1. physics

    An object has a charge of −2.4 ìC. How many electrons must be removed so that the charge becomes +2.8 ìC
  2. ochemistry

    How many pi-electrons are in the thiazoline ring of thiamine hydrochloride? of thiamine?
  3. Science

    Two pellets, each with a charge of 1.5 microcoulomb (1.5×10−6 C ), are located 2.8 cm (2.8×10−2 m ) apart. Part A Find the electric force between them.Part B What would be the mass of an object that would experience this same force in Earth's
  4. Physics

    1) Find the magnitude of the gravitational force a 68.6 kg person would experience while standing on the surface of Earth with a mass of 5.98 × 10 24 kg and a radius of 6.37 × 10 6 m. The universal gravitational constant is 6.673 × 10 −11 N · m2
  5. physics

    Steel expands 11 parts in a million for each 1 degree C change. Consider a 40,000 km steel pipe that forms a ring to fit snugly all around the circumference of the Earth. Suppose people along its length breathe on it so as to raise its temperature 0.80
  6. physics

    Steel expands 11 parts in a million for each 1 degree C change. Consider a 40,000 km steel pipe that forms a ring to fit snugly all around the circumference of the Earth. Suppose people along its length breathe on it so as to raise its temperature 0.80
  7. physics

    Steel expands 11 parts in a million for each 1 degree C change. Consider a 40,000 km steel pipe that forms a ring to fit snugly all around the circumference of the Earth. Suppose people along its length breathe on it so as to raise its temperature 0.80
  8. Math

    I need some help on figureing out how to answer these problems please i have never done this type of math before thank you Find the discount and total to be paid for each of the following: Amount Terms When Paid Discount Total $2.000 3/30 22 days $400 2/10
  9. math

    An object of mass 100g is thrown vertically upward from a point 60cm above the earths surface with an initial velocity of 150cm/sec. It rises briefly and then falls vertically to the earth, all of which time it is acted on by air resistance that is
  10. Chemistry

    what is the balanced net ionic equation for the reaction of ascorbic acid with triiodide ion C6H8O6 ==> C6H6O6+ 2H^+ + 2e 2e + I3^- ==> 3I^- ==================== These are to two half equations. Add them and cancel the electrons.
  11. science

    What is true about the element francium(Fr,atomic number 87)? Choose all that apply. a. it has 7 valence electrons b. it is likely to form ionic bonds c. it is a nonmetal d. it is in period 7 e. it is a metal Is the answer a,d,e?
  12. Chemistry

    In which orbital does an electron in a phosphorus atom experience the greatest effective nuclear charge? a. 1s b. 2s c. 2p d. 3s e. 3p I originally thought 3p, since those are the outer electrons, but that was marked wrong. Why is it not 3p? Is the right
  13. nuclear engineering

    Determine the amount of energy required (in MeV) to dissociate the following elements into component parts (protons, neutrons and electrons) • Hydrogen • Deuterium • Tritium
  14. Chemistry

    What assures that there is no charge build up in a voltaic cell as oxidation and reduction occur? one of the half cells the electrolyte solutions*** the moving electrons the salt bridge
  15. chemisry

    A solid metal is described as having "AN ARRAY OF POSITIVE IONS IN A SEA OF ELECTRONS". Write down the electronic structure of a magnesium atom and use it to explain what this PHRASE means? can you please help me with this question thanks
  16. General Chemistry

    lectron configuration of a neutral atom is 1s22s22p63s23p2.      a) Draw the orbital diagram.      b) Write a complete set of quantum numbers for each of the electrons.      c) Name the element.
  17. Science

    In a wet type of voltaic cell, what is the electrolyte? a. a bridge made of salt b. a copper strip c. an acidic liquid d. a spontaneous flow of electrons A believe the answer is C
  18. Science

    The diagram below shows a process in Earth's crust. Which of the following statements best describes the process in the diagram. A Converging plates from Mountains B Converging plates from Volcanoes C Diverging plates form Mountains D Diverging plates form
  19. Physics

    The moon rotates about its axis every 27.3 days and orbits the earth every 27.3 days. A) what is the moment of inertia with respect to its axis? B) What is the moment of inertia with respect to the earth? C) What is the moons angular momentum with respect
  20. Science

