Most popular questions and responses by christina
  1. Chemistry

    What is the ionic and net ionic equation for Na2CO3 + 2 HNO3 -> 2 NaNO3 + H2O + CO2 (g) This is what i have so far... Na2(aq)+CO3+H+NO3 -> Na+ NO3+ H2O(l)+CO2(g)... i don't know what to do!!!

    asked on November 3, 2009
  2. Calculus

    Suppose f(pi/3) = 3 and f '(pi/3) = −7, and let g(x) = f(x) sin x and h(x) = (cos x)/f(x). Find the following. a. g'(pi/3) b. h'(pi/3)

    asked on November 7, 2011
  3. Algebra

    The back of Tom's property is a creek. Tom would like to enclose a rectangular area, using the creek as one side and fencing for the other three sides, to create a corral. If there is 100 feet of fencing available, what is the maximum possible area of the

    asked on October 5, 2015
  4. Social Studies

    1. Diversity most closely means (1 point) sharing cultural traits and practices with others. making up a whole of many different parts. being a member of a small ethnic group. having many similar regions next to one another. 2. How does life in Istanbul

    asked on December 10, 2013
  5. AP Chemistry

    CH3NH2(aq)+H2O(l)=>CH3NH3+(aq)+OH-(aq) Kb=4.4 x 10^-4 Methylamine, CH3NH2, is a weak base that reacts with water according to the equation above. A student obtains a 50.0 mL sample of a methylamine solution and determines the pH of the solution to be

    asked on May 2, 2013
  6. Calculus

    The number N of US cellular phone subscribers (in millions) is shown in the table. (Midyear estimates are given.) t 1996 1998 2000 2002 2004 2006 N 44 69 109 141 182 233 (a) Find the average rate of cell phone growth between the following years. In each

    asked on October 29, 2011
  7. physics

    Find the linear speed of the bottom of a test tube in a centrifuge if the centripetal acceleration there is 5.5×104 times the acceleration of gravity. The distance from the axis of rotation to the bottom of the test tube is 8.0 .

    asked on March 25, 2011
  8. Chemistry

    The percent composition by mass of an unknown compound with a molecular mass of 60.052 amu is 40.002% C, 6.7135% H, and 53.284% O. Determine the compound's empirical and molecular formulas.

    asked on October 10, 2017
  9. science (chem)

    For the preparation and standardization of NaOH with KHP im supposed to boil water for 1hr and 30 min to remove CO2....the problem is that if I don't boil it for that long and (30 min) b/c of not enough time but I put the water I boiled for 1/2 hr

    asked on June 22, 2007
  10. Physics

    A 0.5 kg wooden block is dropped from a height of 15 m. At what height must a 5g bullet be traveling upward strike the block in order to momentarily stop its fall? Assume that the time required for the bullet to come to rest in the block in negligibly

    asked on January 22, 2014
  11. Physics

    Suppose we take a 1 m long uniform bar and support it at the 27 cm mark. Hanging a 0.31 kg mass on the short end of the beam results in the system being in balance. Find the mass of the beam.

    asked on March 28, 2014
  12. Geography

    What role did the waterways of Europe play in the development of it's economy?

    asked on January 21, 2015
  13. geography

    compare latin america's landmass and population to those of the united states. Based on that data, how might the overall population densities of the two compare?

    asked on January 25, 2010
  14. Chemistry

    You have a solution of 0.500 M NaCl. If you add an equal amount of water to this solution, doubling the volume, what is the concentration of this solution?

    asked on October 15, 2017
  15. Physics

    A small block on a frictionless horizontal surface has a mass of 2.50×10−2 Kg. It is attached to a massless cord passing through a hole in the surface. The block is originally revolving at a distance of 0.300 m from the hole with an angular speed of

    asked on November 7, 2007
  16. Chemistry

    A 2.52g sample of a compound containing only carbon, hydrogen, nitrogen, oxygen, and sulfur was burned in excess O to yield 4.36g of CO2 and 0.892g of H20. Another sample of the same compound of mass 4.14g, yielded g of SO3. A third sample, of mass, 5.66g,

    asked on September 6, 2010
  17. physics

    An automobile tire is rated to last for 45,000 miles. Estimate the number of revolutions the tire will make in its lifetime.

