Questions Asked in February 2007

Most Popular Questions of February 2007

  1. CHEMISTRY

    HOW CAN U TELL IF HNO3 +KNO3 IS A BUFFER SOLUTION A buffer solution must contain a weak acid and its conjugate base OR a weak base and its conjugate acid. HNO3 is a strong base and KNO3 is the salt of a strong base (KOH) and a strong acid (HNO3);

    asked by CANDY on February 27, 2007
  2. Statistics

    A sign on the gas pump of a certain chain of gasoline stations encourages customers to have their oil checked, claiming that one out of every four cars should have its oil topped up. What is the probability that exactly 3 of the next 10 cars entering a

    asked by Matt on February 10, 2007
  3. physics

    If a gasoline engine has an efficiency of 21 percent and loses 780 J to the cooling system and exhaust during each cycle, how much work is done by the engine? Is it 3709.5??? Chemical energy in (as fuel and oxygen) = Work out + Heat out 21% is the ratio of

    asked by anonymous on February 15, 2007
  4. Chemisry

    what mass of protons would be required to just neutralize the charge of 1.0g of electrons? how do I answer this? You know the mass of an electron. Calculate how many are in 1 gram. You will need the same number of protons. Knowing the mass of a proton

    asked by Chris on February 8, 2007
  5. physics

    Please see if I am doing this problem right. A mixture of gasoline vapor and air is placed in an engine cylinder. The piston has an area of 7.4 X 10^-3 m^2 and is displaced inward by 7.2 X 10^-2 M. If 9.5 X 10^5 Pa of pressure is placed on the piston, how

    asked by Anonymous on February 4, 2007
  6. chem

    For the reaction 3NO2 + H2O  2HNO3 + NO, how many grams of HNO3 can form when 1.00 g of NO2 and 2.25 g of H2O are allowed to react? This is a limiting reagent problem. 1. Write the equation. You have done that and it is balanced. 2. Convert 1.00 g NO2 and

    asked by meghan on February 28, 2007
  7. Physics

    Location A is 3.00 m to the right of a point charge q. Location B lies on the same line and is 4.70 m to the right of the charge. The potential difference between the two locations is VB - VA = 45.0 V. What is the magnitude and sign of the charge?

    asked by Anna on February 5, 2007
  8. Chemistry (please help me!)

    H2(g) + CO2(g) H20(g) + CO(g) When H2(g) is mixed with CO2(g) at 2,000K, equilibrium is achieved according to the equation above. In one experiment, the following equilibrium concentrations were measured: [H2]=0.20 M [CO2]=0.30 M [H2O]=[CO]=0.55M a) What

    asked by sara on February 25, 2007
  9. Exponents-word problem

    A culture starts at 8600 bacteria. After one hour the count is 10,000. Find a function that models the number of bacteria n(t) after t hours. The answer is n(t) = 8600e^.1506t Where does this 0.1506 come from? Thanks. n(t) = 8600 e^(kt), where k is an

    asked by Jen on February 16, 2007
  10. Math Homework

    1) Given the side of a square pyramid is 6cm and the altitude is 4cm calculate the surface area. 2) Given the side of a square pyramid is 12cm and the altitude is 8cm calculate the surface area. 3) Given the side of a square pyramid is 18cm and the

    asked by Student on February 6, 2007
  11. Grammar

    When learning pronoun case (subjective pronoun,objective,possessive) do I need to just memorize the list? I am having trouble identifying them. Any help please. I am in 5th grade. I recommend memorize, using homemade flash cards. It wont take long to

    asked by Lex on February 14, 2007
  12. history- world war 1 entrance

    What slowed down the U.S. entrance into World War 1? I already have many Americans simply did not want to send their sons to war and pacifists urged the United States to set an example for peace. I need one more. Your question presumes it should have been

    asked by Anonymous on February 1, 2007
  13. s.s

    before there was mills what was used to make thread? Before there were mills and factories, people made thread at home on spinning wheels. Check this site for more information and a picture of a spinning wheel. http://en.wikipedia.org/wiki/Spinning_wheel

    asked by Melsissa on February 8, 2007
  14. chem

    which of the following is a chemical reaction? A) propane forms a flame and emits heat as it burns. B) Acetone feels cold as it evaporates from the skin. C) Bubbling is observed when potassium carbonate and hydrochloric acid solutions are mixed. D) Heat is

    asked by Jenn on February 20, 2007
  15. SCIENCE

    What type of bonding holds the compound, sodium cyanide, together? The CN bond is covalent. The Na to CN bond is, in most minds, an ionic bond. The electronegativity of C is about 2.1 and that of Na is about 1; therefore, with a difference of about 1 it is

    asked by MARK on February 7, 2007
  16. Science-Enr. Phys.

