1. Chemistry

    Nitrogen Oxides, NOx (mixture of NO and NO2). The NOx in the atmosphere is slowly broken down to N2 and O2 in a first-order reaction. The average half-life of NOx in the smokestack emissions in a large city during daylight is 3.9 hours. (a) Starting with
  2. Environmental Science

    #34. In two or three well-developed paragraphs, name and describe the five primary air pollutants and provide several sources of each. my answer: There are five primary air pollutants and some sources of each of them. The first pollutant is Carbon monoxide
  3. Environmental Science

    #34. In two or three well-developed paragraphs, name and describe the five primary air pollutants and provide several sources of each. my answer: There are five primary air pollutants and some sources of each of them. The first pollutant is Carbon monoxide
  4. Math

    In 1995 the united states recovered 21% of its municiple solid waste through recycling up from 17% in 1990. Let y represent the percentage recycled and let x equal the number of years since 1990. Find the linear function that fits this data.
  5. chemistry

    treatment of a 0.400g sample of impure potassium chloride with an excess of AgNO3 resulted in the formation of 0.733g of AgCl. calculate the percentage of KCl in the sample. show balanced equations in support of your answer
  6. math

    Cazz receives a semimonthly paycheck from a jazz club of $4,500.00. He is married and is entitled to 1 withholding allowance. Using the percentage method, calculate the amount of income tax that should be withheld from his paycheck each pay period.
  7. chemistry

    The laboratory technician accidentally mixed NaHCO3 with BaCl2*2H2O instead of KCl when preparing unknown mixtures for this experiment. How would this mistake affect the calculated percentage of NaHCO3 in the mixture? Justify your answer with an
  8. Chemistry

    1.2048g sample of impure Na2CO3 is dissolved and allowed to react with a solution of CaCl2 resulting CaCO3 after precipitation, filtaration and drying was found to weight 1.0362g. calculate the percentage purity of Na2CO3
  9. chemistry

    Mixtures of helium and oxygen are used in scuba diving tanks to help prevent ‘the bends’, a condition caused by nitrogen bubbles forming in the bloodstream. If 95 L of oxygen and 25 L of helium at STP are pumped into a scuba tank with a volume of 8.0
  10. Chemistry

    Nitrogen dioxide, NO2, dimerizes easily to form dinitrogen tetroxide , N2O4 : 2NO2<===>N2O4 a) Calculate Change in reaction G* and K for this equilibrium. b) Calculate the (e) (the measure of the progress of the reaction) for this equilibrium if 1.00
  11. Chemistry

    Virtually all the nitric acid manufactured commercially is obtained by the ammonia oxidization process. This involves this first step: Ammonia gas combines with oxygen to form nitrogen monoxide and water vapour. a) Write a balanced equation for the
  12. Chemistry

    A sealed cylinder of gas contains nitrogen gas at 1.00 10e3 kPa pressure and a temperature of 25°C. The cylinder is left in the sun, and the temperature of the gas increases to 60.°C. What is the new pressure in the cylinder?
  13. chem help!!

    A sealed cylinder of gas contains nitrogen gas at 1.00 103 kPa pressure and a temperature of 14°C. The cylinder is left in the sun, and the temperature of the gas increases to 51°C. What is the new pressure in the cylinder?
  14. Chemistry

    Nitrogen can also be produced from sodium metal and potassium nitrate by the reaction: Na(s) +KNO3 (s) --> K2O(s) +Na2O(s) + N2(g) If we generate oxygen by the thermal decomposition of potassium chlorate: 2KClO3(s) --> 2KCl(s) +3O2(g) How many grams
  15. Chemistry check and help

    so for all the chemical formulas if there is no subscript (for the valency of the element) does it mean it is a one or do i have to find the valency on the periodic table of elements? ex. P02 the P for Phosphorus doesn't have a number does it mean it is a
  16. science

    the question says assume the valencies of hydrogen, nitrogen and carbon in the compounds are 1, 3 and 4 from this i must draw a structural formulae for hydrogen cyanide and cyanogen that are consistant with these valencies. please help H : C::: N: Does
  17. Ecnomics

    Wilpen Company, a price-setting firm, produces nearly 80 percent of all tennis balls purchased in the United States. Wilpen estimates the U.S. demand for its tennis balls by using the following linear specifications: Q= a + bP + cM + dPr Where Q is the
  18. Chemistry 22

    Table salt NaCl and sugar C12H22O11 are accidentally mixed. A 6.00 g sample is burned and 2.90 g of CO2 is produced. What was the mass percentage of the table salt mixture? Could you please show me all the way through if you can?
  19. calculus