    asked on January 13, 2011
  18. Physics

    A CD rotates at 500 (revolutions per minute) while the last song is playing, and then spins down to zero angular speed in 2.60 seconds with constant angular acceleration. The magnitude of the angular acceleration of the CD, as it spins to a stop is 20.1

    asked on November 3, 2007
  19. math

    At Strawberry State College, the ratio of females to males is 2:1. If there are 2100 students, how many are female and how many are male?

    asked on November 16, 2012
  20. College Chemistry

    Suppose there are two known compounds containing the generic elements X and Y. You have a 1.00-g sample of each compound. One sample contains 0.29 g of X and the other contains 0.38 g of X. Identify plausible sets of formulas for these two compounds. Check

    asked on September 3, 2014
  21. history

    What is the relationship between the ruling class and warrior class in Japan and Europe? I know that in Japan the Samurais were the warrior and ruling class till the Edo period right? but what about Europe?

    asked on November 19, 2008
  22. Physics -Interference & Diffraction

    Given Information: Light of wavelength 631 nm passes through a diffraction grating having 485 lines/mm. Part A: What is the total number of bright spots (indicating complete constructive interference) that will occur on a large distant screen? *Answer: 7

    asked on April 11, 2008
  23. science( chem)

    For the lab of Determining the % of iron in an iron ore sample The instructions were to: 1) Weigh out btw 0.3-0.4g of iron ore 2) disolve in concent HCl (10ml) and 3ml of 0.25M SnCl2 3) add enough tin so the yellow color disapeared 4) heat until sample

    asked on July 17, 2007
  24. math

    a steel cargo container is shaped like a cube measuring 5.2ft on each edge. How much steel is needed to make this container?

    asked on August 12, 2011
  25. geometry

    a spherical water storage tank has a radius of 10ft. A cubic foot of water is about 7.5 gallons. How many gallons of water will the tank hold?

    asked on August 10, 2011
  26. Ap physics B

    Four positive charges are fixed at the corners of a square, as shown above. Three of the charges have magnitude Q, and the fourth charge has a magnitude 2Q. Point P is at the center of the square at a distance r from each charge. 22. What is the electric

    asked on May 15, 2011
  27. Physics

    Calculate the specific heat of a metallic element if 314 joules of energy are needed to raise a 50.0 g sample from 25 to 50 degress C ? :)

    asked on March 21, 2010
  28. science( chem)

    When 100.0ml of a weak acid was titrated with 0.09381M NaOH, 27.63ml were required to reach the equivalence point. The pH at the equivalence point was 10.99. What was the pH when only 19.47ml of NaOH had been added ? I'll just post my work and I need

    asked on July 22, 2007
  29. Chemistry

    Rank the following in order of increasing bond polarity: H-F, H-Br, F-F, Na-Cl. Is it this....? F-F, H-Br, H-F, Na-Cl

    asked on November 22, 2015
  30. chemistry

    given the reactant amounts specified in each chemical eguation, determine the limiting reactant in each case: a. HCL+NaOH->NaCl+H2O 2.0 mole of HCl 2.5 mole NaOH b. Zn+2HCl->ZnCl2+H2 2.5 mole Zn 6.o mole HCl c. 2Fe(OH)3+3H2SO4->Fe2(SO4)3+6H2O 4.0 mole

    asked on March 3, 2010
  31. Finance

    Ngata Corp. issued 12-year bonds 2 years ago at a coupon rate of 8.4 percent. The bonds make semiannual payments. If these bonds currently sell for 105 percent of par value, the YTM is ? percent

    asked on July 23, 2010
  32. math

    Maude uses 3/4 of her allowance to get a massage for 3/5 of an hour. What fraxction of her allowance would she need to get a massage for a full hour?

    asked on March 19, 2018
  33. science

    You measure the dimensions of a rectangular block of aluminum to determine its volume. It has the following dimensions. length = 10.27 cm; width = 4.92 cm; height = 1.53 cm Assuming that each of these measurements is accurate to the nearest 0.01 cm, find

    asked on February 3, 2014
  34. science(chem)

