1. Analytical chemistry

    Below i wrote a few problems, i did them all but in the book i don't have results, so i don't know if i did them right or not. I would really appreciate if someone would go through the problems and tell me if i got the right results. If i made a mistake
  2. statistics

    4.The College Boards, which are administered each year to many thousands of high school students, are scored so as to yield a mean of 500 and standard deviation of 100. These scores are close to be normally distributed. a. What percentage of the scores can
  3. Business Statistics

    From past experience, an airline has found the luggage weight for individual air travelers on its trans- Atlantic route to have a mean of 80 pounds and a standard deviation of 20 pounds. The plane is consistently fully booked and holds 100 passengers. The
  4. classcal mechanics

    To a good approximation, the temperature T drops almost linearly with altitude up to 11 km above sea level, at a constant rate: dTdz=−α forz≤11 km where α=6.5 K/km (Kelvin per km) and z is the height above the sea level. The
  5. chemistry

    A copper wire weighing 5.463g was dissolved in excess nitric acid, precipitated as copper(2)carbonate with excess sodium carbonate, and then converted tooo copper(2) sulfate pentahydrate using excess sulfuric acid. A student carrying out these reactions
  6. Chemistry

    This is a back titration question and I'm struggling with it :/ So if you can help me, that would be very appreciated :) Q. A sample of steel wool was dissolved in excess sulfuric acid. The resulting solution (FeSO4 aq) was then titrated with potassium
  7. Microeconomics-Algebra Calculation

    Consider public policy aimed at smoking. Studies indicate that the price elasticity of demand for cigarettes in about 0.4. If a pack of cirarettes currently costs $2 and the government wants to reduce smoking by 20 percent, by how much should the govenment
  8. Math

    I am lost on this problem can someone help me with it? What is the major focal point of the story told by the information? Source of data: Ipsos-Public Affairs polls at least 966 people in each country September 17- October 2, 2005. Margin of error:
  9. Chemistry

    I need to determine the "percentage composition unknown" whatever that is. My current data: a) mass of test tube and foil cover: 7.5323 g b)temp of water bath: 375.65 K c) mass of test tube and foil and gas as sample: 7.5423 g d) barometric pressure:
  10. Math

    Students are given three chances to pass a basic skills exam for permission to enrol in Calculus. Sixty percent of the students pass on the first try, of those that fail on the first try, fifty four percent pass on the second try, and of those remaining,
  11. Math(Please Help Assignment Due Tomorrow)

    From the length(in seconds) of 80 randomly chosen U2 songs, the mean determined was 289.6986295 and standard deviation was 76.82292002. Assume that the data is normally distributed and that the bands entire collection of songs has a mean and standard
  12. sixth grade ratios and rates

    Tom and Jasper have the same percentage of blue marbles in their bags of marbles. tom has 5 blue marbles and 20 total marbles. Jasper has 12 blue marbles. How many of Jasper's marbles are not blue? I need help solving this problem.
  13. Math grade7

    Macy's is having a special on Tuesday .you can buy each tshirt at its regular price or you can buy tshirt for $ $ 25 Julie bought one of each tshirt at sale price of $ 25.00 what percentage of the original total rice did Julie save. Harry Julie's best
  14. MATH(Statistics)

    Students are given three chances to pass a basic skills exam for permission to enrol in Calculus. Sixty percent of the students pass on the first try, of those that fail on the first try, fifty four percent pass on the second try, and of those remaining,
  15. Environmental science

    I know how environmental science branches off to various sciences- how does astronomy (to be specific, the discovery that Pluto's not a planet anymore) relates to environmental science? Thank you! Reclassifying Pluto as "not a planet" is NOT a discovery.
  16. Average Body Fat

    What is the average body fat percentage?
  17. Chemistry

    Determine the number of grams of NH3 produced by the reaction of 3.5g of hydrogen gas with sufficient nitrogen gas 1. Write the balanced equation. 2. Convert what you have (3.5 g) into mols. Mols = grams/molar mass. 3. Use the coefficients in the balanced
  18. stats

