1. chemistry

    A strip of aluminium of mass 40.7g is dropped into a beaker of dilute hydrochloric acid. Calculate the work done (in J) on the surrounding atmosphere (1atm pressure, 26.1oC ) by the evolution of hydrogen in the subsequent reaction. State any assumptions
  2. Statics

    For each of the following, state (using symbols) the null and alternative hypotheses. a. Is the mean IQ of a sample of 60 children significantly below the national average of 100? b. Is the proportion of men in the class more than that expected by chance?
  3. Chemistry

    A weather balloon is inflated to a volume of 26.2 L at a pressure of 755 mmHg and a temperature of 32.5 ∘C. The balloon rises in the atmosphere to an altitude where the pressure is 360. mmHg and the temperature is -13.5 ∘C. Assuming the balloon
  4. Chemistry

    A weather balloon is inflated to a volume of 29.9 L at a pressure of 755 mmHg and a temperature of 33.0 ∘C. The balloon rises in the atmosphere to an altitude where the pressure is 385 mmHg and the temperature is -16.2 ∘C. Assuming the balloon
  5. chemistry help plz

    Le chatelier's principle? co(g)+cl2(g)=cocl2(g)is reversible and ,after a certain amount of time ,will reach equilibrium.Explain,using Le chatelier's principle,what effect: 1)increasing the pressure (at constant temperature) 2)increasing the temperature
  6. CHEM

    The vapor pressure of pure water at 25 °C is 23.8 torr. Determine the vapor pressure (torr) of water at 25 °C above a solution prepared by dissolving 35 g of urea (a nonvolatile, non-electrolyte, MW = 60.0 g/mol) in 75 g of water. where have i made a
  7. Fluid Mechanics

    A circular disc having a diameter of 125cm is immersed in water so that the distance of its perimeter measured vertically below the water surface varies between 60cm and 150cm. Find the total force due to the water acting on one side of the lamina, and the
  8. Fluid Mechanics

    A circular disc having a diameter of 125cm is immersed in water so that the distance of its perimeter measured vertically below the water surface varies between 60cm and 150cm. Find the total force due to the water acting on one side of the lamina, and the
  9. Fluid Mechanics

    A circular disc having a diameter of 125cm is immersed in water so that the distance of its perimeter measured vertically below the water surface varies between 60cm and 150cm. Find the total force due to the water acting on one side of the lamina, and the
  10. Fluid Mechanics

    Water at 600F flows steadily through a horizontal circular divergent duct and discharges into the atmosphere as shown. A manometer with a fluid of SG=2.0 is placed between the two cross-sections with diameters D1 = 0.5 ft and D2 = 0.7 ft. Assuming inviscid
  11. Fluid Mechanics

    A circular disc having a diameter of 125cm is immersed in water so that the distance of its perimeter measured vertically below the water surface varies between 60cm and 150cm. Find the total force due to the water acting on one side of the lamina, and the
  12. Fluid Mechanics

    A circular disc having a diameter of 125cm is immersed in water so that the distance of its perimeter measured vertically below the water surface varies between 60cm and 150cm. Find the total force due to the water acting on one side of the lamina, and the
  13. physics

    a cylinder of diameter 1cm at 30degree celcius is to slid into a hole on a steel plate. the hole has a diameter of 0.9997 cm at 30 degree celcius. to what temperature must be the plate be heated when steel has the alpha 1.1X10^-5/degree celcius
  14. Chemistry 101

    A 16 Gauge wire has a diameter of 0.0508 inch. Calculate the length in meters of a 5.00 pound spool of this wire. The density of copper is 8.92g cm^-3
  15. Physics - Buoyancy

    A sphere of mass of m = 1.69 kg is first placed directly on the plate of an electronic scale. The scale shows 16.58 N as the weight of the object. A large beaker containing a liquid with a density of 783 kg/m^3 is then placed on the scale and the scale is
  16. Physics

