1. Chemistry

    a compound of nitrogen and oxygen is 30.46% by mass N and 69.54% by mass O. the molar mass if the compound was determined to be 92g/mol. What is the empirical formula of the compound? What is the molecular formula of the compound?
  2. Chemistry

    If the percentage yield of a reaction was 78.51% and the theoretical yield was 288.0 g, what was the actual yield?
  3. math

    in 2010 i had 36 plums and in 2013 i now have 25 plums, what is the percentage of plums i have cut back on
  4. Math

    Each digit of a four-digit PIN can be any number from 0 to 9. What is the percentage of PINs with no digit repeated more than twice?
  5. Science

    A researcher wants to experiment with an element that reacts like phosphorus (P) but has a greater atomic mass. Which element should the researcher select for the experiment? A. Nitrogen (N) B. Sulfur (S) C. Arsenic (As) D. Silicon (Si) I choose Arsenic,
  6. chem

    mass of mg- .28 mass of o- .41 calculate the moles of mg and o what is the simples whole number ratio of the moles of mg to the moles of o? round off to the nearest whole number ratio. use this mole ratio to write the empirical formula. the molecular mass
  7. nursing

    The percentage of people under 30 is the lowest it has ever been in recorded history for the U.S. What do you feel could be done to change the publics perception of nursing. What trends in the nursing profession do you consider troubling, what gives you
  8. Chemistry

    bromine has two isotopes Br,79 and Br-81 the relative atomic mass of bromine is 79.9 calculate the percentage or br 79 atoms in a sample of bromine show all working out with all equations used and no abbreviations please
  9. Are my answers correct? Chem

    I really need help with balancing these equations: Can you check if my answer are correct? Please 1. Sodium Hydrogen Sulfite reacts with hydrochloric acid to produce sulfur dioxide gas, water and sodium chloride NaHSO3 + HCl = SO2 + H2O + NaCl 2. Sodium
  10. Finance

    Real and nominal rates interest   Zane Perelli currently has ​$120 that he can spend today on polo shirts costing $ 30 each. ​ Alternatively, he could invest the ​$120 in a​ risk-free U.S. Treasury security that is expected to earn
  11. Chemistry

    Can zinc (Zn) react with one of these: Al(NO3)3 aluminum nitrate Mg(NO3)2 magnesium nitrate Zn(NO3)2 zinc nitrate Cu(NO3)2 copper nitrate?
  12. Chemistry

    Write the chemical formulas for the compounds containing each of the following: a) one calcium atom for every two iodide atoms. b) two nitrogen atoms for every four oxygen atoms. c) one silicon atom for every two oxygen atoms. d) one zinc atom for every
  13. Chemistry

    Write the chemical formulas for the compounds containing each of the following: a) one calcium atom for every two iodide atoms. b) two nitrogen atoms for every four oxygen atoms. c) one silicon atom for every two oxygen atoms. d) one zinc atom for every
  14. Math 115

    The United States emitted 19.5 million t of nitrogen oxides (NO) into the atmosphere in 1987. One metric ton (1 t) equals 1,000 kg. How many kilograms of NO were emitted to the atmosphere in the United States during 1987?
  15. college general chem

    If 15.0 of is dissolved in enough water to form 270 of solution, what is the molarity of the solution? What is the oxidation state of an individual sulfur atom in ? What is the oxidation state of an individual nitrogen atom in ?
  16. Chemistry, please help!