    A company that manufactures and bottles apple juice has a machine that automatically fills 16-ounce bottles. There is some variation, however, in the exact amount of juice dispensed into each bottle. From a large number of observations taken over a long
  19. Mathematics question

    In my town some of the animals are really strange. Ten percent of the dogs think that they are cats and ten percent of the cats think they are dogs. All the other cats and dogs are perfectly normal. One day I tested all the cats and dogs in the town and
  20. chemistry

    The aspirin content in the analgesic tablets is determined from 120 samples to have a ean of 250 mg with a standard deviation of 5 mg. from a production line, what percentage of the tablets are expected to contain between 243 and 262 mg of aspirin?What is
  21. chemistry

    The aspirin content in the analgesic tablets is determined from 120 samples to have a ean of 250 mg with a standard deviation of 5 mg. from a production line, what percentage of the tablets are expected to contain between 243 and 262 mg of aspirin?What is
  22. statistics

    A sample distribution (closely approximating a normal distribution) of a critical part dimension has an average of 11.85 inches and a sample standard deviation of 1.33 inches. The lower specification limit is 11.41 inches. The upper specification limit is
  23. Physics

    (1) body is taken to depth of 32km below the surface of the earth. Calculate the percentage decrease in the weight of the body at this depth (The radius of the earth is 6400km) (2)A wire of mass per unit length 5.0gm-1 is stretched between 2 points 30cm
  24. Math (Statistics)

    How do I go about tackling this problem? The American Medical Association wishes to determine the percentage of obstetricians who are considering leaving the profession becaose of the rapidly increasing number of lawsuits against obstetricians. How large a
  25. Physics

    A computer and monitor use 800J of electric energy each second. The monitor produces 30J of light energy each second. The fan in the computer converts 15J each second into kinetic energy. The lights on the tower give off 10J of light energy. If all the
  26. physics

    An object of mass 26 kg is thrown straight upwards from the ground at 27 m/s. Due to air resistance (a non-conservative force), the object loses some of its initial energy during its trip to reach maximum height and only travels to a height above the
  27. Chemistry

    A student is given 2.94g of a mixture containing anhydrous MgCl2 and KNO3. To determine the percentage by mass of MgCl2 in the mixture, the student uses excess AgNO3 to precipitate the chlorides ios as AgCl Starting with the 2.94g sample of the mixture
  28. Math

    90% of students at a university use a backpack, while the rest do not. Of all the students, 50% carry their laptops with them and 5% carry neither a backpack nor laptop. What percentage of students carry their laptops and use a backpack?
  29. Maths

    There are 20 questions in a test. Faye answers 17 correctly. a. What fraction of questions does faye answer correctly? b. What percentage of the questions does Faye answer correctly?
  30. math

    Suppose a test of musical ability has a normal distribution with a mean of 50 and a standard deviation of 5. Approximately what percentage of people are over 55? a. 6% b. 16% c. 45% d. 84% A z-score of 1.75 indicates how many standard deviation units above
  31. Some Body Plz help math Nca

    The table below shows the percentage of households that own a microwave in different countries. Construct a stem-and-leaf plot of the data. Country Percent Of Household With Microwave Ovens _____________________________________________________________
  32. statistics

    Suppose that diastolic blood pressure readings of adult males have a bell-shaped distribution with a mean of 84 84 mmHg and a standard deviation of 9 9 mmHg. Using the empirical rule, what percentage of adult males have diastolic blood pressure readings
  33. statistics

    11. (4 pts) The following statistics provide information about the scores on a national mathematics exam. Mean 312 First Quartile 201 Median 296 Third Quartile 423 Mode 326 49th Percentile 307 a) What score did half of the test takers surpass? b) What was
  34. statistics

    11. (4 pts) The following statistics provide information about the scores on a national mathematics exam. Mean 312 First Quartile 201 Median 296 Third Quartile 423 Mode 326 49th Percentile 307 a) What score did half of the test takers surpass? b) What was
  35. statistics