    A uniform rod of weight 300N and 2m long is hinged to the floor at one end so that it can rotate in the vertical plane. The other end of the rod is tied to a point on the ceiling vertically above the floor hinge by means of a rope 2.5m long. The vertical
  17. Biomechanics

    Person A: Weight: 1200 N Net Impulse for counter movement jump: 240 Ns Person B: Weight: 800 N Net Impulse for counter movement jump: 160 Ns 1) Which person jumped highest? 2)What was kinetic energy of each person right before they left the ground? 3)What
  18. Physics

    The system shown in the figure is in equilibrium. A 15 kg mass is on the table. A string attached to the knot and the ceiling makes an angle of 54◦ with the horizontal. The coefficient of the static friction between the 15 kg mass and the
  19. Chemistry

    An excess of zinc metal is added to 50.0 mL of a 0.100 M AgNO3 solution in a constant-pressure calorimeter. Assuming that the density of the solution is the same as for water, calculate the mass of the solution.
  20. chemistry

    For a skydiver jumping out of a plane at an altitude of 1 km, what would be the concentration of oxygen in his (or her) blood knowing that air pressure at 1 km drops to 89,874 Pa? Assume ideal behavior of gases, normal breathing, 25 °C and constant air
  21. Statistics

    Are my answers here correct ? Research questions for z test, t test for independent samples and t test for dependent samples : z test: "An investigator is interested in finding out whether the particular sample of college students is similar to or
  22. Statistics Help !!

    Are my answers here correct ? Research questions for z test, t test for independent samples and t test for dependent samples : z test: "An investigator is interested in finding out whether the particular sample of college students is similar to or
  23. Statistics Help !!!!

    Are my answers here correct ? Research questions for z test, t test for independent samples and t test for dependent samples : z test: "An investigator is interested in finding out whether the particular sample of college students is similar to or
  24. physics

    Object A has a gravitational potential energy of 24 joules when it rests on a shelf 5 m above the ground. Object B has a mass that is three times the mass of Object A. What would be the gravitational potential energy of object B when it rests on a shelf 10
  25. chem

    Forty miles above the earth's surface the temperature is 250 K and the pressure is only 0.20 mm Hg. What is the density of air (in grams per liter) at this altitude? (Assume the molar mass of air is 28.96 g/mol.) PV=nRT n/V= molar desity= P/RT mass
  26. Physics

    A primitive diving bell consists of a cylindrical tank with one end open and one end closed. The tank is lowered into a freshwater lake, open end downward. Water rises into the tank, compressing the trapped air, whose temperature remains constant during
  27. chemistry

    For the reaction below, KP = 1.6 × 106 at 400.0 °C. HCHO2( g ) <--> CO( g ) + H2O( g ) A mixture of CO( g ) and H2O(l ) was prepared in a 2.00 L reaction vessel at 25 °C in which the pressure of CO was 0.177 atm. The mixture also contained 0.391 g
  28. math

    Fresh Grapes contain 80 percent water by weight and 20 percent juice, whereas dried grapes contain 15 percent water by weight with the rest juice. How many punds of dried grapes are needed to yield the same amount of juice as 34 pounds of fresh grapes?
  29. chemistry

    what is the molar mass of a gas if 26.0L of the gas has a mass of 43.6g at 1.10 atm and 10.0 C?
  30. chem

    A flask is charged with 1.596 atm of N2O4(g) and 1.008 atm of NO2(g) at 25°C, and the following equilibrium is achieved. N2O4(g)-> 2 NO2(g) After equilibrium is reached, the partial pressure of NO2 is 0.504 atm. (a) What is the equilibrium partial
  31. Statistics

    Explaining confidence. A student reads that a 95% confidence interval for the mean ideal weight given by adult American women is 140 ± 1.4 pounds. Asked to explain the meaning of this interval, the student says, “95% of all adult American women would
  32. biochemistry

    please explain how to get these answers (answers provided): 1. If this cell were a muscle cell (myocyte), how many molecules of actin could it hold? (Assume the cell is spherical and no other cellular components are present; actin molecules are spherical,
  33. physics

    a jet pilot takes his aircraft in a vertical loop. a) if the jet is moving at a speed of 2000 km/h at the lowest point of the loop, determine the minimum radius of the circle so that the centripetal acceleration at the lowest point does not exceed 6.0g's
  34. chemistry