    The average human body contains 6.20 L of blood with a concentration of 2.40×10−5 M . If a person ingests 8.00 mL of 13.0 mM NaCN, what percentage of iron(II) in the blood would be sequestered by the cyanide ion? According to the equation: Fe2+ +
  17. Math

    the function 160x/100-x,models the cost,f(x), in millions of dollars,to remove x% of a river pollutants,if the government commits 240 million for this project, what percentage of pollutants can be removed?
  18. algebra

    400 Learners attended High School of the future for 4 days this past week. If 7 students were caught violating the uniform policy, what percentage was the overall compliance for the entire week???
  19. math

    the average middle distance runner at a local high school runs the mile in 4.5 minutes with a standard deviation of 0.3 minute the percentage of a runners that will run the mile in less than 4 min is %
  20. chemistry

    Calcium carbonate was reacted with hydrogen chloride. What is the percentage yield of carbon(iv)oxide produced if 3.65g of the gas is collected when 10g of calcium(iii)oxocarbonate reacts
  21. Sta

    A regular feature in a newspaper asks readers to respond via e-mail to a survey that requires a yes or no response. In the following day's newspaper, the percentage of yes and no responses are reported. discuss why we should ignore these statistics.
  22. chemistry

    A solution is made by dissolving 7.084 g of aluminum nitrate, Al(NO3)3, in 123.0 g of water. What is the mass percentage of solute in this solution? this feels like a simple problem but i just don't know. divide the two?
  23. math

    The functionf(x) = 300x/100-x models the cost, F(x) in m illions of dollars to remove x% of a rivers pollutants. If the government commits $325 million for this project, what percentage of the pollutants can be removed?
  24. Jenish

    A 1200 W hair dryer is designed for 117 v. a) What will be the percentage change in power output if the voltage drops to 105 v. b) How would the actual change in resistivity with temperature affect your answer.
  25. chem

    help, i'd like to know how to do this titration question: for example: a 1g sample of naoh contaminated with na2co3 is titrated with 0.500MHCl, and it is found that 46.5mL of HCl are required for neutralization. Find the percentage by mass Na2Co3. thank
  26. math

    obesity is defined as a body mass index of 30kg/m2 or more. A 95% confidence interval for the percentage of U.S. adults aged 20 years and over who were obesity was found to be 22.4 to 23.5%. What was the sample size???? Can you please show your work??
  27. six sigma

    If the mean value of the weight of a particular brand of dog food bag is 20.6 pounds and the standard deviation is 1.3, assume a normal distribution and calculate the percentage of bags that falls below the lower specification value of 19.7 pounds.
  28. Language Arts

    All of the following sentences are complex EXCEPT A) Even though acid rain can have damaging effects, few people know much about it. B) Acid rain has been studied as an environmental issue by the government since the 1970s. C) Since they erode statues and
  29. Chemistry

    Suppose there is a simulation of 25 helium molecules and 25 nitrogen molecules on the right hide of a box before the rate of effusion. Suppose you carry out this simulation and it does not give a precise quantitative reflection of Graham's Law. -->What
  30. Chemistry: Need Help

    Suppose there is a simulation of 25 helium molecules and 25 nitrogen molecules on the right side of a box before the rate of effusion. Suppose you carry out this simulation and it does not give a precise quantitative reflection of Graham's Law. -->What
  31. chemistry

    How will the relative number of moles of Mg and O be affected if the following procedural errors are made? Briefly explain (1) the crubile is not brought to constatn mass before the Mg is added. (2) water is not added after the first heating of Mg, and the
  32. Statistics

    To plan the budget for next year a college needs to estimate what impact current economic downturn might have on student requests for financial aid. Historically, this college has provided aid to 35% of its students. Officials look at a random sample of
  33. Statistics Homework Check

    Hi! I had this one last question on my homework that I wasn't sure about, but, I need someone to check this for me and see if this is right. Thanks so much! Question: The study that looked at prevalence of various appliance in homes in 2001 made a
  34. Statistics Homework Check

    Hi! I had this one last question on my homework that I wasn't sure about, but, I need someone to check this for me and see if this is right. Thanks so much! Question: The study that looked at prevalence of various appliance in homes in 2001 made a
  35. Statistics

    The level of nitrogen oxides (NOX) in the exhaust of a particular car model varies with mean 0.9 grams per mile and standard deviation 0.15 grams per mile . (a) What sample size is needed so that the standard deviation of the sampling distribution is 0.01
  36. Statistics

    he level of nitrogen oxides (NOX) in the exhaust of a particular car model varies with mean 0.7 grams per mile and standard deviation 0.19 grams per mile . (a) What sample size is needed so that the standard deviation of the sampling distribution is 0.01
  37. ANALYTICAL CHEMISTRY