    A box of books weighing 325 N moves at a constant velocity across the floor when the box is pushed with a force of 425 N exerted downward at an angle of 35.2 degrees below the horizontal. Fink Mu,k between the box and the floor. There have been several of

    asked by Sara on February 25, 2007
  17. physics- please check

    a. Two sticks are rubbed together to start a fire. b. A firecracker explodes. c. A red-hot iron bar is set aside to cool. In which of the situations listed above is energy being transferred as heat to the system in order for the system to do work? I would

    asked by Anonymous on February 4, 2007
  18. Biology

    The endosymbiont hypothesis offers an explanation for how eukaryptoc cells could have obtained mitochondria and chloroplasts through a symbiotic relationship with prokaryotic cells that changed over time. What structural feature of prokaryotic cells might

    asked by Marisol on February 14, 2007
  19. Physics

    A person is making homemade ice cream. She exerts a force of magnitude 17 N on the free end of the crank handle, and this end moves in a circular path of radius 0.28 m. The force is always applied parallel to the motion of the handle. If the handle is

    asked by Mary on February 23, 2007
  20. Chemistry

    This problem of the limiting reactant is: Given the reactant amounts specified in each chemical reaction, dtermine the limiting reactant in each case: (I'm just going to take one problem out of the bunch} HCl + NaOH yeilds NaCl + H2O 2.00 2.50 mol mol

    asked by Beautiful on February 24, 2007
  21. PHYSICS - still cant get it

    A 0.30-kg softball has a velocity of 12 m/s at an angle of 30° below the horizontal just before making contact with the bat. What is the magnitude of the change in momentum of the ball while it is in contact with the bat if the ball leaves the bat with a

    asked by winterWX on February 24, 2007
  22. physics

    A wooden artifact is found in an ancient tomb. Its carbon-14 activity is measured to be 60.0% of that in a fresh sample of wood from the same region. Assuming the same amount of carbon-14 was initially present in the wood from which the artifact was made,

    asked by soojung on February 16, 2007
  23. biology

    Are an organism's characteristics determined only by its genes? Explain. Yes, an organism's characteristics are determined only by It's genes becuase the parents give their offspring genes which determines their characteristics. Is my answer correct? Do I

    asked by franny on February 25, 2007
  24. Music

    How do i put graphic notation into a composition table ???????????? Thank you for using the Jiskha Homework Help Forum. Here is a site that even shows an example: http://www.upto11.net/generic_wiki.php?q=musical_notation

    asked by Angelica on February 26, 2007
  25. math

    Derivatives are usually not taught in 5th grade. That is what your question is about: Rates of change. Complete the following statements with the correct words Note: Correct spelling is important. If s(t) is a distance (or height or position) function,

    asked by drwls on February 19, 2007
  26. Physics (Newton's laws)

    Two blocks of mass 3.50 kg and 8.00 kg are connected by a massless string that passes over a frictionless pulley. The inclines are frictionless and the angles with the horizontal is 35 degrees. Find a) the magnitute of the acceleration of each block and b)

    asked by Eric (please help me) on February 15, 2007
  27. Economics

    Why do people routinely stuff themselves at all-you-can-eat buffets? Explain in terms of both utility and demand theories. At any level, the marginal cost of take another bite at an all-you-can-eat place is zero. In terms of utility, a person should

    asked by Kayla on February 4, 2007
  28. Chemistry - Rate Determining Step

    The rate law for the reaction 2NO (g) + Cl2 (g) -> 2NOCl (g) is given by rate = k[NO][Cl2] A mechanism involving the following steps has been proposed for the reaction: NO (g) + Cl2 (g) -> NOCl2 (g) NOCl2 (g) + NO (g) -> 2NOCl (g) If this mechanism is

    asked by Christine on February 6, 2007
  29. physics

    A ferry boat is 4.0 m wide and 6.0 m long. When a truck pulls onto it, the boat sinks 4.00 cm in the water. What is the combined weight of the truck and the ferry?

    asked by bobert on February 20, 2007
  30. Calculus

    The power P (in W) generated by a particular windmill is given by P = .015 V^3 where V is the velocity of the wind (in mph). Find the instantaneous rate of change of power with respect to velocity when the velocity is 5.7 mph. P = 0.015 V^3 dP/dV = 0.045

    asked by Anonymous on February 13, 2007
  31. Chem.