    Please help me with my sciene? Which type of eclipse would you expect to see if the moon passes directly between Earth and the sun? (1 point) a solar eclipse a lunar eclipse a total lunar eclipse a penumbra 2. Which of the following statements about a
  21. Math Probability

    Super stumped... Help please. The average distance geese fly south in the winter is approximately 380 miles with a standard deviation of 60 miles. Assuming that the distances are normally distributed, find the probability that a randomly selected goose
  22. science

    how is the equator similar to the prime meridian A. both the prime meridian and equator are lines that divide earth into norther and southern hemispheres B. both the prime meridian and equator are imaginary base lines from which locations of earth can be
  23. physics

    the first active volcano observed outside the earth was discovered in 1979 on Io, one of the moons of jupiter. the volcano was observed to be ejecting material to a height of about 2.00x10^5m. given that the acceleration of gravity on Io is 1.80 m/s^2,
  24. science

    An atom of sodium-23 (atomic number = 11) has a positive charge of +1. Given this information, how many electrons does it have? How many protons and neutrons does this atom have?
  25. Science

    In an atom, electrons ____. are located in the nucleus are paired with neutrons are located in the electron cloud are always in the same place
  26. physics

    If a more complicated atom has two energy levels for its electrons at (-15) eV and (-30.1) eV, what is the wavelength of the photon (in nm) that is emitted when an electron transitions between these two levels?
  27. chemistry

    an unknown element, X, reacts with chlorine to form an ionic compound XC12, if the X ion has 18 electrons, the element X is what?
  28. Physical Science

    true or false in an atom, negatively charged electrons surround a positively charged nucleus
  29. Physics

    Problem 22.2 2*10^ 13 electrons flow through a transistor in 1.0 ms. Part A - What is the current through the transistor? Express your answer using two significant figures. in mA
  30. electrons in atoms

    What is the wavelength of the emitted photon, when the electron in the hydrogen atom makes a transition from the ni = 5 state to the nf = 3 state?
  31. Physics

    Problem 22.2 2 *10 ^13 electrons flow through a transistor in 1.0 ms. Part A - What is the current through the transistor? Express your answer using two significant figures.
  32. Micoud secondary

    determine the number of electrons required to deposit 6.4g of copper from an aqueous solution of copper II sulphate
  33. Chemistry

    For the balanced redox reaction 2 Al(s) + 3 Br2(g) → Al2Br6(s), determine the number of electrons transferred in the overall reaction.
  34. Physics

    If enough energy were supplied to a diamond would that allow some of its electrons to transition to a higher energy band and therefore conduct electricity? Just curious.
  35. AP Chemistry

    The principal quantum number of the electrons that are lost when tungsten forms a cation is ? Tungsten is a transition metal.
  36. Chemistry Help Please!

    At most, how many 4d electrons can an atom have? Of these what is the maximum number that can have ms= -1/2? A 5f electron has what value of quantum number l? What values of ml may it have? Also please explain how you got the answers so I can understand?
  37. Chemistry

    Are binary compounds ionic or covalent? If they are covalent, I thought they don't form bonds that way, since they share electrons.
  38. Physics

    To what voltages must we accelerate electrons (as in an electron microscope, for example) if we wish to resolve; a) a virus of diameter 12 nm , b) an atom of 0.12 nm, c) a proton of diameter 1.2 fm?
  39. physics

    what effect did scientists originally think that the intensity of light shining on a photosensitive surface would have on electrons ejected from that surface?
  40. 9th grade

    would you expect the following atom to gain or lose electrons when forming ions? what ion is the most likey? The atom is In how would i do this?
  41. Physics

    How many electrons must be removed from an object to leave it with a charge of 2.0 x 10 exp-10C? This is a small though not neglible static charge.
  42. chemistry

    The electron configuration of the outermost electrons of the halogen group is: a)ns2np7 b)ns1 c)ns2np5 d)ns2np6(n-1)d7 e)ns2np6
  43. Physics