    What is Zimmerman Reagent made of? (I know it is acidic b/c I was told after it burned a hole in my jeans) acid? You must mean Zimmermann-Reinhardt reagent (79 g MnSO4, 100 mL of concentrated H2SO4, and 200 mL of concentrated H3PO4, diluted to 1 L)

    asked on July 16, 2007
  35. Physics

    The Achilles tendon, which connects the calf muscles to the heel, is the thickest and strongest tendon in the body. In extreme activities, such as sprinting, it can be subjected to forces as high as 13.0 times a person's weight. According to one set of

    asked on November 13, 2007
  36. science (chem)

    what is the chemical eqzn of Na2CO3 + HClO4? Na2CO3 + HClO4 ==> NaClO4 + H2O + CO2 I will leave it for you to balance. how did you get that DrBob The rule on carbonates is: An acid added to a carbonate yields carbon dioxide, water, and a salt. oooh so you

    asked on June 24, 2007
  37. Physics

    A test rocket is launched by accelerating it along a 200.0-m incline at 1.25m/s2 starting from rest at point A (the figure (Figure 1) .) The incline rises at 35.0 ∘ above the horizontal, and at the instant the rocket leaves it, its engines turn off and

    asked on February 1, 2014
  38. math

    Alex came home after school one day and found that his mother had left a plate of cookies. Alex ate 1/4 of the cookies. When his sister Bernice came home, she ate 1/3 of the remaining cookies, and when Carla came home, she ate 1/2 of the cookies on the

    asked on October 31, 2012
  39. statistics

    Use the random-number table to simulate the outcomes of tossing a quarter 25 times. Assume that the quarter is balanced (i.e., fair). (Start at row 1, and let 0, 1, 2, 3, 4 indicate heads and 5, 6, 7, 8, 9 indicate tails. Enter H for heads and T for tails,

    asked on August 24, 2010
  40. Science

    The sensitivity of a measuring instrument is the value of the smallest quantity that can be read or estimated with it. What is the smallest part of a centimeter that can be read with the following? (a) a meterstick with markings at each millimeter I tried

    asked on February 3, 2014
  41. geometry

    how many milliliters of soup will this hemispherical bowl hold?(1cm cubed holds 1mL) Radius= 7 cm

    asked on August 12, 2011
  42. math

    Jacob opens a savings account on January 1 with a deposit of $350. He has "direct deposit," in which $25 is deposited every other week. The bank also charges a $3 monthly processing fee. How much money will he have at the end of the year?

    asked on October 31, 2012
  43. Calculus

    The area A of the region S that lies under the graph of the continuous function is the limit of the sum of the areas of approximating rectangles. A = lim n → ∞ [f(x1)Δx + f(x2)Δx + . . . + f(xn)Δx] Use this definition to find an expression for the

    asked on November 24, 2013
  44. Statistics

    A random sample of 100 cable TV movies contained an average of 3.38 acts of physical violence per program. At the 99% level what is your estimate of the population value? mean = 3.38 s = 0.30 N = 100

    asked on June 14, 2015
  45. Business English

    Write a paragraph describing your attitudes toward writing. Use the following steps. Prewrite: Jot down a few of the words that come to mind when you think of writing. Think of any significant experiences you have had that have shaped your attitude toward

    asked on January 23, 2019
  46. math

    a peanut butter jar has a height of 5.9in and diameter of 3.6 in. one cubic inch holds 0.45 oz of peanut butter. How many ounces will fit in the jar

    asked on August 12, 2011
  47. Chemistry

    The Cu2+ ion can be separated from Ag+, Ca2+, and K+ in aqueous solution by 1. precipitation of Cu2+ as Cu(OH)2(s) with 6 M NaOH(aq). 2. precipitation of Ag+, Ca2+, and K+ as the carbonates. 3. None of these procedures will separate Cu2+ from the other

    asked on April 5, 2010
  48. Chemistry

    Chlorine gas may be easily prepared in the lab according to the reaction: 2KMnO4(s)+ 16HCl(aq)-> 2 MnCl2(aq)+5Cl2(g)+ 8H2O(l)+ 2KCl(aq) What mass of HCl is needed to prepare 1 mole of Cl2 gas?

    asked on November 1, 2009
  49. Algebra

    Find the linear function with the following properties: f(0)=1 and the slope of f equals -3/2 THANK YOU

    asked on October 10, 2015
  50. Physics

    A boat is being towed through a canal by means of ropes which make a 45 degree angle to each other. If a force of 75N is applied to the rope, what is the resultant force pulling the boat forward?