    The pucks used by the National Hockey League for ice hockey must weigh between 5.5 and 6.0 ounces. Suppose the weights of pucks produced at a factory are normally distributed with a mean of 5.75 ounces and a standard deviation of 0.11 ounce. What
  36. 7th grade

    A company made 34,000.00 in 2007. This company made 32,500.00 in 2008. What is the percentage of the difference. The difference is 1,500.00 Is the difference 44.3 %? 34,000.00 32,500.00 _________ 66,500.00
  37. Math

    Suppose in the early 1900s the levels of CO2 in the atmosphere was only 64% of the levels of CO2 today. What percentage more is the level of CO2 today compared to the levels of CO2 in the early 1900s?
  38. Chemistry

    Hi, I posted a question yesterday : A compound contains only carbon, hydrogen, nitrogen, and oxygen. Combustion of 0.157 of the compound produced 0.213g CO2 and 0.0310 g H20. In another experiment, it is found that 0.103g of the compound produces 0.0230 g
  39. Chemistry

    One mole of nirtogen at 273K occupying 10 litres (state 1) is to be expanded to a volume of 20 litres at 373K (state 2). An infinite number of paths from state 1 to state 2 are possible. Consider the following important paths: (a) The gas is expanded
  40. statistics

    Suppose that the percentage returns for a given year for all stocks listed on the New York Stock Exchange are approximately normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent. Consider drawing a random sample of n= 5
  41. Economics

    Consider an economy with a constant nominal money supply, a constant level of real output Y = 100, and a constant real interest rate, r = 0.10. Suppose that the income elasticity of demand is 0.5 and the interest elasticity of money demand is –0.1. By
  42. math

    A company has a policy of retiring company cars; this policy looks at number of miles driven, purpose of trips, style of car and other features. The distribution of the number of months in service for the fleet of cars is bell-shaped and has a mean of 55
  43. Statistics

    Suppose that the percentage returns for a given year for all stocks listed on the New York Stock Exchange are approximately normally distributed with a mean of 12.4 percent and a standard deviation of 20.6 percent. Consider drawing a random sample of n= 5
  44. math

    A company has a policy of retiring company cars; this policy looks at number of miles driven, purpose of trips, style of car and other features. The distribution of the number of months in service for the fleet of cars is bell-shaped and has a mean of 55
  45. math

    A company has a policy of retiring company cars; this policy looks at number of miles driven, purpose of trips, style of car and other features. The distribution of the number of months in service for the fleet of cars is bell-shaped and has a mean of 55
  46. math

    Reading readiness of preschoolers from an impoverished neighborhood (n = 20) was measured using a standardized test. Nationally, the mean on this test for preschoolers is 30.9, with s = 2.08. a.Children below the 30th percentile are in need of special
  47. math

    60 ml of solution A is mixed with 120 ml of solution B to produce solution C which contains 8% of pure acid. If 80ml of solution A is mixed with 40ml of solution B, a solution D containing 10% of pure acid can be produced. find the percentage of pure acid
  48. chemistry

    A mixture of CaCO3 and MgCO3 weighing 7.85 g was reacted with excess HCL. The reactions are CaCO3+2HCL=CaCl2+H2O+CO2 and MgCO3+2HCl=MgCl2+H2O+CO2. The sample reacted completely to produce 1.94 L CO2 at 25 degrees C and 785 torr. Calculate the percentage of
  49. Physics

    Let's assume that solar light reaches a silicon solar cell with an angle of incidence of θi=0o. For simplicity, let's consider the refractive index of silicon to be nSi=3.5. The refractive index of air is nair=1. What percentage of light would be lost
  50. math

    the last week of the month a car dealership sold 12 cars.A new sale promotion came out the first week of the month and sold 19 cars that week what was the percentage increase in sale from the last week of the previous month compared to the first week of
  51. Algebra

    A school planned to buy x calculators for a total cost of Ksh 16200. The supplier agreed to offer a discount of Ksh 60 per calculator. The school was the able to get three extra calculators for the same amount of money. (a) Write an expression in terms of
  52. Math