    Problem 22.2 2*10^ 13 electrons flow through a transistor in 1.0 ms. Part A - What is the current through the transistor? Express your answer using two significant figures. in mA
  44. Physics

    You have a neutral balloon. What is its charge after 12000 electrons have been removed from it? The elemental charge is 1.6 × 10−19 C. Answer in units of µC.
  45. Chemistry

    Consider the last electron in B: Values for n,l,and ml of 2,0,0 cannot be used. Why not? so is this the same answer as lithium. The ground stat cant have l=2 since it has no p electrons? Are values of 3,0, 0 allowed? Why or why not? I would say no for the
  46. chemistry

    In terms of chemical bonds and electrons, what kinds of changes occur between atoms when substances undego chemical reactions?
  47. Science

    hi i have a science exam on tuesday and i don't understand this question and really need some help. How many electrons, protons and neutrons in the following: a)Br1- b)Be2+ c)Ne d)P1- e)Fe
  48. physics

    If a proton were traveling the same speed as electrons in a TV picture tube (about 7.2 107 m/s), what would its de Broglie wavelength be? The mass of a proton is 1.67 10-27 kg.
  49. AP Chemistry

    The principal quantum number of the electrons that are lost when tungsten forms a cation is ? Tungsten is a transition metal.
  50. Walk Two Moons

    Has anyone read the story walk two moons? If so, please help. where does Sal BEGIN to realize that her mother is really not returning? A) Lake Michigan B) Madison Wisconsin C) Pipestone Minnesota *** D) Sioux Falls, South Dakota please help, I've read the
  51. physics

    1. what happens to the field strength when you halve the distance between two charges? 2. A positive charge of 3.5 uC is located in an electric field of intensity 3.00 N/C directed toward the south. Find the magnitude and the direction of the force on the
  52. AP Physics C

    An earth satellite, the mass of which is 1000 kg, is in a circular orbit 1000 km above the surface of the earth. It is desired to transfer it to a circular orbit 1500 km above the surface. The amount of work that must be done to accomplish this is A. 3.43
  53. Physics

    You are traveling on an airplane. The velocity of the plane with respect to the air is 110.0 m/s due east. The velocity of the air with respect to the ground is 39.0 m/s at an angle of 30° west of due north. 1) What is the speed of the plane with respect
  54. physics

    You are traveling on an airplane. The velocity of the plane with respect to the air is 180 m/s due east. The velocity of the air with respect to the ground is 40 m/s at an angle of 30° west of due north. 1)What is the speed of the plane with respect to
  55. Physics

    You are traveling on an airplane. The velocity of the plane with respect to the air is 140 m/s due east. The velocity of the air with respect to the ground is 34 m/s at an angle of 30° west of due north. 1)What is the speed of the plane with respect to
  56. Physics HELP!!!

    A certain satellite has a kinetic energy of 7.5 billion joules at perigee (closest to Earth) and 3.5 billion joules at apogee (farthest from Earth). As the satellite travels from apogee to perigee, how much work does the gravitational force do on it? Does
  57. math

    Sam and markus are standing on level ground 100m apart. A large tree is due north of markus and on a bearing of 65degrees from sam. The top of the tree appears at an angle of elevation of 25degrees to sam and 15degrees to markus. Find the height of the
  58. Maths

    A straight river flows at a speed of 20km/h. A boater starts at the south shore and heads in ths direction of 70degrees from the shore. The boat has a speed of 20km/h in still water. Find the true speed and direction of the boat.
  59. physics

    In 1956, Frank Lloyd Wright proposed the construction of a mile-high building in Chicago. Suppose the building had been constructed. Ignoring Earth's rotation, find the change in your weight if you were to ride an elevator from the street level, where you
  60. Physics

    The first stage of a space vehicle consumed fuel and oxidizer at the rate of 1.65 104 kg/s with an exhaust speed of 2.55 103 m/s. (a) Calculate the thrust produced by this engine. (b) Find the acceleration the vehicle had just as it lifted off the launch
  61. physics

    In 1956, Frank Lloyd Wright proposed the construction of a mile-high building in Chicago. Suppose the building had been constructed. Ignoring Earth's rotation, find the change in your weight if you were to ride an elevator from the street level, where you
  62. Physics