    asked on November 3, 2013
  51. Chemistry

    If 20 grams of sulfur reacts with an excess of oxygen, what volume of the product SO2 would be collected at 108.5 kPa and 15 degrees Celseius?

    asked on April 30, 2013
  52. physics

    Suppose the spring in this spring-powered rifle has a spring constant of k = 1,000 N/m. How much work can it do in accelerating the projectile, if it is compressed by x = 0.10 m?

    asked on March 16, 2012
  53. chemistry

    The mineral CaF2 has a solubility of 2.1 x 10^-4 M. What is the Ksp of CaF2? a. 1.85x10^-11 b. 9.3x10^-12 c. 3.7x10^-11 d. 8.8x10^-3

    asked on January 4, 2010
  54. math

    A child has a large supply of dominoes, each of which measures 16 millimeters by 88 millimeters. She wants to lay them out to form a solid square, and she wants them all to be laid out horizontally. What will be the dimensions of the smallest square that

    asked on October 26, 2012
  55. math bus 105

    Calculate (a) interest and maturity value, (b) discount period, (c) bank discount, and (d) proceeds. Assume ordinary interest. (Round answers to nearest hundredths) Date of note Face value Length of note Interest rate Bank discount rate Date of discount

    asked on October 30, 2016
  56. Geography

    Which of the following most accurately describes the difference between climate and weather? (1 point) Climate refers to long-terms conditions; weather refers to daily conditions. Climate refers to severe weather events; weather refers to precipitation.

    asked on August 25, 2014
  57. Physics

    A stuntman sitting on a tree limb wishes to drop vertically onto a horse galloping under the tree. The constant speed of the horse is 10.0 m/s, and the man is initially 2.75 m above the level of the saddle. (a) What must be the horizontal distance between

    asked on February 7, 2012
  58. Physics-help please!

    You decide to use your body as a Carnot heat engine. The operating gas is in a tube with one end in your mouth (where the temperature is 37.0 C) and the other end at the surface of your skin, at 30.0 C. What is the maximum efficiency of such a heat engine?

    asked on December 15, 2007
  59. Physics -I'm stumped

    Europa, a satellite of Jupiter, appears to have an ocean beneath its icy surface. Proposals have been made to send a robotic submarine to Europa to see if there might be life there. There is no atmosphere on Europa, and we shall assume that the surface ice

    asked on November 30, 2007
  60. math

    a # that is neither prime nor the sum of two distinct primes. are you doing that month of math thing?

    asked on October 25, 2006
  61. chemistry

    Suppose that the microwave radiation has a wavelength of 12 cm . How many photons are required to heat 255 mL of coffee from 25.0 ∘C to 62.0 ∘C? Assume that the coffee has the same density, 0.997 g/mL , and specific heat capacity, 4.184 J/(g⋅K) , as

    asked on March 14, 2016
  62. Physics

    A test rocket is launched by accelerating it along a 200.0-m incline at 1.25m/s2 starting from rest at point A (the figure (Figure 1) .) The incline rises at 35.0 ∘ above the horizontal, and at the instant the rocket leaves it, its engines turn off and

    asked on February 2, 2014
  63. Chemistry

    Given the Empirical formula: C6H7N, and a molecular mass of 372.52 g/mol, How do I find the MOLECULAR formula for the compound?

    asked on September 18, 2011
  64. math

    The GCF of two numbers is 15. Their LCM is 450. What are the two numbers? (Enter your answers as a comma-separated list.)

    asked on October 26, 2012
  65. chemistry

    A lab tech had accidentally set out 16M HCl for this experiment. How much ( in mL) 16M HCl is needed to make 450mL of a 3M HCl solution?

    asked on October 7, 2013
  66. geometry

    jo was comparing two cylinders that both had a radius of 5cm. the first had a height of 10cm, and the other a height of 20cm. How many times greater was the volume of the larger cylinder?