    If 0.130 g of p-aminophenol is allowed to react with excess acetic anhydride , what is the theoretical yield of acetaminophen in moles? In grams? p-amino. - MW: 109.13g aceta. - MW: 151.16 g ** I just forgot how to do this, I know it's probably REALLY

    asked by Richard on February 27, 2007
  32. polynomials & rational function

    A drug is administered to a patient and the concentration of the drug in the bloodstream is monitored. At time t >= 0(in hours since giving the drug) the concentration is given by(in mg/L) c(t) = 5t / (t^2+1) Graph the function. From the graph, how do I

    asked by Jen on February 2, 2007
  33. chem

    An automobile burns 65 grams of gasoline over 20 minutes. The gasoline combines with 100 grams of oxygen in this reaction, to form carbon dioxide and 47 grams of water. How much carbon dioxide is formed? do I use the heat capacity equation? How much oxyen

    asked by tina on February 14, 2007
  34. More Chemistry

    I have the answers, I just want to be sure...I'm a little hesitant.. 1. Explain how strong acid solutions conduct an electric current: -Strong acids readily release ions creating electro negativity. 2. Will a strong acid or weak acid conduct electricity

    asked by Liz on February 15, 2007
  35. Physics

    A 4 kg mass is sliding on a fricitonless surface and explodes into two, 2 kg parts. One moving at 3 m/s due north and the other at 5 m/s 30 degrees north of east. What is the original speed of the mass? Can you please verify if my answer is correct? I used

    asked by sarah on February 9, 2007
  36. physics- isothermal, isovolumetric, or adiabatic

    Please check my answers. Identify the following processes as isothermal, isovolumetric, or adiabatic: a. a tire being rapidly inflated- adiabatic b. a tire expanding gradually while heating- isothermal c. a tire being heated while in a rigid metal

    asked by Anonymous on February 4, 2007
  37. ALGEBRA 1

    If x and 3x-10 represent the measure of the acute angles of a right tringle find the value of x. THANKS Let's take it step by step. A triangle has 3 angles in it. Those three angles, when added together, is 180. In a right triangle, one of the angles is 90

    asked by DANIELLE on February 12, 2007
  38. econ

    Suppose the production function for widgets is given by: Q = KL - 0.8K^2 - 0.2L^2 where Q represents the quantity of widgets produced, K represents the annual capital input and L represents annual labor input. (a) For K = 10, what is the average

    asked by Vincy on February 18, 2007
  39. physics

    A 35-kg skier skis directly down a frictionless slope angled at 11° to the horizontal. Assume the skier moves in the negative direction of an x axis along the slope. A wind force with component Fx acts on the skier. What is Fx (in N) if the magnitude of

    asked by **chocolatekisses on February 8, 2007
  40. maths, proportion

    twelve men take 6 hours to finish a piece of work. after the 12 men have worked for 1 hour, the contractor decides to call in 8 more men to complete the remaining work. how many more hours would the 20 men take to complete the remaining piece of work? is

    asked by minerva on February 24, 2007
  41. physics......PLEASE HELP!!

    A steam engine absorbs 1.98*10^5 J and expels 1.49*10^5 J in each cycle. Assume that all of the remaining energy is used to do work. a. What is the engine's efficiency? b. How much work is done in each cycle? If a gasoline engine has an efficiency of 21

    asked by anonymous on February 14, 2007
  42. chemistry

    what is the molecular geometry and bond angles of CF2Cl2? Is there any reason to suspect this won't be tetrahedral with bond angles of 109.5? The difference in electronegativity between F and Cl would be expected to alter the angles somewhat.

    asked by karla on February 26, 2007
  43. chemistry

    If heat of reaction, Ca(s) + 2H+(aq) Ca2+(aq) + H2(g) , is - 544 kJ/mol, heat of reaction, CaO(s) + 2H+(aq) Ca2+(aq) + H2O(l) , is -192 kJ/mol. and heat of formation of water is -286, what is heat of CaO? i found that the formation of CaO is -638. However,

    asked by nicholas on February 11, 2007
  44. More Organic Chem.

