Most popular questions and responses by kelly
  1. chemistry

    Complete and balance the molecular equation, including phases, for the reaction of aqueous ammonium bromide, NH4Br, and aqueous lead(II) acetate, Pb(C2H3O2). Enter the balanced net ionic equation, including phases, for this reaction.

    asked on October 23, 2012
  2. College Chemistry

    I balanced the equation: HBr(aq) +NH3(aq)->NH4Br I need to find the ionic equation and the net ionic equation

    asked on October 3, 2010
  3. Math

    Find the unit rate. Round to the nearest tenth, if necessary. 344 miles in 11 hours 344 3,784 0.03 31.27 ** Find the unit rate. In 10 months, 62.6 gallons were used. 0.16 10 6.26 ** 626

    asked on December 1, 2016
  4. math

    For his exercise today, Josh plans to both run and swim. Let r be the number of laps he runs and let s be the number of laps he swims. Each lap he runs takes him 4 minutes, and each lap he swims takes him 3 minutes. He wants to exercise for at least 30

    asked on September 25, 2016
  5. Chemistry

    Write chemical formulas for the compounds formed by the following positive and negative ions: Ba2+ and NO3-, Al3+ and Co3, and K+ and PO43-

    asked on July 30, 2016
  6. Language Arts

    What is the most important element of the plot of Lord of the Rings? a) the elves sailing away on ships b) Galadriel's gifts of magic c) the journey to destroy the ring or d) the journey to Rivendell. I think it is C) the journey to destroy the ring.

    asked on August 18, 2015
  7. chemistry

    Will sodium sulfide and iron II sulfate form a precipitate? if so what would the reaction look like?

    asked on December 12, 2010
  8. Math

    My son's math homework asks him to find each product by factoring the tens. 6 x 2, 6 x 20 and 60 x 20. There is no explaination in the book..can you help?

    asked on January 4, 2011
  9. Are All Right? Math

    Use cross products to see if each pair of ratios forms a proportion. Replace each box with = or ≠. 1. 7/5 ? 15/10 = ≠

    asked on December 1, 2016
  10. English

    Which of the following did NOT contribute to the Harlem Renaissance? A.The Emancipation Proclamation. B. By 1930, the population of African Americans in Harlem grew to over 200,000.

    asked on February 26, 2016
  11. Chemistry

    Write the net ionic equation for the precipitation reaction between ammonium sulfide and cadmium nitrate.

    asked on June 7, 2010
  12. Physics

    A boy on a bucycle drags a wagon full of newspapers at 0.80m/s for 30 minutes using a force of 40N. How much work has the boy done?

    asked on April 8, 2011
  13. physics

    what is the final temperature when a 3.0 kg gold bar at 99 degrees is dropped into a .22 kg of water at 25 degrees

    asked on February 5, 2008
  14. 3rd grade math hw help!

    hello all, my daughter come home with a math homework "Alphabet Polygons" I have no idea how to use the letters in the alphabet to answer the questions. Please HELP! The questions are as follow: 1) You can make polygons of some of the letters by drawing

    asked on January 31, 2011
  15. Chemistry

    Consider the chemical equation. 2H2 + O2 -> 2H2O What is the percent yield of H2O if 87.0 g of H2O is produced by combining 95.0 g of O2 and 11.0 g of H2? a 56.5% b 59.0% c 88.5% d 99.7%

    asked on March 23, 2016
  16. Redox Reaction

    In an acidic solution, manganese(II) ion is oxidized to permanganate ion by bismuthate ion, BiO3-. In the reaction, BiO3- is reduced to Bi3+. How many milligrams of NaBiO3 are needed to oxidize the manganese in 30.2 mg of manganese(II) sulfate?

    asked on April 19, 2015
  17. Chemistry

    Two competing corporations are submitting data to the US Military to create chemical hot packs. The Military has stipulated that each hot pack may cost no more than 85 cents and must result in at least a 20degrees Celsius rise in temperature when

    asked on December 3, 2013
  18. physics

    A 1500kg car is approaching the hill shown in the figure at 15.0 m/s when it suddenly runs out of gas. Part A What is the car's speed after coasting down the other side?