    asked on August 12, 2011
  67. science-gen chem

    if 0.969 g of CaCl2 is mixed with 1.111 g of KlO3 how many grams of solid Ca(IO3)2 can theoretically be made? CaCl2(aq) + 2KlO3(aq) ===> 2Kcl(aq) + Ca(lO3)2 (s)

    asked on October 27, 2014
  68. general science

    if an object is thrown 60 m into the air and it takes the object 6 s to get there, what's the average speed of the object? (A) 20m/s (B) 360 m/s (C) 100 m/s (D) 10 m/s

    asked on May 5, 2014
  69. Physics

    To strengthen his arm and chest muscles, an 83.0 kg athlete 2.00 m tall is doing a series of push-ups. His center of mass is 1.15 m from the bottom of his feet, and the centers of his palms are 30.0 cm from the top of his head. Find the force that the

    asked on November 5, 2007
  70. Statistics

    you create the data create a set of seven numbers (repeats allowed) that have the five numbers summary. minimum =4 Q1=8 M=12 Q3=15 Maximum=19. There is more than one set of seven numbers with this five number summary. What must be true about the seven

    asked on February 3, 2019
  71. stats.

    The GMAT test is required for admission to most graduate programs in business. In a recent year, the GMAT test scores were normally distributed with a mean of 550 and standard deviation of 100. A. Find the first quartile for the distribution of GMAT

    asked on March 18, 2013
  72. science/math

    A car traveling at the speed of 30.0 m/sec encounters an emergency and comes to a complete stop. how much time will it take for the car to stop if its rate of deceleration is -4.0 m/sec

    asked on January 16, 2014
  73. Chemistry

    A sealed flask contains 1 mole of hydrogen and 3 moles of helium gas at 20DC. If the total pressure is 40kPa, what is the partial pressure of the Hydrogen gas? AND :) The data below was obtained by a student in order to determine the percent of water in a

    asked on March 31, 2013
  74. Physics

    The outstretched hands and arms of a figure skater preparing for a spin can be considered a slender rod pivoting about an axis through its center. When the skater's hands and arms are brought in and wrapped around his body to execute the spin, the hands

    asked on November 7, 2007
  75. physics

    Two mirrors are placed at a 90° angle to each other. A light ray strikes one mirror 0.730 m from the intersection of the mirrors with an incident angle of 36.5°. The ray then travels a distance d before reflecting from the second mirror. (a) What is the

    asked on May 12, 2014
  76. chemistry

    A STUDENT STUDYING THE FE+3- HSCN equilibrium put into a test tube 10.00ml of 2.00 x 10-3 M Fe(NO3)3 with 10.0 mL of 2.00 x 10-3 M HSCN.THE H+ in the resulting solution was manteined at 0.500.By spectrophotometric analysis of the equilibrium solution, the

    asked on September 29, 2012
  77. Finance

    You have found the following stock quote for RJW Enterprises, Inc., in the financial pages of today's newspaper. The closing price for this stock that appeared in yesterday's paper was $ (Do not include the dollar sign ($). Round your answer to 2 decimal

    asked on July 30, 2010
  78. Chemistry

    Some drain cleaners contain a mixture of sodium hydroxide and aluminum which reacts with water as follows: 2Al(s)+2 NaOH(aq)+6H2O(l)->2Na[Al(OH)4](aq)+3H2(g) What mass of hydrogen gas can be produced when 5g Al reacts with sufficient NaOH and H2O)

    asked on November 1, 2009
  79. Physics

    Oxygen (O2) has a molar mass of 32.0 g/mol [.032kg/mol]. What is the root-mean-square speed of an oxygen molecule at a temperature of 310 K? Vrms=492 m/s What is its average translational kinetic energy at that speed? Kav= ?? J I am having problems with

    asked on December 9, 2007
  80. math final review (help)

    from a 12cm by 12cm piece of cardboard, square corners are cut out so that the sides can be folded up to make a box. Express the volume of the box as a function of the length, x, in centimeters.

    asked on December 16, 2012
  81. Chemistry

    What would happen to the color of a dilute solution containing FeCL4 if you added concentrated HCl?

    asked on April 26, 2010
  82. physics

    A typical ten-pound car wheel has a moment of inertia of about . The wheel rotates about the axle at a constant angular speed making 30.0 full revolutions in a time interval of 5.00 .

    asked on December 6, 2009
  83. Chemistry

    Calculate the boiling point elevation of a solution made from 15.0 g of a nonelectrolyte solute and 250.0 g of water. the molar mass of the solute is 50.0 g and Kb = 0.51 degrees C/m

    asked on June 7, 2010
  84. Chemistry

    How many liters of hydrogen at STP can be produced by the reaction of 4.15 g of zinc with hydrochloric acid: Zn + 2HCl -> ZnCl2 + H2

    asked on November 9, 2009
  85. science( chem)