    A 24-h urine specimen was diluted to 2.000L and buffered to pH 10.0. A 10.00 mL aliquot was titrated with 27.32 mL of 0.003960 M EDTA. The calcium in a second 10.00 mL aliquot was iso;ated as solid CaC2O4, redissolved and titrated with 12.21 mL of the EDTA
  38. Chemistry - Mass-Mass conversion & Percent yield

    Please show work 1. N2 (g) + 3H2(g) ---> 2NH3(g) 100.0 g of nitrogen reacts completely with excess hydrogen, and 34.0 g of NH3 are obtained what is the percent yield of ammonia? 2. 2Al (s) + 3Cl2(g) ---> 2AlCl3(s) Assume that 0.40 g of Al is mixed
  39. math

    the united states emitted 19.5 million of nitrogen oxides (NO) into the atmosphere in 1987. One metric ton (1t) equals 1,000kg. How many kilograms of NO were emitted to the atmosphere in the united states during 1987?
  40. Math

    The United States emitted 19.5 million t of nitrogen oxides (NO) into the atmosphere in 1987. One metric ton (1 t) equals 1,000 kg. How many kilograms of NO were emitted to the atmosphere in the United States during 1987?
  41. Chemistry

    PLEASE HELP!! On a clear day at sea level, with a temperature of 25 °C, the partial pressure of N2 in air is 79 kPa and the concentration of nitrogen in water is 5.3 x 10-4 M. When the partial pressure of N2 is ________ kPa, the concentration in water is
  42. math

    The united states emitted 19.5 million of nitrogen oxides (NO) into the atmosphere in 1987. ONe metric ton (1) equals 1,000 kg. How many kilograms of no were emitted to the atmosphere in the united states during 1987?
  43. chemistry again :)

    A compound containing only sulfur and nitrogen is 69.6% S by mass; the molar mass is 184 g/mol. What are the empirical and molecular formulas of the compound? i solved for empirical and got a 1:1 ratio so it would be SN. for the molecular do i take
  44. math

    The United States emitted 19.5 million t of nitrogen oxides (NO) into the atmosphere in 1987. One metric ton (1 t) equals 1,000 kg. How many kilograms of NO were emitted to the atmosphere in the United States during 1987?
  45. chemistry

    Nitrogen dioxide (NO2) cannot be obtained in a pure form in the gas phase because it exists as a mixture of NO2 and N2O4. At 23°C and 0.94 atm, the density of this gas mixture is 2.6 g/L. What is the partial pressure of each gas? NO2 N2O4
  46. chemistry

    A fuel mixture used in the early days of rocketry is composed of two liquids, hydrazine (N2H4) and dinitrogen tetraoxide (N2O4), which ignite on contact to form nitrogen gas and water vapor. 2 N2H4 + N2O4 --> 3 N2 + 6 H2O If 1.50 x 102 g of N2H4 and
  47. Chemistry

    Magnesium metal reacts with HCl(aq) according to the equation: Mg(s) + 2 HCl(aq) → MgCl2(aq) + H2(g) In an experiment to determine the ΔH for this reaction, 0.158 g of Mg metal is combined with an excess of HCl to make 100.0 mL of solution in a coffee
  48. Science

    At a given temperature and pressure, the volume of a gaseous sample is directly proportional to the moles of gas (volume = C * moles, where C is a constant). Assuming that the tempreature and pressure is the same for the reaction of magnesium with HCl(aq)
  49. Science

    At a given temperature and pressure, the volume of a gaseous sample is directly proportional to the moles of gas (volume = C * moles, where C is a constant). Assuming that the tempreature and pressure is the same for the reaction of magnesium with HCl(aq)
  50. Science