    asked on November 26, 2012
  19. Calculus Practice Problems

    A filter filled with liquid is in the shape of a vertex-down cone with a height of 12 inches and a diameter of 18 inches at its open (upper) end. If the liquid drips out the bottom of the filter at the constant rate of 3 cubic inches per second, how fast

    asked on October 16, 2013
  20. chemistry

    how would you prepare 1.00 L of 0.50 M solution of NiCl2 from the salt nicl2·6H2O? thanks :)

    asked on August 24, 2010
  21. chemistry

    Find the concentration of Cu+ in equilibrium with CuBr(s) and 0.10 M Br-.

    asked on September 11, 2011
  22. Math

    Hi can someone please help me? A recent study gave the information shown in the table about ages of children receiving toys. The percentages represent all toys sold. Age (years) Percentage of Toys 2 and under 3-5 6-9 10-12 13 and over 17% 19% 24% 13% 27%

    asked on December 14, 2016
  23. Chemistry

    Gasoline is primarily a mixture of hydrocarbons and is sold with an octane rating that is based on a comparison with the combustion properties of isooctane. Gasoline usually contains an isomer of isooctane called tetramethylbutane (C8H18), which has an

    asked on July 9, 2013
  24. Chemistry

    If 0.48 g of sulfur are added to 200 g of carbon tetracholoride, and the freezing point of the carbon tetrachloride (Kf=30 degrees C/m) is depressed by 0.28 degrees C, what is the molar mass and molecular formula of the sulfur? .48g * 1mol/32.07g= .01497

    asked on February 17, 2012
  25. College Chemistry-Please help me

    I need to find the ionic equation of: 3Ba(OH)2(aq)+2H3PO4(aq)->Ba3(PO4)2+6H20(l) I'm totally lost on this question

    asked on October 4, 2010
  26. Calculus

    If a rock is thrown upward on the planet Mars with a velocity of 19 m/s, its height (in meters) after t seconds is given by H = 19t − 1.86t^2. When will the rock hit the surface?

    asked on September 14, 2015
  27. Math

    Alicia has a flat platter shaped like a square with a semicircle of diameter 10 inches on each edge, as pictured. What is the number of inches in the side length of the smallest square ABCD that can contain the platter? I drew a diagram so far, but I don't

    asked on March 22, 2015
  28. Algebra

    Joylin receives a $50 gift card for the local movie theater for her birthday. She uses the card to purchase tickets and snacks for her family. If Joylin spends $6 more on tickets than she does on snacks, how much does Joylin spend on tickets?

    asked on July 3, 2014
  29. Chemistry

    40.0 ml of an acetic acid of unknown concentration is titrated with 0.100 M NaOH. After 20.0 mL of the base solution has been added, the pH in the titration flask is 5.10. What was the concentration of the original acetic acid solution? [Ka(CH3COOH) = 1.8

    asked on November 9, 2010
  30. Calculus Homework

    You are blowing air into a spherical balloon at a rate of 7 cubic inches per second. The goal of this problem is to answer the following question: What is the rate of change of the surface area of the balloon at time t= 1 second, given that the balloon has

    asked on October 16, 2013
  31. college chem

    Two questions where I have to write a balanced net ionic equation. 1. Write a balanced net ionic equation for the reaction that occurs when aqueous solutions of sodium chromate and silver nitrate are mixed 2. Write a balanced net ionic equaion reaction for

    asked on June 2, 2009
  32. Chemistry

    Write the equation for the dissolution of (NH4)2S04 in water. How many moles of each type of ion, and how many total moles of ions does the dissolution of 0.5 mol of (NH4)2S04 produce? help pleaseeeeee ASAP

    asked on April 6, 2011
  33. physics

    An automobile traveling 95 overtakes a 1.10--long train traveling in the same direction on a track parallel to the road. Q1: If the train's speed is 75 , how long does it take the car to pass it Q2:How far will the car have traveled in this time? Q3:What

    asked on April 8, 2012
  34. Chemistry

    Ethane (C2H6) reacts with oxygen to produce carbon dioxide and water. Assuming there is an excess of oxygen, calculate the mass of CO2 and H2O produced from 1.25 g of ethane

    asked on January 11, 2012
  35. Chemistry

    What will be the final temperature if 2000g of copper at 95 degrees loses 10 kcal of heat?