    A school planned to buy x calculators for a total cost of Ksh 16200. The supplier agreed to offer a discount of Ksh 60 per calculator. The school was the able to get three extra calculators for the same amount of money. (a) Write an expression in terms of
  53. math

    can please someone check my answer Q.) 30% of the adult population was offline in terms of being able or willing to access the internet. New data relating to the year 2010 (sourced from The Office for National Statistics) indicated that this group numbered
  54. MATHS

    Ken and Sam shared some marbles. The ratio of the number of marbles Ken has to the number of marbles Sam has is 5:3. If Ken's marbles increases by 15%, what percentage of Sam's marbles must be decreased so that the total number of marbles they have
  55. Math

    Ken and Sam shared some marbles. The ratio of the number of marbles Ken has to the number of marbles Sam has is 5:3. If Ken's marbles increases by 15%, what percentage of Sam's marbles must be decreased so that the total number of marbles they have
  56. Calculus I, differentiation

    The number, N, of people who have heard a rumor spread by mass media by time, t, is given by N(t)=a(1−e−kt). There are 6 million people in the population, who hear the rumor eventually. If 5% of them heard it on the first day, find the
  57. statistics

    A company has been studying the performance of their sales department. The measure of performance used is: average monthly sales amount in dollars. For the past 12 months, the average monthly sales amount has been $4,532 with a standard deviation of $386.
  58. statistics

    3 In 1999, a sample of 200 in-store shoppers showed that 42 paid by debit card. In 2004, a sample of the same size showed that 62 paid by debit card. (a) Formulate appropriate hypotheses to test whether the percentage of debit card shoppers increased. (b)
  59. chemistry. please help drbob222

    One of the reactions involved in the smelting of copper sulfide ores involves copper (I) oxide and copper (I) sulfide: 2Cu2O2 + Cu2S ---> 6Cu + SO2 Assuming that 35.00 g of copper (I) oxide is heated with 25.00 g of copper (I) sulfide A) determine which
  60. SS! HARD!

    How U.S. Citizens Want to Balance the Budget, July 2011 Chart: (Survey conducted July 7-10, 2011, with a random sample of 1,016 adults, For results based on the total sample of national adults, one can say with 95% confidence that the maximum margin of
  61. Chemistry

    When 9.0g of Al were treated with an excess of chlorine, 20.0g of Al2Cl6 were collected. 2AL + 3Cl6 -------> Al2Cl6 What was the percentage yield? This is what i did so far # moles in Al = 0.333 # moles in Cl2 = 0.282 The limiting reactant = Cl2 27g of
  62. please help me!! with this science!!!!!

    Multiple Choice: 1. If a kestrel eats a mouse that eats grass, the kestrel is a (1 point) producer. second-level consumer. first-level consumer. decomposer. 2. Which of the following best explains why a species of lizard is able to live in the desert but
  63. insulin-food intake

    Through which mechanism does insulin affect food intake? a. it enables the intestines to digest certain types of protein that they would not otherwise be able to digest b. it increases the percentage of each meal that is stored as fats c. it increases the
  64. insulin-food intake

    Through which mechanism does insulin affect food intake? a. it enables the intestines to digest certain types of protein that they would not otherwise be able to digest b. it increases the percentage of each meal that is stored as fats c. it increases the
  65. Algebra 2

    According to a survey conducted in 1990 by Independent Sector, the percent of their incomes that Americans give to charities is related to their household incomes. For families with annual incomes between $5000 and $100,000, the percent is modeled by P =
  66. insulin - food intake

    Through which mechanism does insulin affect food intake? a. it enables the intestines to digest certain types of protein that they would not otherwise be able to digest b. it increases the percentage of each meal that is stored as fats c. it increases the
  67. Science

    7. The mutation for cataracts (c) occurs on a gene represented by the letter E. Owls that are homozygous for the mutation (EcEc) exhibit cataracts. Owls that are homozygous for normal eyes are EE and owls that are carriers of the mutation but do not
  68. tech AGAIN