    Find the false statement(s) about the thermochemistry experiment in which nitric acid is reacted with sodium hydroxide, and the enthalpy of the reaction is measured using an ice calorimeter. i. Regardless of which strong acid and strong base are used for
  35. Chemistry - Science (Dr. Bob222)

    Liquid chloroform (CHCl3) is placed in a closed container and allowed to equilibrate with chloroform vapor. With the temperature held constant, additional chloroform is introduced into the system, and the vapor-liquid equilibrium is reestablished.
  36. differential calculus

    ADIABATIC EXPANSION when a certain polyatomic gas undergoes adiabatic expansion,its pressure p and volume V satisfy the equation pV^1.3 =k,where k is constant.Find the relationship between the related rates dp/dt and dV/dt. this is a problem of related
  37. physics

    Oxygen gas having a volume of 784 cm3 at 23.3°C and 1.03 x 105 Pa expands until its volume is 1170 cm3 and its pressure is 1.07 x 105 Pa. Find (a) the number of moles of oxygen present and (b) the final temperature of the sample. (Unit kelvin, K, for part
  38. chemistry

    Imagine that 25.0 of ice at -3.0C is placed in a container holding water vapor at temperature of 120.0C . After a certain amount of time, the container has expanded slightly, but holds only water vapor at 110.0C. what is the final volume of the container?
  39. chemistry

    Imagine that 25.0 of ice at -3.0C is placed in a container holding water vapor at temperature of 120.0C . After a certain amount of time, the container has expanded slightly, but holds only water vapor at 110.0C. what is the final volume of the container?
  40. Health

    Describe how respecting yourself and respecting your values can improve your self-esteem. A: If you respect yourself, you will be proud of yourself. Therefore, your self-esteem will rise. If you respect your values, you will less likely allow others to
  41. Physics

    The main water line enters a house on the first floor. The line has a gauge pressure of 1.70 105 Pa. (a) A faucet on the second floor, 6.5 m above the first floor, is turned off. What is the gauge pressure at this faucet? (b) How high could a faucet be
  42. chemistry

    osmotic pressure of a solution containing 7g of protein in 100ml of solution is 20mmhg at37celsius calculate molecular mass of the protein
  43. Chem

    The vapor pressure of CCl3F at 300K is 856torr. If 11.5g of CCl3F is enclosed in a 1L container, Will any liquid be present? If so, what mass of liquid?
  44. Chem

    A mass of 0.4 g of hydrogen (H2) and 3.2 g of helium (He) are mixed in a rigid 500 mL container. What is the partial pressure of helium when the container is cooled to 77 K ?
  45. physic II

    Two liters of a perfect gas are at 0 degree C and 1 atm.If the gas is nitrogen, N2. Determine the number of moles? Determine the mass of the gas?
  46. chemistry-URGENT!!

    A sample of ammonina gas at 65.5 degrees celsius and 524 torr has avolume of 15.31 L. What is it's volume at -15.8 degrees celsius and its pressure is 524 torr?
  47. Probabability

    You are in charge of quality control on a line which fills bottles of soda. The desired gross weight for a 2 liter bottle of soda is 2,160 grams. At the end of each shift you select 12 bottles at random and weigh them. After one month, the overall average
  48. Physics

    The leg and cast in the figure below weigh 280 N, with the center of mass as indicated by the blue arrow in the diagram. The counterbalance w1 weighs 130 N. Determine the weight w2 and the angle á needed so that no force is exerted on the hip joint by the
  49. physics

    The leg and cast in the figure below weigh 210 N, with the center of mass as indicated by the blue arrow in the diagram. The counterbalance w1 weighs 125 N. Determine the weight w2 and the angle á needed so that no force is exerted on the hip joint by the
  50. general physics