    Can anyone walk me through the steps of solving either of these problems? 1)Determine the percentage of change of f(x)=e^0.9x at x=15 and x=30 2)For the demand function q=150(245-p^2), find E(p) and determine if the demand is elastic or inelastic (or
  20. Chem

    The actual heat of formation of MgO is -601.8 kJ/mol. Convert this to kcal/mol and calculate your % error. And list two possible sources of procedural error to account for this percentage.
  21. Chemistry

    In my problem i need to find the mass of Ag in AgNO3. I have 3.489g of AgNO3. Help please! Determine the percentage composition from the formula. PercentAg= atomicmassAg/molmassAgNO3 Then, mass Ag= 3.489 * decimal percent above.
  22. Chemistry

    A 5g mn sample was dissolved in 100ml water. If the percentage of M (At wt =55g/mol) in the sample is about 5%. What volume is needed to prepare 100ml of approximately 3.0 x 10-3 M solution Who helps for me. The right answer 6.7ml
  23. investment and real estate analysis

    A 9-year bond has a yield of 6.0% and a duration of 7.982 years. If the market yield changes by 35 basis points, what is the percentage change in the bond’s price?
  24. chemistry

    a solution of an unknown metal chloride (0.08870 g ) was treated with silver nitrate to yield AgCl ( 1.9132 g ). calculate the percentage by mass of chlorine in the unknown chloride
  25. physics

    Think of a projectile motion on an inclined table with the inclination angle α=6.The elevation angle is θ=30 and V0 is 40 cm/s. What is the percentage error (approximately) in hmax if the measured value of hmax is 5 cm? (sin6=0.1, g=10 m/s2)
  26. chemistry

    a solution of an unknown metal chloride (0.08870 g ) was treated with silver nitrate to yield AgCl ( 1.9132 g ). calculate the percentage by mass of chlorine in the unknown chloride
  27. contemporary math

    Intelligence quotients on the Stanford-Binet intelligence test are normally distributed with a mean of 100 and a standard deviation of 16. Use the 68-95-99.7 rule to find the percentage of people with the following IQs: a.) between 84 and 100 b.) below 52
  28. Physics

    An ideal gas heat engine operates in a Carnot Cycle between temperatures of 266 and 115°C. It absorbs 4250 cal per cycle at 266°C. What is its efficiency as a percentage?
  29. Physics

    An ideal gas heat engine operates in a Carnot Cycle between temperatures of 266 and 115°C. It absorbs 4250 cal per cycle at 266°C. What is its efficiency as a percentage
  30. Math

    Find the odds. A basketball player with a free throw shooting percentage of 60% gets fouled and goes to the line to shoot free throws. What are the odds in favor of her making her first shot?
  31. chemistry

    Aluminum nitrate and ammonium chloride react to form alluminum chloride, nitrogen, and water. what mass of aluminum chloride is present after 43.0 g of aluminum nitrate and 43.0 g ammonium chloride have reacted completely? Please Help
  32. chemistry

    Can someone help me with this? 1)What new element is formed if magnesium-24 is bombarded with a neutron and then ejects a proton? Write a balanced nuclear equestion for this transmutation. Is this beta decay? That's what I'm thinking, but I'm not sure. It
  33. Personal Dimensions of Education

    Which is the correct form of the verb provided to correctly complete the sentence. A high percentage of student population in the College of Health and Behavioral Sciences _____ planning to obtain an internship in the hospital while completing their
  34. chemistry

    Air consits of 21% oxygen, 78% nitrogen and 1% argon by volume. Calculate the partial pressures in Pa if total pressure is 1 atm. My teacher just converted 1atm in pa and then did 21% of that for oxygen etc etc. Can you explain why she did this, is volume
  35. Chemistry

    Which atom has the smallest valence p atomic orbital? -Carbon -Nitrogen -Sulfur Why? A. That atom has the highest electronegativity. B. That atom has the fewest number of electrons. C. That atom does not have electrons in p orbitals. D. The valence
  36. Physics

    the top sprinter in the world can reach a terminal speed of 50km/h, in 20m. Assuming the acceleration to be constant, compute the acceleration such an individual experiences, and compare it (in percentage form) to the acceleration of gravity.
  37. 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 SD=2.08. A) Children below the 30th percentile (in the bottom 30%) are in
  38. chem

    what is a liquid solution and a gaseous solution? Do you intend to ask us to name a liquid solution and a gaseous solution. One example of a liquid solution is vinegar. It is acetic acid in water. That is a solution of two liquids. An example of a gaseous
  39. Chemistryy.