    3) Which of the following sets of data would be represented best in a bar graph? A.the number of hot dogs consumed by the people entered in a hot dog eating contest b. the percentage of hot dogs consumed by women c. the number of hot dogs consumed by the
  69. Science (chemistry)

    Write a balanced chemical equation and state the reaction type for each of the following reactions: a.) nitrogen gas reacts with hydrogen gas forming ammonia (NH3) b.) carbonic acid breaks down to form carbon dioxide gas and water c.) aluminum foil reacts
  70. statistics

    Wages and salaries make up only part of a total compensation. Other parts include paid leave, health insurance, and many others. In 2007, wages and salaries among manufacturers in the United States made up an average of 65.8% of total compensation. To
  71. Statistics

    . Wildlife biologists inspect 153 deer taken by hunters and find 32 of them carrying ticks that test positive for Lyme disease. a) Construct and interpret a 90% confidence interval for the percentage of deer that may carry such ticks. Show all work and
  72. Stats - Help!!!

    One month before a recall election, a poll of 500 Wisconsin voters showed that 46% planned to vote for the Democratic challenger Tom Barrett and 45% planned to vote for Republican Governor Scott Walker. Undecided voters constituted another 9%. The margin
  73. Statistics

    One month before a recall election, a poll of 500 Wisconsin voters showed that 46% planned to vote for the Democratic challenger Tom Barrett and 45% planned to vote for Republican Governor Scott Walker. Undecided voters constituted another 9%. The margin
  74. Science

    What can scientists learn from the rate at which radioactive elements decay? A. a rock's absolute age* B. the relative age of rock layers C. where one soil horizon ends and the next begins D. the difference between molds and casts. After six half-lives,
  75. Science

    What can scientists learn from the rate at which radioactive elements decay? A. a rock's absolute age* B. the relative age of rock layers C. where one soil horizon ends and the next begins D. the difference between molds and casts. After six half-lives,
  76. Science

    What can scientists learn from the rate at which radioactive elements decay? A. a rock's absolute age* B. the relative age of rock layers C. where one soil horizon ends and the next begins D. the difference between molds and casts. After six half-lives,
  77. English

    Does this sound like an indirect quote? I put it in quotations. One of the biggest problems with animal testing is the fact that animals are extremely different from humans, therefore they make bad test subjects. "The National Institutes of Health has
  78. Chemistry

    You are given 2.677 g of a mixture of KClO3 and KCl. When heated, the KClO3 decomposes to KCl and O2, 2 KClO3 (s) → 2 KCl (s) + 3 O2 (g), and 605 mL of O2 is collected over water at 28 °C. The total pressure of the gases in the collection flask is
  79. Chemistry

    I need some help with some of these questions: The action of bacteria on meat and fish produces a poisonous compound called cadaverine. As its name implies, it stinks! It is 58.77 percent carbon, 13.81 percent hydrogen, and 27.40 percent nitrogen. Its
  80. Chemistry

    I need some help with some of these questions: The action of bacteria on meat and fish produces a poisonous compound called cadaverine. As its name implies, it stinks! It is 58.77 percent carbon, 13.81 percent hydrogen, and 27.40 percent nitrogen. Its
  81. science

    if i had mixture of sodium carbonate and sand, and spilled some sodium carbonate (no sand spilled) after weighing the mixture, would the spill affect the percentage of sand or sodium carbonate when we calculate it?
  82. Chemistry

    The tin (II) fluoride in a 10.000 g sample of toothpaste is extracted into solution and them a precipitate of lanthanum (II) fluoride (LaF3) is formed by the addition of a lanthanum (III) nitrate solution. If the mass of the lanthanum (III) fluoride
  83. Math: Personal Finance

    In order to buy a new car, you finance $20,000 with no down payment for a term of five years at an APR (Annual Percentage Rate) of 6%. After you have the car for one year, you are in an accident. No one is injured, but the car is totaled. The insurance
  84. Accounting

    a net loss of $50,000 in 2009 and net income of $250,000 in 2010. The increase in net income of $300,000 can be stated as 200% increase cannot be stated as a percentage can be stated as 0% can be stated as 100% increase
  85. chemistry