    In 1956, Frank Lloyd Wright proposed the construction of a mile-high building in Chicago. Suppose the building had been constructed. Ignoring Earth's rotation, find the change in your weight if you were to ride an elevator from the street level, where you
  63. physics

    In 1956, Frank Lloyd Wright proposed the construction of a mile-high building in Chicago. Suppose the building had been constructed. Ignoring Earth's rotation, find the change in your weight if you were to ride an elevator from the street level, where you
  64. physics

    In 1956, Frank Lloyd Wright proposed the construction of a mile-high building in Chicago. Suppose the building had been constructed. Ignoring Earth's rotation, find the change in your weight if you were to ride an elevator from the street level, where you
  65. science

    An astronaut who weighed 170 pounds on Earth found that his weight on Jupiter was 400 pounds. He captured an alien that weighed 120 pounds on Jupiter. What is the alien's weight on Earth? A. 34 pounds B. 51 pounds C. 78 pounds D. 283 pounds
  66. Calc./ Physics

    when apollo 15 astronaut David Scott dropped a hammer and a feather on the moon to demostrate that in a vacuum all bodies fall with the same (constant) acceleration, he droppes them from 4 feet above the lunar surface. the television shows them fallen more
  67. science

    What is F1= 125N North
  68. SS ICY NORTH

    HELP I NEED A TO READ ON ICY NORTH WHAT DO I READ
  69. Pre calculus, vectors

    A straight river flows at a speed of 20km/h. A boater starts at the south shore and heads in ths direction of 70degrees from the shore. The boat has a speed of 20km/h in still water. Find the true speed and direction of the boat.
  70. Math (pre calc)

    You have recently been promoted and are now a senior pilot with BHS Exprress, providing courteous and timely service to countless cities across the Northeast. In order to arrive in New York City at the scheduled time, you know you must fly at a speed of
  71. U.S History - Pls check my answer :)

    Document A: It is impossible that the allied powers should extend their political system to any portion of either continent without endangering our peace and happiness; nor can anyone believe that our southern brethren, if left to themselves, would adopt
  72. Chem

    Hello What is the wavelength (in nm) of the line in the spectrum of the hydrogen atom that arises from the transition of the electron from the orbital with n =5 to the orbital with n = 2? Note, the line corresponds to the energy of the photon that is
  73. Algebra Word Problem

    I REALLY NEED YOUR HELP !!!!!!! Suppose it takes 3 days for a space vehicle to travel from Earth to the moon. About how long would it take the same vehichle traveling at the same speed to reach Venus? Closest Distance From Earth to: Moon 240,000mi Venus
  74. physics

    A cyclist starts from point X and rides 3 km due west to point Y. At Y he changes direction and rides 5km north-west to point Z. (a) hw far is he from the starting point, correct to the nearest km? Find the bearing of the Z frm X to the nearest degree?
  75. trig

    two trains leave Kansas City at the same time. Train A is traveling due north at 55 mph, train B is traveling west at the rate of 65 mph. Find the distance between the two trains two hours later and the bearing of train B from train A.
  76. physics

    An aircraft is flying at the speed of 354km/hr relative to the air is observed from the ground to have a velocity of 300km/hr in the north east direction. The wind is blowing from east. Find the speed of the wind and the direction to which the aircraft is
  77. Physics

    Calculate the effective value of g, the acceleration of gravity, at 6400m , above the Earth's surface. Calculate the effective value of g , the acceleration of gravity, at 6200km , above the Earth's surface
  78. metreology

    Wien’s radiation law says that the wavelength of most intense radiation (λmax) emitted by a blackbody is inversely proportional to the absolute temperature (T) of the object. The surface of the Sun radiates as a blackbodyat a temperature ofT=6000
  79. physics

    The gravitational force that the sun exerts on the moon is perpendicular to the force that the earth exerts on the moon. The masses are: mass of sun=1.99 × 1030 kg, mass of earth=5.98 × 1024 kg, mass of moon=7.35 × 1022 kg. The distances shown in the
  80. physics