    Calculate the molar solubility of Mg(OH)2 in water I know Mg(OH)2=> Mg2+ + 2OH- 2H2O=> H3O+ + OH- Ksp= [Mg2+][OH]2 Kw= [H30+][OH-] Mass balance [Mg2+]=2[OH] So.. [OH-]=2[Mg2+]+ [H3O+] Charge balance is where I get kind of confused I know that the positive

    asked on July 20, 2007
  86. Math URGENT!!

    The speed of a runner increased steadily during the first three seconds of a race. Her speed at half-second intervals is given in the table. Find a lower estimate for the distance that she traveled during these three seconds. t(s) 0 0.5 1.0 1.5 2.0 2.5 3.0

    asked on April 14, 2007
  87. calculus

    Find the limit. Use l'Hospital's Rule if appropriate. If there is a more elementary method, consider using it. lim x→∞ {(5x − 4)/(5x + 3)}^5x + 1

    asked on March 17, 2017
  88. physics

    dahnay carried a box (5,4)m.the box had a mass of 5kg.dahnay says that over 300J of work was done on the box . is dahnay correct?explain the answer.

    asked on March 16, 2015
  89. algebra

    You deposit $3000 in an account earning 7% interest compounded continuously. The amount of money in the account after years is given by A(t)=3000 e^(0.07 t) . How much will you have in the account in 5 years? $ Round your answer to 2 decimal places. How

    asked on November 22, 2014
  90. Chemistry

    Calculate the amount of heat (in calories) required to raise the temperature of 200g of water from 20C to 50C. The specific heat of water is 1.00 cal/g. I have done other spacific heat problems but on this one i don't know how to start...

    asked on November 10, 2009
  91. college

    Electro-Rad Inc., a developer of radiology equipment, has stock outstanding as follows: 50,000 shares of 2%, preferred stock of $50 par, and 100,000 shares of $25 par common. During its first four years of operations, the following amounts were distributed

    asked on September 24, 2009
  92. Chemistry

    At a given Temperature, the elementary reaction AB in the forward direction is first order in A with a rate constant of 3.90*10^-2s^-1. The reverse reaction is first order in B and the rate constant is 8.20*10^-2s^-1. What is the value at equillibrium for

    asked on March 18, 2013
  93. chemistry

    Calcium carbonate reacts with hydrochloric acid according to the following reaction: CaCO3 (s) + 2 HCl (aq) --> CaCl2 (aq) + H2O (l) + CO2 (g) How many grams of calcium carbonate would be required to neutralize 50.0 cm3 of 8.00 M HCl?

    asked on November 7, 2010
  94. geometry

    An airplane over the pacific sights an atoll at 8 degree angle of depression. If the plane is 520hm above water, how many kilometers is it from a point 520 m directly above the center of the atoll? Help please :]

    asked on April 4, 2011
  95. college

    If a single bacteria divides in half every 20 min. how many would you have after 42 hours?

    asked on February 6, 2010
  96. Chemistry

    When 24.0 cal of heat is added to 18.5 g of aluminum at 19.0 ∘C, what is the final temperature of the aluminum?

    asked on September 14, 2015
  97. Geography

    Which of the following are impacts that the temperate climate has had on Georgia’s development? (1 point) encouraging crops with longer growing seasons drawing immigrants from other locations encouraging tourism all of the above 3. What impacts have

    asked on August 25, 2014
  98. AP European History

    How did Medieval Europe lay the groundwork for the re-birth of Europe (Renaissance)? What conditions existed that allowed Europe to evolve out of medieval conditions? I don't even know where to start, other than that I know that monarchs began to solidify

    asked on February 11, 2011
  99. physics

    A light rope is attached to a block with a mass of 6 kg that rests on a horizontal, frictionless surface. THe horizontal rope passes over a frictionless, massless pulley, and a block of mass m is suspended from the other end. When the blocks are released,

    asked on November 16, 2006
  100. Sociology

    Discuss the conclusions of Margaret Mead concerning temperament, and explain how she arrived at her conclusions.

    asked on September 27, 2012


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