    asked on October 15, 2010
  36. Physics

    A watermelon seed has the following coordinates: x = -8.7 m, y = 1.6 m, and z = 0 m. Find its position vector as (a) a magnitude and (b) an angle relative to the positive direction of the x axis. If the seed is moved to the xyz coordinates ( 3.4 m, 0 m, 0

    asked on February 2, 2015
  37. physics

    Two point charges are fixed on the y axis: a negative point charge q1 = -23 µC at y1 = +0.23 m and a positive point charge q2 at y2 = +0.33 m. A third point charge q = +7.8 µC is fixed at the origin. The net electrostatic force exerted on the charge q by

    asked on March 29, 2012
  38. Biology*STUCK*

    A group of students was asked to list some of the similarities and differences between prokaryotic cells and eukaryotic cells. They created the table shown above. The students made a mistake in creating their table. Which statement best describes their

    asked on November 20, 2014
  39. Science

    Which chemical equation shows that no atoms are lost during a chemical reaction? A. 8Fe+s8-->Fe5 B. 8Fe+8S8--> 8FeS C. Fe+8S8--->FeS D. 8Fe+S8--->8FeS Is the answer A?

    asked on April 16, 2015
  40. physics

    The amplitude of an oscillator decreases to 69.0% of its initial value in 15.5s. a) What is the value of the time constant?

    asked on December 1, 2009
  41. college chemistry

    How many total moles of ions are released when the following sample dissolves completely in water: 5.15x10^-3 g Ca(NO3)2

    asked on September 26, 2010
  42. Chemistry

    Acetylene(C2H2) torches are used in welding. How much heat (in kJ) evolves when 2.0L of C2H2 (d=1.0967kg/m3) is mixed with a stoichiometric amount of oxygen gas? The combustion reaction is C2H2(g)+52O2(g)→2CO2(g)+H2O(l), ΔH∘=−1299.5kJ

    asked on March 24, 2014
  43. Calculus

    The equation of motion of a particle is s = t3 − 12t, where s is in meters and t is in seconds. For the velocity function, I got v(t)=3t^2-12 and for acceleration, a(t)=6t. The final question is: Find the acceleration when the velocity is 0. How do I do

    asked on September 29, 2015
  44. Physics

    A 17.0 kg monkey hangs from a cord suspended from the ceiling of an elevator. The cord can withstand a tension of 220N and breaks as the elevator accelerates. What was the elevator's minimum acceleration (magnintude and direction)? Please show me how to do

    asked on January 2, 2007
  45. physics

    a block with a velocity 4m/s slides 8m across a rough horizontal floor before coming to rest.the coefficient of friction is.

    asked on January 27, 2014
  46. Physics

    A 50.0-kg student climbs a 5.00-m-long rope and stops at the top. (a) What must her average speed be in order to match the power output of a 200 W light bulb? (b) How much work does she do?

    asked on October 7, 2007
  47. Physics

    A stuntman is being pulled along a rough road at a constant velocity by a cable attached to a moving truck. The cable is parallel to the ground. The mass of the stuntman is 110 kg, and the coefficient of kinetic friction between the road and him is 0.825.

    asked on March 20, 2013
  48. Statistics

    The Weight of a small Starbucks coffee is normally distributed random variable with a mean of 360 grams and a standard deviation of 9 grams. Find the weight that corresponds to each event. a. highest 10% b. highest 50% c. highest 5% D. highest 80% e.

    asked on April 11, 2014
  49. physics

    An ionized helium atom has a mass of 6.6*10^-27kg and a speed of 4.4*10^5 m/s. The atom moves perpendicular to a 0.75-T magnetic field on a circular path of radius 0.012m. Determine whether the charge of the ionized helium atom is +e or +2e. Can anyone

    asked on April 1, 2008
  50. Chemisty- Please help!