    At a given temperature and pressure, the volume of a gaseous sample is directly proportional to the moles of gas (volume = C * moles, where C is a constant). Assuming that the tempreature and pressure is the same for the reaction of magnesium with HCl(aq)
  51. Chemistry

    A 50.0 L reaction vessel contains 1.00 moles of nitrogen gas, 3.00 moles of hydrogen gas and 0.500 moles of ammonia gas. Explain how this reaction will proceed if Kc=0.500 at 400 degrees C. N2(g) + 3H2(g) ⇌ 2NH3(g)
  52. Chemistry

    Use the following information to identify element A and come pound B, then answer questions a and b. An empty glass container has a mass of 658.572 g. It has a mass of 659.452 g after it has been filled with nitrogen gas at a pressure of 790. torr and a
  53. Quick Help (URGENT)

    1. What percentage of teen parents live in poverty? Is it 75 percent?? 2. How can you get HIV? Unprotected sex, anal, oral, vaginal. 3. What are the other methods of transmission of HIV? ??? Can someone check over my answers and help me with number 3?
  54. Physics

    If a drummer at a gig hits his a drum that has a diameter of .2m with a stick that has a mass of 0.5kg at .03m from the center. What percentage radial region is impacted with a force twice as great as the initial impact force?
  55. math

    a pharmacist measures 60mL of glycerin by difference, starting with 100mL. After completing the measurement, he notes the graduate he used contained 45mL of glycerin. calculate the percentage of error incurred in the measure.
  56. general chemistry I

    Calculate the percentage error arising in an experiment if 1-mL, 5-mL, and 10-mL pipets are used for transfer and each pipet contains 5 drops of water adhering to the inside of the barrel. A single drop of water has an approximate volume of 0.05 mL.
  57. Chemistry

    The average human body contains 5.30L of blood with a Fe2+ concentration of 2.30×10−5M . If a person ingests 11.0mL of 15.0mM NaCN , what percentage of iron(II) in the blood would be sequestered by the cyanide ion?
  58. Chemistry

    2 moles of helium (He) are pumped from a gas canister into a weather balloon. The balloon at this point has a volume V1. 1 mole of nitrogen gas (N2) is added at the same temperature and pressure. The volume of the balloon changes to V2. How will the new
  59. epidemiology

    The prevalence of previously undetected diabetes in a population to be screened is approximately 1.5% and it is assumed that 10,000 persons will be screened. The screening test will measure blood serum sugar content. A value of 180 mg percent or higher is
  60. IUPUI

    The prevalence of previously undetected diabetes in a population to be screened is approximately 1.5% and it is assumed that 10,000 persons will be screened. The screening test will measure blood serum sugar content. A value of 180 mg percent or higher is
  61. Science

    You are a Chemical engineer, trying to synthesize N2H4(l). Your boss suggests that you try to synthesis it from the elements, nitrogen and hydrogen, at 25 celsius and 1.0 atm (since this would be a cheap way of doing it). Write a short note to sent to your
  62. fanince

    ) A thirty-year U.S Treasury bond has a 4.0 percent interest rate. In Contrast, a ten-year Treasury bond has an interest rate of 2.5 percent. A maturity risk premium is estimated to be 0.2 percentage points for the Longer maturity bond. Investors expect
  63. math

    The United States emitted 19.5 million t of nitrogen oxides (No) into the atmosphere in 1987. One metric to (1t) equals 1,000 kg. How many kilograms of NO were emitted to the atmosphere in the United States during 1987?
  64. History

    Of the following,which occurred after the stock market crash in 1929? 1.The establishment of the Federal Deposit Insurance Corporation 2.The Wealth in the country owned by a small percentage of people 3.stocks being bough on the margin 4.use of credit to
  65. Maths

    In a class of 60 students,45 students are female. What percentage (%) of the students are male.
  66. Chemistry pH

    A 0.60 M solution of a weak acid, HA, has a pH of 3.72. What is the percentage ionization of the acid? What is the value of Ka for the acid?
  67. Chemistry