    The gravitational force that the sun exerts on the moon is perpendicular to the force that the earth exerts on the moon. The masses are: mass of sun=1.99 × 1030 kg, mass of earth=5.98 × 1024 kg, mass of moon=7.35 × 1022 kg. The distances shown in the
  81. physics

    A satellite is in a circular earth orbit that has a radius of 6.63E+6 m. A model airplane is flying on a 16.4 m guideline in a horizontal circle. The guideline is nearly parallel to the ground. Find the speed of the plane such that the plane and the
  82. Environmental Problems

    Where in the US and Canada is deforestation, air pollution, water pollution, and climate change happening? San Francisco Aereas near all population centers would be the most acute, as you get further North the polution is less and, the deforestation is
  83. ap physics

    A star the size of our Sun runs out of nuclear fuel and, without losing mass, collapses to a white dwarf star the size of our Earth. The radius of our Sun is 6.96×108m , the radius of Earth is 6.37×106m . If the star initially rotates at the same rate as
  84. ALGEBRA

    1. Many people know that the weight of an object varies on different planets, but did you know that the weight of an object on Earth also varies according to the elevation of the object? In particular, the weight of an object follows this equation: , where
  85. Physics

    A star the size of our Sun runs out of nuclear fuel and, without losing mass, collapses to a white dwarf star the size of our Earth. The radius of our Sun is 6.96×108m , the radius of Earth is 6.37×106m . If the star initially rotates at the same rate as
  86. physics

    A star the size of our Sun runs out of nuclear fuel and, without losing mass, collapses to a white dwarf star the size of our Earth. The radius of our Sun is 6.96×108m , the radius of Earth is 6.37×106m If the star initially rotates at the same rate as
  87. Physics

    The average intensity of sunlight at earth's surface is approximately 1400 W/m^2 , if the Sun is directly overhead. The average distance between the earth and the sun is 1.50E11 m. What is the average power emitted by the Sun? Ok so intensity is power over
  88. Chem -plz check work

    so i've worked on this some more, now I am asking if someone will plz check my work 2 half cells in a galvanic cell consist of one iron Fe(s) electorde in a solution of iron (II) sulphate FeSO4(aq)and a silver Ag(s) electrode in a silver nitrate solution,
  89. Physics

    In a computer monitor, an electron beam with a current of 4x10^-6 A is directed at the screen. How many electrons are transferred to the monitor in 2 minutes.
  90. Physics check

    If an atom has 104 electrons, 157 neutrons, and 104 protons, what is the atomic number of the nucleus? have no idea
  91. Physics E&M

    Three electrons form an equilateral triangle 1.00 nm on each side. A proton is at the center of the triangle.What is the potential energy of this group of charges?
  92. chemistry

    what is the binding energy of an electron in a photosensitive metal (in kj/mol) if the minimum frequency of light that can eject electrons from the metal is 6.3 x 20^14 Hz?
  93. Int. science

    Which of the following is an example of a cycle theme in science? seasons electrons and protons the solar system relationship between plants and animals
  94. Chemistry (Electrons in Atoms)

    What is the wavelength of the emitted photon, when the electron in the hydrogen atom makes a transition from the ni = 5 state to the nf = 3 state?
  95. science

    i have a work sheet to do it gives me the atomic number and the mass number of elements i have to fill in the missing electrons protons neutrons
  96. Chemistry

    A metal foil has a threshold frequency of 5.45× 1014 Hz. Which of the colors of visible light have enough energy to eject electrons from this metal.
  97. physics

    two identical copper spheres are separated by 1m in vacuum. how many electrons would have to be removed from one sphere and added to other sphere so that they attract each other with force of 0.9N
  98. Electronic Instrumentation

    Calculate the force in Newtons that exists between a positive charge of 2C and a negative charge of 5.2 X 10^19 electrons separated by a distance of 25 cm.
  99. physics

    Problem 22.2 2 *10^13 electrons flow through a transistor in 1.0ms . Part A - What is the current through the transistor? Express your answer using two significant figures. in mA
  100. Physics

    When two identical ions are separated by a distance of 5.9 multiplied by 10-10 m, the electrostatic force each exerts on the other is 6.0 multiplied by 10-9 N. How many electrons are missing from each ion?