    What mass of a 0.66 molality ammonium nitrate (80.04g/mol) solution will contain 0.15 mol of solute?

    asked on July 9, 2013
  51. World Liturature

    Explain the significance of the title Quality by John Galsworthy

    asked on November 15, 2009
  52. Calculus

    A 15 ft ladder is leaning against a wall.If the top of the ladder slips down the wall at a rate of 5ft/s, how fast will the foot be moving away from the wall when the top is 9ft above the ground.

    asked on July 17, 2010
  53. Chemistry

    In the reaction C + O2 → CO2, 18 g of carbon react with oxygen to produce 72 g of carbon dioxide. What mass of oxygen would be needed in the reaction?

    asked on July 6, 2016
  54. Chemistry

    20.0 ml of 1.00 M formic acid are combined with 10.0 ml of 1.00 M sodium formate. Calculate the expected pH. Ka for formic acid is 1.77 x 10^-4

    asked on November 13, 2014
  55. Chem

    Calculate the mass of baking soda, NaHCO3, needed to neutralize 3.0mL of 3.0 M hydrochloric acid.

    asked on February 27, 2008
  56. physics

    a 1100 kg wrecking ball hangs from a16m long cable. the ball is pulled back until the cable makes an angle of 17 with the vertical. By how much has the gravitational potential energy of the ball changed?

    asked on November 26, 2012
  57. Chemistry

    The Ka values of H2CO3 are shown below. Ka1 4.6 10-7 Ka2 4.4 10-11 What is the pH of a 0.17 M solution of Na2CO3?

    asked on October 25, 2010
  58. chemistry

    3.0g of a mixture of potassium carbonate and potassium chloride were dissolved in a 250cm3 standard flask. 25cm3 of this solution required 40.00cm3 of 0.01M HCl for neutralization. What is the percentage by weight of K2CO3 in the mixture? (K = 39, O = 16,

    asked on June 28, 2018
  59. english

    Which of the following did NOT contribute to the Harlem Renaissance? A.The Emancipation Proclamation. B. By 1930, the population of African Americans in Harlem grew to over 200,000. C.F. Scott Fitzgerald

    asked on February 26, 2016
  60. physics

    A sensitive gravimeter at a mountian observatory finds that the free-fall acceleration is 6.00 X 10^3 m/s^2 less than that at sea level. What is the observatory's altitude?

    asked on December 1, 2009
  61. physics

    A firefighter of mass 120 kg slides down a vertical pole with an acceleration of 4 m/s per second. What is the friction force that acts on the firefighters? In this case, the friction force is the force that is acting against gravity. Use F=M*a If

    asked on September 20, 2006
  62. Math

    A rock is thrown upward with a velocity of 12 meters per sec from the top of a 25 meter high cliff and it misses on it's way back down. When will the rock be 3 meters from water

    asked on September 1, 2015
  63. physics

    Planet Z is 1.00×10^4 km in diameter. The free-fall acceleration on Planet Z is 10.0 m/s^2. a)What is the mass of Planet Z? b)What is the free-fall acceleration 9000 km above Planet Z's north pole?

    asked on December 1, 2009
  64. Chemistry

    Running at a rate of 6 mi/h uses 704 Calories in an hour. Convert this value to (a) calories; (b) kilocalories; (c) joules; (d) kilojoules.

    asked on October 25, 2012
  65. Chemistry

    the reaction of 6.62g of carbon with excess oxygen yields 13.40g of CO2. what is the percent yield of this reaction

    asked on May 18, 2013
  66. Physics

    The collision between a hammer and a nail can be considered to be approximately elastic. Estimate the kinetic energy acquired by a 13 g nail when it is struck by a 550 g hammer moving with an initial speed of 4.0 m/s. I solved for the final velocities of

    asked on April 27, 2010
  67. Chemistry

    A 100.00 ml of volume of 0.500 M HCl was mixed with 100.00 ml of 0.500 M KOH in a constant pressure calorimeter. The initial temperature of individual acid and base was 23.0 oC. The final temperature after mixing was 25.5 oC. The specific heat of the