    A 0.60 M solution of a weak acid, HA, has a pH of 3.72. What is the percentage ionization of the acid? What is the value of Ka for the acid?
  68. chemistry

    An orgnaic compound contains C, H, No, and O. Combustion of 0.1023 g of the compound in excess oxygen yielded 0.2766 g of CO2 and 0.991g of H2O. A asample of 0.4831 g of the compound was analyzed for nitrogen by the Dumas method. At STP, 27.6 mL of dry
  69. chemistry - kinetics

    Understanding the high-temperature behavior of nitrogen oxides is essential for controlling pollution generated in automobile engines. The decomposition of nitric oxide (NO) to N2 and O2 is second order with a rate constant of 0.0796 M−1*s−1 at
  70. Organic Chemistry lab

    So we did a preparation of t-pentyl Chloride experiment in class the other day using t-pentyl alcohol, HCL, Aqueous sodium Bicarbonate, and calcium chloride as the drying agent. Little confused on a few of these questions Why is calcium chloride used as
  71. General Chem

    At a given temperature and pressure, the volume of a gaseous sample is directly proportional to the moles of gas (volume = C * moles, where C is a constant). Assuming that the tempreature and pressure is the same for the reaction of magnesium with HCl(aq)
  72. Marine Science

    I've searched and read so many things but i have yet to find the answer that my teacher is looking for. What percentage of energy is transferred from a producer to a: (A) secondary consumer, (B) tertiary consumer, (C) quaternary consumer?
  73. geometry

    Please reference the illustration at screenshots<dot>firefox<dot>com/kzZjGCIcg9EMQ0MH/brilliant<dot>org to answer the following question: What percentage of the square's area is colored blue? 30% 35% 40% 45% 50%
  74. Math

    Use the normal distribution of weights of adult men, which has a mean of 170 pounds and a standard deviation of 7.5 pounds. Use the z-score chart to find the percentage of heights less than 155 pounds.
  75. staistics

    7) A final exam in Statistics has a mean of 73 with a standard deviation of 7.73. Assume that a random sample of 24 students is selected and the mean test score of the sample is computed. What percentage of sample means are less than 70?
  76. chemistry

    1.00 tonne of ammonium from the harber process is reacted with carbon dioxide to prepare the fertiliser urea and 1.35 tonnes of urea are formed. calculate the percentage yield of urea
  77. chemistry

    I am given the following reaction: 2NH3(g) -----> N2(g) + 3H2(g) 6.4 mols of ammonia gas has been put into a 1.7 L flask and has been permitted to reach equilibrium in accordance to the reaction listed above. If the equilibrium mixture has 4.2 mols of
  78. Chem

    Please help are these right? A 2.3 mole sample of nitrogen (N2), has a volume of 50.0 L and a pressure of 630 mmHg. What is the temperature of the gas? 41.5 C which I converted to Kelvin and got 231.5K Calculate the molarity (M) of the following solutions:
  79. CHEMISTRY

    In the analysis of food, the nitrogen from the protein is sometimes converted into ammonia which is titrated against a strong acid. Given that the final NH3 concentration (approximate) is 0.2M and that pKa for NH4+ is 9.2, choose the best indicator for
  80. chemistry

    Changing 1 mol of Mg(s) and 1/2 mol of O2 (g) to gaseous atoms requires a total of approximately 150kJ of energy. The first and second ionization energies of Mg are 737kJ/mol and 1450kJ/mol respectively. The first and second electron affinities of Oxygen
  81. Chemistry.