    1. Would you expect ibuprofen to be soluble or insoluble in 1.0 M NaOH? Explain. 2. Thymol is very slightly soluble in water and very soluble in 1.0 M NaOH. Explain. Any info. would help! Below are two web pages. The first shows ibuprofen has a -COOH group

    asked by Richard on February 5, 2007
  45. Physics help----------thanks

    A charged cloud system produces an electric field in the air near the Earth's surface. A particle of charge -2.2 10-9 C is acted on by a downward electrostatic force of 3.0 10-6 N when placed in this field. (c) What is the magnitude of the gravitational

    asked by Frank on February 15, 2007
  46. Chemistry Periodic Trends

    The electron affinities of the elements from aluminum to chlorine are -44, -120, -74, -200.4, and -384.7 kJ/mol respectively. Rationalize the trend in these values. Electron affinity is the energy absorbed (endothermic) or emitted (exothermic) by the

    asked by Will on February 11, 2007
  47. Physics

    You are given two unknown point charges, Q1 and Q2. At a point on the line joining them, one-third of the way from Q 1 to Q2, the electric field is zero. Are Q1 and Q2 like or unlike charges? How many times greater is Q2 than on Q1? I am really confused on

    asked by Nat on February 22, 2007
  48. Math

    1) Which of the following ingegers can not represent the lengths of the sides of a triangle? (9,10,11) (4.7,9) (4,8,12) & (6,6,11) Try drawing the 4,8,12 triangle. Have fun. any two sides must be longer than the third. Example with set 1. 9+10>11 10+11>9

    asked by Peggy on February 23, 2007
  49. Chemistry

    write isotpoic symbols of the form X-A (for example, C-13) for each of the following isotopes. **Do I add the number of protons and neutrons together to get the answer? The symbol is easy to figure out.** a) the iodine isotope with 74 neutrons B) the

    asked by Melinda on February 8, 2007
  50. winterWx

    What is the average translational kinetic energy of nitrogen molecules at 1500 K, in the following units? (a) J (b) eV I already provided the formula for average KE in Joules, in an answer to a separate question of yours. average KE = (3/2) k T 1 eV =

    asked by Physics/Math on February 23, 2007
  51. Lab conclusion- HELP!

    I' am currently trying to wrie a couple of lab conclusions and having a hard time coming up with good points to make for the following lab experiment: Thin layer chorotography If anyone has a few minutes to give me a couple tips on how to improve this. I

    asked by Richard on February 5, 2007
  52. Calculus

    The average temperature T(x), in oF, in a small office building without air conditioning given by T(x) = 73 ¨C 14 cos (p (x ¨C 3.4))/12 where x is the time elapsed since midnight, 0 ¡Ü x ¡Ü 24. To cool the building, the air conditioning is turned on

    asked by C.Lopez on February 26, 2007
  53. AP Chemistry

    (a) What is the pH of a 2.0 molar solution of acetic acid. Ka of acetic acid = 1.8 x 10¯5 (b) A buffer solution is prepared by adding 0.10 liter of 2.0 molar acetic acid solution to 0.1 liter of a 1.0 molar sodium hydroxide solution. Compute the hydrogen

    asked by Dave on February 13, 2007
  54. physics.......please help!!!

    In which of the situations listed below is energy being transferred as heat to the system in order for the system to do work? In which situation is work being done on the system in order for energy to be transferred from the system as heat? a. Two sticks

    asked by anonymous on February 9, 2007
  55. physics (elastic collision)

    A ball of mass .44 kg and speed of 4.5 m/s collides head-on with a .22 kg ball at rest. Assuming perfect elasticity, what is the speed and direction of each ball afterwards? I know that the momentum is conserved here and since I am solving fo two

    asked by sean on February 1, 2007
  56. Physics/Math

    At time t1 = 2.00 s, the acceleration of a particle in counterclockwise circular motion is (9.00i + 8.00j) m/s^2. It moves at constant speed. At time t2 = 3.00s (3/4 of a revolution later), it's acceleration is (8.00i - 9.00j) m/s^2. Find the radius of the

    asked by COFFEE on February 18, 2007
  57. Chem

    A mixture of chromium and zinc weighing .362 g was reacted with an excess of hydrochloric acid. After all the metals in the mixture reacted 225 mL of dry hydrogen gas was collected at 27 C and 750 torr. Determine the mass percent Zn in the metal sample.