    Fructose is a sugar commonly found in fruit. A sample of fructose, C6H12O6, weighing 4.50 g is burned in a bomb calorimeter. The heat capacity of the colorimeter is 2.115 E4 J/ºC. The temperature in the calorimeter rises from 23.49ºC to 27.71ºC. A)What
  86. Chemistry

    If I added sodium carbonate to magnesium nitrate, would it be insoluble & a precipitate forms? If I added sodium carbonate to calcium nitrate, would it be insoluble & precipitate forms? Adding sodium carbonate to strontium nitrate: insoluble, precipitate
  87. pHYSIC

    3. Now wait until the planet is at the summer solstice (to the far left). Here the sunlight arrives perpendicular to the surface. (Note that the fact that the sunlight can be perpendicular to the surface here and parallel to the surface at the winter
  88. Educational technology and online learning

    Which of the following sets is data would be represented best in a bar graph? A. the number of hot dogs consumed by the people entered in a hot dog eating contests B. The percentage of hot dogs consumed my women? C.the number of hot dogs consumed by the
  89. Statistics

    A high school counselor is interested in the percentage of students who will be going to college. She randomly picks 60 students and finds that 53 will be going to college. Use a 95% confidence level to find the population proportion. a) State the 95%
  90. chem

    a) Calculate the pressure exerted by 0.5160 mol N2 in a 1.0000 L container at 24.6°C using the ideal gas law. atm (b) Calculate the pressure exerted by 0.5160 mol N2 in a 1.0000 L container at 24.6°C using the van der Waals equation. atm (c) Compare the
  91. statistic

    A final exam in Math 160 has a mean of 73 with standard deviation 7.73. Assume that a random sample of 24 students is selected and the test score of the sample is computed. Assuming the scores are normally​ distributed, what percentage of sample
  92. Statistics

    In a certain microwave oven on the high power setting, the time it takes a randomly chosen kernel of popcorn to pop is normally distributed with a mean of 140 seconds and a standard deviation of 25 seconds. What percentage of the kernels will fail to pop
  93. biology

    You are conducting an experiment to determine whether lichen populations are affected by local airborne pollutants. Which of the following observations would best support your hypothesis that high levels of pollutants in rainwater cause a reduction in
  94. Economics

    This chart shows the components of nominal GDP for the years 2000 and 2001. All figures are in billions of current dollars. -------------------------------------------------------------------------------- Components 2000 2001
  95. Chemistry

    Why is magnesium atom smaller than atoms of both sodium and calcium? The location of the outer electrons for Mg are in closer to the nucleus than of Sodium or Calcium. To add to the correct answer from Bob Pursley, consider the electronic configurations.
  96. Chemistry

    The quantity of antimony in a sample can be determined by an oxidation-reduction titration with an oxidizing agent. A 7.79-g sample of stibnite, an ore of antimony, is dissolved in hot, concentrated HCl(aq) and passed over a reducing agent so that all the
  97. maths

    the blood alcohol concentration(BAC)in the uk is 0.08%. A well known formula for calculating BAC percentage is widmarks formula BAC%=5.14A/rW -0.015H Where A is the total alcohol consumed in ounces, W is the body weight in pounds, r isthe alcohol
  98. percentage

    Chitra used wheat flour&plain flour to bake some cakes.19%of the flour used was wheat flour.if she used 475g of flour,find: A) the total mass of flour she used for the cakes B) the mass of plain flour she used
  99. chemistry

    One of the reactions involved in the smelting of copper sulfide ores involves copper(I) oxide and copper (I) sulfide: 2Cu2O(solid) + Cu2S(solid) ---> 6Cu(solid) + SO2(gas) Assuming that 35.00 g of copper (I) oxide is heated with 25.00 g of copper (I)
  100. statistics

    The latest in the "You may be a redneck if . . . " genre has produced a simple questionnaire. If more than 80% of the questions are answered in accordance with redneck"philosophy" (e.g., "You may be a redneck if grade 4 was the best 5 years of your life")