    asked on March 5, 2018
  68. Calc

    The maker of an automobile advertises that it takes 13 seconds to accelerate from 25 kilometers per hour to 90 kilometers per hour. Assuming constant acceleration, compute the following. The acceleration in m/s^2 The distance the car travels during the 13

    asked on November 18, 2016
  69. Physics

    A student presses a book between his hands, as the drawing indicates. The forces that he exerts on the front and back covers of the book are perpendicular to the book and are horizontal. The book weighs 32 N. The coefficient of static friction between his

    asked on February 15, 2010
  70. calculus

    An airplane is flying on a bearing of 80 degrees at 540mph. A wind is blowing with a bearing of 100 degrees at 55mph. Find the component form of the velocity of the airplane.

    asked on February 7, 2010
  71. Physics

    Hunting a black hole. Observations of the light from a certain star indicate that it is part of a binary (two-star) system. This visible star has orbital speed v = 270 km/s, orbital period T = 1.6 days, and approximate mass m1 = 6.0Ms, where Ms is the

    asked on January 2, 2011
  72. English

    Each of the items below contains two of the types of verb mistakes discussed in this chapter. Find and cross out these two mistakes. Then, in the spaces provided, write the correct forms of the verbs. 1.

    asked on January 31, 2018
  73. chemistry

    how would you prepare 1.00 L of a .50M solution of H2SO4 from concentrated (18M) sulfric acid?

    asked on August 24, 2010
  74. Math

    The rotating light on a lighthouse is 400 feet from a cliff. It completes one rotation every 10 seconds. The equation representing the distance, d, in feet that the center of the circle of light is from the lighthouse is d(t) = 400sec (πt/5). What is the

    asked on October 3, 2014
  75. Physics

    Two students are on a balcony 19.6 m above the street. One student throws a ball (ball 1) vertically downward at 15.8 m/s; at the same instant, the other student throws a ball (ball 2) vertically upward at the same speed. The second ball just misses the

    asked on May 13, 2011
  76. Physics

    Michael Jordan, formerly of the Chicago Bulls basketball team, has some fanatic fans. They claim that he is able to jump and remain in the air for two full seconds from launch to landing. Evaluate this claim by calculating the maximum height that such a

    asked on October 11, 2010
  77. Chemistry

    If 0.48 g of sulfur are added to 200 g of carbon tetracholoride, and the freezing point of the carbon tetrachloride (Kf=30 degrees C/m) is depressed by 0.28 degrees C, what is the molar mass and molecular formula of the sulfur?

    asked on February 17, 2012
  78. Calculus Area between curves

    Consider the area between the graphs x+6y=8 and x+8=y2. This area can be computed in two different ways using integrals First of all it can be computed as a sum of two integrals where a= , b=, c= and f(x)= g(x)= I found a, but not b or c. I can't seem to

    asked on November 24, 2013
  79. Physics

    An object moves along the x axis, subject to the potential energy shown in Figure 8-24. The object has a mass of 1.8 kg, and starts at rest at point A. (a) What is the object's speeds at point B, at point C, and at point D?

    asked on March 31, 2010
  80. chemistry-check over work

    2C6H5Cl(chlorobenzene)+C2HOCl3(chloral)=C14H9Cl5(DDT)+H2O in a gov. lab 1142 g of chlorobenzene is reacted with 485 g of chloral. a). what mass of DDT is formed? 1166.179 g of C14H9Cl5 b). which reactant is limiting?C2HOCl3 which reactant is in

    asked on March 7, 2008
  81. Chemistry

    320g of sulfur dioxide react with 32.0g of oxygen and excess water to form sulfuric acid (H2SO4) a. What is the limiting reagent? b. What is the theoretical yield of product? c. How many grams of excess reagent will remain?