    I need to know if these two statements are always true, AT; sometimes true, ST; or never true, NT. Thanks! 10. A mole of carbon atoms has a mass approximately three times as great as the mass of a mole of helium atoms. 11. The gram molecular mass of
  82. Chemistry

    10.0 mol of ammonia gas is injected into a 4.0 L container. At equilibrium 1.2 mol of nitrogen gas is found in the container. The number of moles of ammonia gas left in the container must be which of the following? N2(g) + 3H2(g) <=====> 2NH3(g) + 94
  83. chemistry

    Using the activity series, write a balanced chemical equation for the following reactions: 1. iron metal is added to a solution of copper (II) nitrate 2. zinc metal is added to a solution of magnesium sulfate 3. hydrobromic acid is added to tin metal 4.
  84. Chemistry

    Nitric acid can be produced by the reaction of gaseous nitrogen dioxide with water. 3 NO2(g) + H2O(ℓ) −→ 2 HNO3(ℓ) + NO(g) If 916 L of NO2 gas react with water, what volume of NO gas will be produced? Assume the gases are measured
  85. Chemistry

    I havent been at school for 8 days due to somthing wrong with my heart, but the teachers gave me work. I have no clue how to do them. I really need help please, There all due tomarrow. Ammonia is formed by reacting nitrogen and hydrogen gases. How many
  86. Chemistry

    1. Suppose o2, n2 and Ar were placed at 1.00 atm and 273 K in closed containers. A tiny hole is opened in each container, allowing each gas to diffuse into another container filled with neon gas. What is the ratio of the rate of diffusion of nitrogen to
  87. chemistry

    THe thiocyanate ion acts as a Lewis base, donating a pair of electrons to the Fe ^ 3+ ion. Both sulfur and nitrogen atoms have lone pair electrons that can potentially be donated. Therefore, ther are two different structures (linkage isomers) that can be
  88. math

    If the store purchases an item at a wholesale cost of $3.50 per item, and it is sold at a retail value of $5.00 per item. What is the gross profit percentage of the item?
  89. geometry

    if the length of each edge in a cube is increased by the same percent and the result was a cube that had 25% more volume than it originally had, by what percentage were the edges increased
  90. psychology

    Suppose that the scores of architects on a particular creativity test are normally distributed. Using a normal curve table, what percentage of architects have Z-scores: Above .10 = Below .10 = Above .20 = Below .20 = Above 1.10 = Below 1.10 = Above -.10 =
  91. statistics

    Test scores on the ACT exam are normally distributed with a mean of 211 and deviation of 4.8. Using the 68-95-99.7 rule, find the percentage of ACT scores within 9.6 of the mean of 21.1, and 14.4 of the mean of 21.1
  92. Florida Science Grade 8

    Saturn's atmosphere consists of 75.3% hydrogen and 24.25% helium.what percentage of Saturn's atmosphere is made up of other gases?
  93. class

    Suppose that the scores of architects on a particular creativity test are normally distributed. Using a normal curve table, what percentage of architects have Z-scores: Above .10? Below .10? Above .20? Below .20? Above 1.10? Below 1.10? Above -.10? Below
  94. physics

    a compound consist of carbon,hydrogen and oxygen only.the percentage by mass are carbon 40.0% and 6,7% hydrogen.calculate the empirical formulae
  95. maths(percentage)

    the annual salary of a clerk in 1998 was rs.10800. It was increased by15% in 1989 and again by 15% in 1990. What was his salary in 1990
  96. math

    please help forgot how to do it What was the percentage increase in the age 75+ population of Europe from 1970 to 1995? 1970,22,762,1995,38,139
  97. math

    What is 6.5%of 40? Showing work 0.065 x   40 -------------   2.600 that is 2.6 just reverse what you would to to get a percentage. 40 times .065 = 2.6
  98. Science

    Approximately what percentage of the estimated age of Earth does the Cenozoic Era represent and how do you know? look at pg. 9 in Earth Science Reference Tables? a. 1.4% b. 5.0% c. 11.9% d. 65.0%
  99. Statistics

    Suppose that the scores of architects on a particular creativity test are normally distributed. Using a normal curve table, what percentage of architects have Z scores (a) above .10, (b) below .10, (c) above .20, (d) below .20, (e) above 1.10, (f) below
  100. science need help

    using the punnet square one trait is Dd and the other is dd. 1) does the mother or father in a have dimples b) what percentage of children are likely to have dimples i think for a: it is the father because of the D so that it dominant and b:50 because two