,

    asked on April 28, 2012
  62. Physics

    From t = 0 to t = 5.00 min, a man stands still, and from t = 5.00 min to t = 10.0 min, he walks briskly in a straight line at a constant speed of 2.3 m/s. (a) What is his average velocity vavg in the interval 2.000 min to 7.90 min? I found this to be 1.15

    asked on September 5, 2011
  63. physics

    As some molten metal splashes, one droplet flies off to the east with initial speed vi at angle θi above the horizontal, and another droplet flies off to the west with the same speed at the same angle above the horizontal, as inthe figure. In terms of vi

    asked on October 15, 2010
  64. 8th grade

    robert has a piece of twine 3/4 yards long. he needs a piece of twine that is 2/3 of this length. how long of a piee of twine does robert need?

    asked on August 17, 2010
  65. HELP!!!!!

    What is the first step in solving the problem, 3x-8/12=9? A) Add 8 to both sides. B) Multiply by 12 on both sides. C) Divide by 3 on both sides. D) Subtract 9 on both sides.

    asked on November 12, 2009
  66. Chemistry

    Calculate the standard enthalpy of formation of CuO2, given that: 2Cu2O + O2 ==> 4 CuO (-288 kJ) Cu2O ==> Cu + CuO (11 kJ) PLEASE HELP!!!!

    asked on October 26, 2009
  67. chem

    plz help If you carefully place a steel razor blade flat on the surface of water, the razor blade can be made to float. Explain this result, given that the density of steel is much greater than that of water. I'm not really sure what the answer is. I think

    asked on April 18, 2007
  68. Math

    A pizza shop charges $2.00 for a slice that is one-eighth of a pizza and $3.00 for a slice that is one-fourth of a pizza. One day the pizza shop makes 6 pizzas. How much more money will they make if they slice all the pizzas into eighths than if they slice

    asked on November 29, 2018
  69. History

    Please complete this chain of events. Match the Earliest event to the lowest number, and so on. Protests erupt in the Colonies over Boston Massacre (1) Sons of Liberty organize Boston Tea Party protest (3) British government passes the Intolerable Acts to

    asked on October 28, 2018
  70. Math

    Evaluate Integral 0 to 2pi (3t+2)sin(t^3+2t+1)dt if possible

    asked on September 7, 2018
  71. chemistry

    6NH3 + 2H2BO3-3N2H4 + 2B+ 4H2O+ 2OH- name of the element oxidized:? name of the element reduced:? formula of the oxidizing agent:? formula of the reducing agent:? 3N2H4 + 2ClO3-3N2 + 2Cl-+ 6H2O name of the element oxidized:? name of the element reduced:?

    asked on March 20, 2018
  72. chemistry

    1) A Galvanic cell runs on the following reaction: Co (s) + Cu2+ (aq) → Co2+ (aq) + Cu (s) Draw a diagram for this Galvanic cell, labeling the electron flow, the anode and cathode, and the positive and negative sides of the Galvanic cell. 2) A Galvanic

    asked on January 25, 2017
  73. fedreal government

    Which of the following statements about the Articles of Confederation is UNTRUE? a. It was the second official constitution used to govern America b. It was the first official constitution used to govern America c. Power was too decentralized d. It

    asked on August 11, 2016
  74. math

    a room measures 22 feet by 28 feet. They are covering the floor with square tiles that measure 1 foot on a side and cost ​$0.89 each. How much will they spend on the​ tile?

    asked on May 16, 2016
  75. algebra 1

    does 4x+5y=0 represent a direct variation? if so, find the constant of variation. complete the steps to solve 4x+5y=0 for y.

    asked on February 18, 2016
  76. math

    The desert temperature, H, oscillates daily between 36°F at 4 am and 56°F at 4 pm. Write a possible formula for H in terms of t, measured in hours from 4 am. I thought the answer is -10cos(1/6pi times t) +46 but it got marked wrong. I thought that the

    asked on September 2, 2015
  77. Math

    Consider the functions in the figure below. Find the coordinates of C in terms of b. So there are two functions. There is the y=x^2 u-shape and then a line in the middle of it with points (0,b) and (1,1) in that order from left to right. Farther to the

    asked on August 27, 2015
  78. math

    . Estimate the sales tax and final cost of a book that costs $12.95 with a sales tax of 6%.

    asked on May 17, 2015
  79. Physics

    A 2.0kg object initially at rest explodes breaking into two pieces of mass 5.0kg and 15.0kg. If the 15.0kg piece moves with a speed 2m/s what is the speed of the 5.0kg piece? A. -6 m/s B. 15 m/s C. -5 m/s D. 20 m/s

    asked on April 6, 2015
  80. Physics

    Two blocks are connected by a string on a pulley. One block is on an incline, and the other is hanging. The smooth inclined surface makes an angle of 35 ∘ with the horizontal, and the block on the incline has a mass of 5.7 kg. The mass of the hanging

    asked on February 25, 2015
  81. physics

    Bobo jumps out of a plane 2,000 m in the air. If Bobo has a mass of 100 kg, how much kinetic energy will he have after falling for 200 m? Assume no air resistance.