    Neutron stars consist only of neutrons and have unbelievably high densities. A typical mass and radius for a neutron star might be 6.3 x 1028 kg and 1.6 x 103 m. (a) Find the density of such a star. (b) If a dime (V = 2.0 x 10-7 m3) were made from this
  51. physics

    The leg and cast weigh 200 N, with the center of mass as indicated by the blue arrow in the diagram. The counterbalance w1 weighs 105 N. Determine the weight w2 and the angle α needed so that no force is exerted on the hip joint by the leg plus cast.
  52. Physics

    Exploration 2: the Effect of Mass on Gas Behavior Procedure 1. Set the temperature at 500 K. Maintain this temperature throughout this Exploration. 2. Select Hydrogen gas from the list box. Record the most probable particle speed and the average particle
  53. Overweight/Normal-weight

    Compared to overweight people, normal-weight people are ___ likely to engage in eating binges, and ___ likely to experience emotional problems. a. less...more b. less...less c. more...less d. about equally...about equally i chose answer B. because if they
  54. English-Room 101 speech

    I have to come up with a speech about what I feel should go into room 101. Room 101 is a british tv programme, which came from a book. It's basically when people give reasons of what they don't like. The presenter decides, what goes into room 101. I am
  55. Chemistry

    The vapor pressure of CCl3F at 300 K is 856 torr. If 11.5 g of CCl3F is enclosed in a 1.0 L container, will any liquid be present? If so, what mass of liquid?
  56. Chemistry II

    what is the molar mass of a gaseous organic compound with a density of 3.38 g/L at 40oC and a pressure of 1.97 atm? Ok, I am little confused because I am not sure of where to plug in the density and the atm?
  57. Chemistry

    A solution containing 26.40 mg of an unknown protein per 22.5 mL solution was found to have an osmotic pressure of 3.95 torr at 21 C. What is the molar mass of the protein?
  58. chemistry

    Consider a 675-mL container at 499 °C in which the pressure of nitrogen is 1.98x106 Pa. a) What mass of nitrogen (in g) is present in this container? b) How many molecules is this?
  59. chemistry

    A solution containing 26.05 mg of an unknown protein per 23.5 mL solution was found to have an osmotic pressure of 3.75 torr at 44 C. What is the molar mass of the protein?
  60. density and pressure

    calculate the mass of air in a room measuring 5m*8m*10m if the density of air is 1.3kg/m cube
  61. physics

    A cube of edge 2cm and mass 10g is placed on the surface of a table. What is the pressure exerted by the cube on the table.
  62. chemistry

    Hello, a few questions: Thanks so much! 1. The heat capacities of titanium and water are 0.522 J g-1 K-1 and 4.184 J g-1 K-1, respectively. What is the final temperature of the titanium-water mixture if a 175.0-g sample of titanium, initially at 90.0oC, is
  63. 8th grade algebra

    Can you clarify when to half the diameter when finding volume of cylinder? I had the following problem: 1. Picture of cylinder with base of 48cm (no dotted lines) and height of 7cm. I thought i would solve by using V = 3.14(24)^2 (7) = 12,660.5 cubic
  64. Chemistry

    Okay, I have some confusion on a lab question for chemistry. The question was if you were preforming a microscale extraction of a 0.2 g of benzoic acid/fluorenone mixture (About 6 mL of dichloromethane and 2 mL of NaOH were added through out this
  65. Math

    You went to lunch with your friend and the bill is $19.00 your lunch is $3.00 more than your friends. How much was your friends lunch? f + 3 = 19; $8.00 3f + 2 = 19; $8.00 2f + 3 = 19; $8.00 2f - 3 = 19; $8.00 Mark weighs 74 pounds. together he and his
  66. physics

    The deepest place in the ocean is the Marianas Trench in the western Pacific Ocean, which is over 11.0 km deep. On January 23, 1960, the research sub Trieste went to a depth of 10.915 km, nearly to the bottom of the trench. This still is the deepest dive
  67. Science