    Some mole problems! Which quantity of neon may be represented by the symbol Ne? A) 1 gram B) 4 liters C) 6 x 1023 atoms D) 2 moles A sample of nitrogen containing 1.5 x 1023 molecules has the same number of molecules as a sample containing A) 1.0 mole of
  40. Geometry

    What units in the metic system would you use to measure each of the following quanities? a. distance from los angeles to new york b your waist measurement c. width of a hat d. your height The united States emitted 19.5 million t of nitrogen oxides (NO)into
  41. Chemistry- Dr.Bob!

    1. Oxygen (O2) is about 20% of our air, with about 80% nitrogen and a bunch of minor components. In Colorado Springs, where I grew up, the elevation is ~ 6500 feet and atmospheric pressure is only around 12 psi (vs. 14.7 psi at sea level). Under those
  42. chemistry

    A 1.25g sample of dry ice is added to a 750ml flask containing nitrogen gas at a temperature of 25.0 C and a pressure of 725mmHg. The dry ice is allowed to sublime (convert from solid to gas) and the mixture is allowed to return to 25.0C. What is the total
  43. chemistry

    A 1.25g sample of dry ice is added to a 750ml flask containing nitrogen gas at a temperature of 25.0 C and a pressure of 725mmHg. The dry ice is allowed to sublime (convert from solid to gas) and the mixture is allowed to return to 25.0C. What is the total
  44. Economics

    The assessed value of Patty's residential property was $200,000 in 2004. In 2006, the assessed value increased to $225,000. The property tax rate in both years was 1.2 percent. Patty earned $60,000 each year. Determine Patty’s property taxes for 2004 by
  45. Physics help?

    Nitrogen gas molecules, which have mass 4.65×10−26 kg, are striking a vertical container wall at a horizontal velocity of positive 440 m/s. 5.00×1021 molecules strike the wall each second. Assume the collisions are perfectly elastic, so each
  46. chemistry

    a tank contains 2.6 mol of nitrogen and 1.3 mol of oxygen. If 0.65 mol of oxygen were added to the tank, what effect would this have on the pressure in the tank?
  47. mass and human body

    By mass, most of human body is composed of what? nitrogen carbon water hydrogen I think the answer is water. Am I correct? http://www.madsci.org/posts/archives/may2000/958588306.An.r.html so am I correct in saying that it is water? I don't need
  48. chem

    Three of the primary components of air are carbon dioxide, nitrogen, and oxygen. In a sample containing a mixture of only these gases at exactly one atmosphere pressure, the partial pressures of carbon dioxide and ni- trogen are given as PCO2 = 0.285 torr
  49. Chem

    A 7.50g sample of aluminum is placed in 250.0 mL of 1.80 mol/L sulfuric acid. The reaction is not nearly as vigorous as expected and produces only 427 mL of gas at 27 degrees celsius and 480 kPa pressure. Calculate the percentage Yield of the reaction
  50. Chemistry

    Taking into account the "Second Law of thermodynaics", what is the maximum percentage of heat at 700 C that can be converted into electricity if the waste heat was produced as steam at 100 C? Please Give as much detail as possible instructor will not help
  51. chemistry

    A 1.252g sample containing iron dissolved and converted to Fe followed by ADDITION OF 25ML OF 0..01m K2CR2 07. THE EXCESS K2CR207 REQUIRED 6.85ML OF 0.015m SN2+. Find the percentage fe3 04 fw 213g/mol in the sample. Who helps me
  52. math

    A chartered bank is raising the interest rate on its Visa credit card from 9% to 11%. What will be the percent increase in the interest charges on a given balance? Note: Please make sure your final answer(s) are in percentage form and are accurate to 1
  53. chemistry

    A student dissolves a .726 g aspirin tablet in water and titrates the solution with .272 M NaOH are required to reach the equivalence point. Calculate the percentage of acetylsaliclic acid in the tablet. I am not really sure where to start with this. I
  54. Chemistry

    A solution contains 40.0 g of sodium chloride and 200.0 g of water. Calculate the NaCl concentration as a a) mass percentage, b) molality, c) mole fraction. I have trouble finding mole fraction. I believe I've got the other two, but I'm not 100% sure.
  55. thermo

    equal masses of ice at 0 oC, water aat 50 oC and steam at 100 oC are mixed and allowed to reach equilibrium. what will be the final temp of the mixture? and what percentage is the water and what percent will be steam??
  56. 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 minutes is %.
  57. Maths'