    asked on November 4, 2014
  82. Fractions

    Fiona and camila took a load of peaches to the farmers market. During the first hour , they sold 1/2 of the peaches plus 1/2 of a peach. In the second hour, they sold 1/3 of the remaining peaches plus 1/3 of a peach. In the third hour , they sold 1/4 of

    asked on October 26, 2014
  83. Math

    How do I find the points, so that O can graph it. y=1/4x+4

    asked on July 27, 2014
  84. calculus

    Find a point c satisfying the conclusion of the Mean Value Theorem for the function f(x)= x^1/3 on the interval [1,8] I got f'(c)= 1/7 but am not sure where to go from there.

    asked on July 22, 2014
  85. Math

    Which expression is equivalent to 9(4+r)?

    asked on April 22, 2014
  86. Maths

    WhAt is x 3x9^x=81

    asked on December 1, 2013
  87. Chemistry

    Assume that the normal blood buffer contains 0.00080 M carbonic acid and 0.0085 M hydrogen carbonate, the pKa = 6.35 for carbonic acid and the volume of blood in the body is 7.00 L. The blood pH, due to disruption is now 7.20. What is the ratio of

    asked on November 11, 2013
  88. Chemistry

    If you need to prepare 250.0 mL of a pH 5.00 buffer that has a total buffer concentration of acetic acid + sodium acetate of 0.050M, how many moles of each will you need to prepare the solution? Given solutions of acetic acid and sodium acetate with

    asked on November 11, 2013
  89. Physics -URGENT-

    A 55 kg boy and a 37 kg girl use an elastic rope while engaged in a tug-of-war on a frictionless icy surface. If the acceleration of the girl toward the boy is 2.4 m/s^2, determine the magnitude of the acceleration of the boy toward the girl in m/s^2

    asked on October 6, 2013

    55 kg boy and a 37 kg girl use an elastic rope while engaged in a tug-of-war on a frictionless icy surface. If the acceleration of the girl toward the boy is 2.4 m/s 2 , determine the magnitude of the acceleration of the boy toward the girl in m/s^2

    asked on October 6, 2013
  91. math

    Triangle ADE is inside rectangle ABCD. Point E is half way between points B and C on the rectangle. Since AB is 8 cm and side AD is 7 cm. 1. what is the area of triangle ADE? 2. what is the ratio of the area of the triangle ABE to the area of triangle ADE?

    asked on April 14, 2013
  92. Precalculus with Trigonometry

    Graph f(x) = sin(3x)/sin(x) - cos(3x)/cos(x) and make a conjecture. Prove your conjecture.

    asked on April 7, 2013
  93. math

    A model of a park was built on scale of 1.5cm to 50m. If the distance between two trees in the park is 150m, what is the distance on the model?

    asked on April 6, 2013
  94. Precalculus with Trigonometry

    Prove or disprove the following Identities: cos(-x) - sin(-x) = cos(x) + sin (x) sin raised to the 4 (theta) - cos raised to the 4 (theta) = sin squared (theta) - cos squared (theta) cos (x+(pi)/(6)) + sin (x - (pi)/(3)) = 0 cos(x+y)cos(x-y) = cos squared

    asked on April 4, 2013
  95. Physics

    A transformer has 25 turns in the primary coil and 200 turns in the secondary coil. If 12 V is connected to the primary coil and a 20-Ω device is connected to the secondary coil, calculate the current in Amperes passing through the device.

    asked on March 17, 2013
  96. Physics

    The primary of a step-down transformer connected to a 240 V source has 1000 turns. The secondary has 100 turns. What is the output voltage of this transformer?

    asked on March 17, 2013
  97. math

    A rope is used to hold a tree upright. it is attached to the ground at a distance of 95 feet from the tree and forms an angle of 47 degree with the ground. How long is the rope to the nearest foot?

    asked on February 12, 2013
  98. Chemistry

    A piece of copper metal is initially at 100 C. It is dropped into a coffee cup calorimeter containing 50.0 g of water at a temperature of 20 C. After stirring, the final temperature of both copper and water is 25 C Assuming no heat losses, and that the

    asked on November 16, 2012
  99. Physics PLEASE HELP!

    How many molecules are there in 0.029 moles of carbon dioxide gas, CO2? I asked this today, and the person told me to do 0.029 * 6.022e23 and my answer was wrong :/ Can someone please tell me what my answer should be!!?

    asked on June 20, 2012
  100. Physics

    How many molecules are there in 0.029 moles of carbon dioxide gas, CO2?

    asked on June 20, 2012


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