    How does accuracy differ from precision? Accuracy is how close a measurement is to a generally accepted value. Precision is how many digits the measurement is. My weight is 160 lbs, generally accepted as true. My to scales recoreded my weight as 164lbs,
  68. science

    A bicycle tire is filled with air to a pressure of 6.80 atm and a temperature of 19 degrees Celsius. Riding the bike on asphalt on a hot day increases the temperature of the tire to 58 degrees Celsius. The volume of the tire increases by 4.0%.What is the
  69. chemistry; Lab questions help=)

    was hoping someone can help me check if these answers make sense for a silver copper alloy lab. 3. Why don’t you have to weigh the sodium chloride on a sensitive balance? This one I am not sure about, It is because an excess of NaCl is needed to make
  70. Algebra 2

    The force needed to overcome friction and drag a person across the floor depends on the person's weight. Manuel Dexterity can drag Gil O' Teen across the floor by pulling with a force of 51 pounds. Gil's brother, Nick who weighs twice as much can be
  71. science

    a man with a mass of 90,6 kg walks to the back of a train at a velocity of 1m/s while the train moves at a constant velocity of 36km/h in a easterly direction. what is the weight of the man
  72. Physics

    A body of mass 10kg falls from a height of 5m above the ground what is the kinetic energy of the body just before its strike the ground. Weight loss of energy and take g=10m/s^2.
  73. Chemistry

    When 100.0 g of an unknown nonelectrolyte is dissolved in 500.0 g of benzene, C6H6, the solution boils at 82.9°C. Calculate the molecular weight (molar mass) of the unknown material. Kb for benzene is 2.53°C/m and the boiling point of pure benzene is
  74. physics

    1. Henry gets into an elevator on the 50th floor of a building and it begins moving at t = 2s. The figure shows the his apparent weight over the next 10 s. a. Is the elevator’s initial direction up or down? Explain clearly how you arrived at this
  75. chemistry

    water has a molar mass weight of 18 grams that's 18 grams per mole you drink a 2 liter bottle of water everyday and you are such a smarty that you you know that 1mlof h2o weighs 1 gram can you tell me how many moles of water you consume a day
  76. 11th grade Chemistry 1

    If your weight is 120 pounds and your mass is 54 kilograms, how would those values change if you were on the moon? The gravitational force on the moon is 1/6 the gravitational force on Earth.
  77. Chemistry

    If 150.0 g of butane (C4H10) gas are burned, how many grams of carbon dioxide gas will be produced? Report your answer to the nearest whole number and do not include units in your answer. Do not use scientific notation for your answer. This is a
  78. PHYSICS

    assume you have a mass of 100 kg on earth. on the moon, where the gravitation of the moon is 1/6 gravitation of the earth, what is your mass on the moon and what is your weight on the moon
  79. Physics

    A nonuniform cylinder (radius = 0.14 m, center-of-mass rotational inertia = 2.21×10^-2 kg·m^2, mass = 1.36 kg) starts from rest and rolls without slipping down a plane with an angle of inclination of 24.0 degrees. How long does it take to travel 1.72 m
  80. Chemistry

    You have 4.271 x 102 mL of oxygen gas (O2) at 7.656 x 102 mm of Hg and 78 oC. What is the mass of the sample in milligrams? What is the ratio of effusion rates for a light gas, such as HF, to a heavy gas, such as UF4?
  81. mass transfer

    A catalytic reactor in an automobile is used to convert gas A to gas B where 3 mol of gas A diffuse to the catalyst for every 1 mol of B diffusing away at a distance (mm). the reaction balance is shown as follows: 3A-B
  82. calculus help

    A drinking cup is made in the shape of a right circular cylinder. for a fixed volume, we wish to make the total material used, the circular bottom and the cylindrical side, as small as possible. Find the ratio of the height to the diameter that minimizes
  83. Math

    If the radius of a right circular cylinder is tripled and its altitude is cut in half, then the ratio of the volume of the original cylinder to the volume of the altered cylinder is?
  84. Algebra

    the base of a cylinder is a right triangle topped by a 60 degrees sector of a circle, as shown. if the dimensions are in meters and the height of the cylinder is 8 meters, what is the volume of the cylinder?
  85. Physics