    What percentagge of £119.25p is £11.04p? Divide: 11.04 by 119.25. This gives you a decimal number. Move the decimal point two places to the right to turn it into a percentage. Please post your answer and we'll be glad to check it.
  58. thermo

    equal masses of ice at 0 oC, water aat 50 oC and steam at 100 oC are mixed and allowed to reach equilibrium. what will be the final temp of the mixture? and what percentage is the water and what percent will be steam??
  59. business statistics

    1.to measure how much the cost of some variable changes over time, you would use? 2.if an index number calculation over 8 years with a base value of 100 gave an index for 1993 of 110, what would be the percentage relative for 1993?
  60. maths

    A rectangular box with given dimensions length=80m, width=64m and height=48m. Has its two largest sides painted green. what percentage of the total area is painted green?
  61. Personal Finance

    Suppose you buy a two-year CD for $10,000 from First Command Bank. The interest earned at maturity is $______. Use the APY (Annual Percentage Yield) from Table 4.1. The Table says APY for this is 3.9%
  62. Chemistry

    Table salt, NaCl, and sugar C12H22O11 are accidentally mixed. A 5.50g sample is burned and 3.60g of CO2 is produced. What was the mass percentage of the table salt mixture?
  63. science

    If a radioactive isotope has a half life of 10 years and you start with 100 grams what is the fraction left, percentage left, and amount of original in grams I would like for you to explain how to do it not tell me the answer that's the question
  64. Chemistry

    Express the concentration of a 0.0510 M aqueous solution of fluoride, F-, in mass percentage and in parts per million. Assume the desnity of the solution is 1.00 g/mL Since, we're assuming the density I think that also means were assuming the volume.. but
  65. MATH

    Mabel has $35,000 to invest in a certificate of deposit for 4 years. The certificate of deposit earns interest at 4.75% compounded daily. What is the annual percentage yield to the nearest thousandth of a percent?
  66. chemistry - titration question

    please help me with this question! 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
  67. math: 68-95-99.7 rule

    suppose that prices of a certain model of new homes are normally distributed with a mean of $150,000 use the rule to find the percentage of buyers who paid: between $150,000if the standard deviation is $1200
  68. Differential Calculus

    Given that p=(2q^2-5)^2. when q=3, it is increased by 0.7%. find the appropriate percentage in p. solution dp = 2(2q^2-5) (2dq) dp = (4x(18-5)(0.7%) dp = 4(13)(0.7%) am lost from here is dp=52x0.7/100= 0.364% Responses Differential Calculus - bobpursley,
  69. Biology

    If a tall plant (TT) is crossed with a short plant (tt), what percentage of the offspring will be short?
  70. AP Calculus

    If the linearization of y= cube root of x at x=64 is used to approximate cube root of 66, what is the percentage error? a) .01% b).04% c).4% d)1% e)4%
  71. math

    The population of Town A is 60000 and town B is 70000. Find the percentage of town A as town B
  72. math

    one fourth of the students earned A's. There were 280 students. How many earned A's? I got 70 for the answer but what is the percentage for that? Would it be 70%?
  73. Chemistry

    Calculate the percentage of acetic acid used in 2.1g of acetic acid that was titrated against 0.1M NaOH
  74. chemistry

    The activation energy for a particular reaction is Ea = 14.80 kJ. What percentage of the molecules are at or above the activation energy at 500.0 K?
  75. chemistry

    an assortment of coins contains 20 pennies, 2 nickels and 6 dimes what percentage of the coins are nickels?
  76. maths

    The population of town A is 60000 and town B is 70000 find the percentage of town A as town B
  77. Math

    Sarah had got 40 out of 50 questions right. What is the percentage of questions Sarah got right? Explain and show your work.
  78. maths

    the price of a car is reduced from 1500 to 1050 by what percentage is the price reduced?
  79. Physics

    Consider hydrogen gas, H2, at 24.3°C. What percentage of hydrogen molecules have a speed within 1.00 m/s of the most probable speed?
  80. Maths Percentage

    The value of a machine depreciates every year by 10%.If the present value of the machine is Rs 54000,what was its value last year?
  81. Math

    a percentage bar graph is sometimes used like a circle graph. If the bar is 8 cm, how long is each piece?
  82. math

    A student's score is 36 and she get 100% equivalent, what is the percentage equivalent if the other student get 27 out of 36 items
  83. Maths