    asked on January 11, 2012
  82. chemistry

    The formula for epsom salt is MgSO4 . 7H20 If 1.250 g of the compound is dissolved in water, calculate the number of milliliters of .200 M Ba(NO3)2 that would be required to precipitate all of the sulfate ions as barium sulfate. I got that right with an

    asked on October 10, 2010
  83. Chem

    Solid carbon dioxide (dry ice) goes from solid to gas at -78C. The molar heat of sublimation is 25.3 kj/mol. In one experiment 34.5g of dry ice are placed in an insulated isolated container with 500 g of water at 25C. What temp of the water is expected

    asked on March 11, 2010
  84. college chem

    how many grams of NH4Cl are required to prepare 250 mL of .122 M NH4Cl solution? I set this up using the molarity equation and the part that I was missing is moles. So I divided the 0.122 by .25 L and got .031 mol. Then I took that and multiplied it by the

    asked on June 2, 2009
  85. Physics Thanks

    Please help... Let g be the acceleration due to gravity at the surface of a planet of radius R. Which of the following is a dimensionally correct formula for the minimum kinetic energy K that a projectile of mass m must have at the planet's surface if the

    asked on May 13, 2007
  86. Algebra 2

    a) The average height of sunflowers in a field is 64 inches with a standard deviation of 3.5 inches. Describe a normal curve for the distribution, including the values on the horizontal axis at one, two, and three standard deviations from the mean. b) If

    asked on April 23, 2013
  87. HUM

    I did not understand this part of my class so here is the question What is media convergence? Provide an example of media convergence and explain the media elements that are being combined. Explain how the combination of media elements in your example may

    asked on August 1, 2011
  88. English

    Writers often use language and images to foreshadow events that are going to take place in a story. Consider these words and phrases from the passage: dank tropical night moonless Caribbean night moist black velvet From these the reader can predict that

    asked on November 18, 2014
  89. Physics

    a mouse pushes a piece of cheese with a mass of 6.4 g for a distance of 75 cm over the frictionless surface of an air hockey table. He exerts a constant 0.5 N force as he does so. If the cheese starts from rest, what is it's final velocity?

    asked on December 5, 2012
  90. PHYSIC

    a solid aluminum ingot weighs 89N in air a)what is the volume b)the ingot is suspended from a rope and totally immersed in water. what is the tension in the rope(the apparent weight of the ingot in water)?

    asked on July 20, 2010
  91. Physics

    An object moves along the x axis, subject to the potential energy shown in Figure 8-24. The object has a mass of 1.8 kg, and starts at rest at point A. (a) What is the object's speeds at point B, at point C, and at point D?

    asked on March 31, 2010
  92. 2nd grade

    Why are the flat surfaces on a rectangular prism called faces?

    asked on December 9, 2010
  93. physics

    A rocket is launched straight up from the earth's surface at a speed of 1.80×104 m/s^2. a)What is its speed when it is very far away from the earth?

    asked on December 1, 2009
  94. social studies

    how did geograph contribute to ghana's wealth?

    asked on October 2, 2008
  95. college algebra

    The height of a projectile fired upward is given by the formula s = v0t – 16t2, where s is the height, v0 is the initial velocity and t is the time. Find the times at which a projectile with an initial velocity of 128 ft/s will be 144 ft above the

    asked on April 8, 2014
  96. College physics

    A skier traveling at 30.9 m/s encounters a 21.5 degree slope. If you could ignore friction, to the nearest meter, how far up the hill does he go?

    asked on June 16, 2012
  97. Physics

    A dog running in an open field has components of velocity vx = 3.0m/s and vy = -1.1m/s at time t1 = 11.7s . For the time interval from t1 = 11.7s to t2 = 22.2s , the average acceleration of the dog has magnitude 0.55m/s2 and direction 34.5∘ measured from

    asked on January 22, 2015
  98. chemistry

    For OCTANE, what is the ratio of Carbon atoms to Hydrogen atoms in a molecule? It's specified that Octane undergoes complete combustion to form 8L of Carbon Dioxide & 9L of Water at constant temp and pressure. thanks :)

    asked on September 24, 2010
  99. Chemistry

    a .6800g sample of carboxylic acid is burned in oxygen, producing 1.212 g of CO2 and .4991 g of H2O. determine the empirical formula of the carboxylic acid

    asked on May 18, 2013
  100. Math

    PQR ~ STU. PQ = 12cm and ST = 9cm. The area of STU is 72 cm². Find the area of PQR.

    asked on July 28, 2010


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