    A block with mass M rests on a frictionless surface and is connected to a horizontal spring of force constant k, the other end of which is attached to a wall. A second block with mass m rests on top of the first block. The coefficient of static friction
  86. chemistry

    3. Find the empirical formula for a compound that consists of aluminum and chlorine in which the aluminum is 20.2 % by mass. 4. A sample contains 71.65% CL, 24.27% C nad 4.07% H. the molecular weight is known to be 98.96 g/mol. What are the empirical and
  87. Chemistry

    an aqueous solution contains 1.00g/L of a derivative of detergent lauryl alcohol.the osmotic pressure of this solution at 25 °c is 2.0 x 10³ Nm-², what is the molar mass of the detergent.
  88. CHEMISTRY

    1).What is the pressure in a 1.5 L vessel containing 0.25 moles of O2 if the temperature is 37 degrees celcius? 2).The molar mass of MgCO3 is 84g/mole. How many moles are in 12.60g of MgCO3?
  89. Chemistry

    The water vapor pressure at 25 degrees celsius is 23.76 torr. If 1.25 grams of water is enclosed in a 1.5 L container, will any liquid be present? If so, what mass of liquid?
  90. physics

    the mass of a brick is 2.5 kg. its dimensions are 10cmx5cmx2cm. find the pressure of the brick exerts on the ground if it is resting on a. 10cmx5cm base and b. 5cmx2cm base
  91. Science

    There are two objects of the same size.However, one object is made of wood, and the other object is made of plastic. Which of the following properties of the objects will be the same? A)mass B)texture C)volume D)weight Thanks!!!
  92. Science

    The force of gravity of objects on the moon is approximately one-sixth of their value on Earth. Joe's weight on the moon is 124 N. What will Joe's mass on Earth be?
  93. Chem

    Calculate the percent yield of eugenol obtained considering the fact that clove oil is approximately 16-19 % clove by weight of cloves. isolated eugenol=061g purity of eugenol in clove oil=99.6% (based on clove oil gas chromatograph) Estimate the % yeild
  94. Chemistry

    A 12.0L sample of a as at a constant pressure of 608 mm Hg was heated from 40 degrees celsius to 60 degrees celsius. What volume does the gas now occupy? would I multiply 608 by 12 and then divide by the degrees celsius?
  95. science

    What would be the volume of hydrogen(2g/mol) needed in a balloon to lift a 50kg man? Assume that the temperature is 300K pressure is 1atm and air has average mass of 29 g/mol and that both gases behave ideally.
  96. chemistry

    A solution prepared by adding 0.17 g of a polymer to 0.6 L of toluene (methylbenzene, a common solvent) showed an osmotic pressure of 0.808 Torr at 21â—¦C. What is the molar mass of the polymer? Answer in units of g/mol.
  97. chemistry

    Sodium carbonate, Na2CO3(s), can be prepared by heating sodium bicarbonate, NaHCO3(s). 2NaHCO3(s) Na2CO3(s) + CO2(g) + H2O(g) Kp = 0.23 at 100ºC If a sample of NaHCO3 is placed in an evacuated flask and allowed to achieve equilibrium at 100ºC, what will
  98. AP Chemistry

    In a fit of boredom, a chemistry teaching assistant swallows a small piece of solid dry ice (CO2). The 8.9 g of dry ice are converted very quickly into gas at 311 K. Assuming the TA’s stomach has a volume of 1.5 L, what pressure is exerted on his
  99. Chemistry

    heptane and water do not mix, and heptane has a lower density (0.684g/mL) than water (1.00g/mL). A 100mL graduate cylinder with an inside diameter of 3.10 cm contains 39.90g of heptane and 34.00g of water. What is the combined height of the two liquid
  100. physics:(

    The weight of a book on an inclined plane can be resolved into two vector components, one along the plane, the other perpendicular to it. At what incline angle are the components equal? I was kind of thinking 45 degress?????? At what incline angle is the