    Increase 472 by 25% but it has to be this way : for example increase 270 by 40% would be 270/10 and x by 4 but in this case the percentage ends with 5 so i need help
  84. Physics

    Consider hydrogen gas, H2, at 24.3°C. What percentage of hydrogen molecules have a speed within 1.00 m/s of the most probable speed?
  85. SUPER URGENT-- CHEMISTRY

    1. .0025 M tartric acid completely reacts with .0030 m of al bicarbonate if .913 l of co2 forms at 298 k with pressure of 1.4 ATM how much base used? 2. 3.1 x 10^23 molec of .0035 m hydriodic acid reacts with 25 g of magnesium bicarbonate how much carbon
  86. chemistry

    A reaction produced 55.7 mL of nitrogen gas, which was collected over water at 23oC. The measured barometric pressure was 742 torr. If the vapor pressure of water at 23oC is 21 torr, what was the mole fraction of N2 in the collected gas?
  87. Chemistry

    Write a balanced formula equation with phase indicators: Strong heating of copper(II) nitrate trihydrate produces copper (II) oxide, nitrogen dioxide, oxygen gas, and water (The part I'm confused about is how to write the molecular formula for copper (II)
  88. Manageral Economics (Economyst Only Please)

    Wilpen Company, a price-setting firm, produces nearly 80 percent of all tennis balls purchased in the United States. Wilpen estimates the U.S. demand for its tennis balls by using the following linear specifications: Q= a + bP + cM + dPr Where Q is the
  89. general chem

    Using the activity series (Table 4.5), write balanced chemical equations for the following reactions. If no reaction occurs, simply write NR. (a) Nickel metal is added to a solution of copper (II) nitrate; (b) a solution of zinc nitrate is added to a
  90. chemisrty

    What is the total pressure of the gas produced in the burette if it contains nitrogen gas whose pressure is 1.5 atm, oxygen gas whose pressure is 1.6 atm and water vapour with a pressure of 1.3 atm.
  91. Science

    Which of the following best describes the dependent variable in an experiment? A- the variable that is measured B- the variable that is manipulated C- the variable that you can see D- the variable that is most common (My guess is A) Photosynthesis is the
  92. stats

    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 means are
  93. Probability and Statisics

    Suppose that 20% of the adult women in the United States dye or highlight their hair. We would like to know the probability that a SRS of size 200 would come within plus or minus 3 percentage points of this true value. In other words, find probability that
  94. math (pre-calc)

    Analyzing a Stock. The beta, B of a stock represents the relative risk of a stock compared with a market basket of stocks, such as Standard and poor's 500 Index of stocks. Beta is computed by finding the slope of the line of best fit between the rate of
  95. Chemistry

    1. A graduate measured out a 100. mL hard water sample and titrated it with 37.6 mL of 0.0100 M EDTA solution for a total hardness endpoint, and 29.3 mL of 0.0100 M EDTA solution for a calcium endpoint. Calculate the molarity with respect to magnesium and
  96. Science

    Milk of magnesia has the chemical formula Mg(OH)2. what is the mass of 3.2 moles of milk of magnesia? The molar mass of magnesium is 24.3 grams per mole. The molar mass of hydrogen is 1.0 grams per mole. The molar mass of oxygen is 16.0 grams per mole. A.
  97. Physics PLEASE HELP

    Nitrogen gas molecules, which have mass 4.65×10−26 kg, are striking a vertical container wall at a horizontal velocity of positive 440 m/s. 5.00×1021 molecules strike the wall each second. Assume the collisions are perfectly elastic, so each
  98. chemistry

    Dinitrogen tetroxide decomposes to form nitrogen dioxide in a second order reaction: N2O4(g)-> 2NO2(g) At 400K, the rate constant for this reaction has been measured to be 2.9x10^8 L/mol*s.suppose 0.222 mol of N2O4(g) is placed in a sealed 41.7L
  99. Chemistry

    NOCL(g) decomposes to from nitrogen monoxide gas and chlorine gas. The equation is 2NOCL ----> 2NO +Cl2 At a certain temperature the equilibrium constant is 1.60 x 10^-6. Calculate the equilibrium concentrations of all gases if 0.800 moles of NOCL are
  100. proofread chemistry

    write the formulas for the following compounds Sodium chlorate i put NaCl Lead (II) phosphate i put Pb2P For Magnesium hydrogen carbonate i had no clue! then it stats state the number of electrons lost or gained in forming each of these Ions. I didn't