    asked by Jim on February 25, 2007
  58. Math

    the distance between any two bases on a baseball diamond is 90 feet.What is the best approximation for the direct distance from home plate to second base? A baseball diamond's four bases form a square with 90 foot sides. A right triangle is formed by home

    asked by Alexandria on February 14, 2007
  59. Math/Physics

    The velocity v of a particle moving in the xy plane is given by v = (6.0t - 4.0t2) i + 4.0 j, with v in meters per second and t (> 0) is in seconds. What is the acceleration when t = 3.0 seconds? When is the acceleration zero? When is the velocity zero?

    asked by winterWX on February 1, 2007
  60. chemistry

    1. A three-step mechanism has been suggested for the formation of carbonyl chloride: Step 1: Cl2 ===> 2 Cl (fast equlibrium) Step 2: Cl + CO ===> COCl (fast equilibrium) Step 3: COCl + Cl2 ===> COCl2 + Cl (slow) What is the molecularity of the

    asked by Issac on February 9, 2007
  61. Poetry question

    Poems that use onomatopoeia arouse the sense of: sound, touch, smell or sight? Doesn't poems that use onomatopoeia ariuse the sense of sound? I think that it is sound. It is a word that is used to create a sound effect. for example sizzle, snap sorry- I

    asked by Bailey on February 6, 2007
  62. Math (Calculus 121)

    Consider the following function. f(x) = 7x3 + x2 - 0.08x + 12 Find the two points on the graph at which the tangent line is horizontal. Give your values correct to 2 decimal places. ( , ) (point with smaller x value) ( , ) (point with larger x value)

    asked by Lia on February 19, 2007
  63. biology

    With each cell division , the chromosomes are divided between 2 daughter cells, yet the number of chromosomes in each cell does not change. What process ensures that the normal number of chromosomes is restored after each cell division? During which part

    asked by marco on February 5, 2007
  64. Chemistry

    An important process for the production of acrylonitrile C3H3N is given by the following reaction 2C3H6 + 2NH3 + 3O2 --> 2C3H3N + 6H2O A 150 -L reactor is charged tot he following partial pressures at 25 C P(C3H6) = .5 MPa P(NH2) = .8 MPa P(O2) = 1.5 MPa

    asked by Kim on February 25, 2007
  65. word problem

    The half life of cesium-137 is 30 years. Suppose we have a 10-g sample. a)Find a function that models the mass remaining after t years. b)How much of the sample will remain after 80 years? c)After how long will only 2 g of the sample remain? Thanks (a)

    asked by Jen on February 14, 2007
  66. Science

    COMPOUND 1 CH2=CH-CH-OH ________| _______CH3 COMPOUND 2 _____________O ____________// CH3-CH-CH2-C _____|______\ ____CH3______OH *Now, I must: Identify any functional groups in these compounds and name them. The functional group in 1 is the OH which makes

    asked by Shane on February 7, 2007
  67. Physics

    A 6090kg space probe mobing nose-first toward Jupiter at 105m/s relative to the Sun, fires its rocket engine ejecting 80 kg of exhaust at a speed of 253 m/s relative to the space probe. What is the final velocity of the probe? I should have gotten 108m/s

    asked by Tammy on February 2, 2007
  68. physics

    an 800 N person stands on a scale in an elevator. What is his apparent weight when the elevator is accelerating upward at 2 m/s^2? B) what5 is his apparent weight when the elevator is acc. downward at 2m/s^2? c) what is his apparent weight when the

    asked by Sabrina on February 20, 2007
  69. IDIOM

    GRABBING THE BULL BY THE HORNS A WOLF IN SHEEP'S CLOTHING Thank you for using the Jiskha Homework Help Forum. This expression means to "get right to the point." If you have something to say you do not "beat around the bush" but come right out and say it.

    asked by ray on February 21, 2007
  70. Elements

    Which elements result if two protons and two neutrons are ejected from a radium nucleus with atomic number 88 and mass number 226? What element is atomic number 86 and mass 222? Sorry, should be atomic number 88. Huh? It ejected two protons, changing the

    asked by Sam on February 4, 2007
  71. Chem

    Butane, C4H10, is widely used as a fuel for disposable lighters. When one mole of butane is burned in oxygen, carbon dioxide and steam are formed and 2658 kJ of heat is evolved. a) Write the thermochemical equation for the reaction. First I wrote the

    asked by Chris on February 1, 2007
  72. PHYSICS helppppp

    A 0.2 kilogram baseball is thrown vertically downwards towards to the same horizontal floor. The baseball possesses an initial velocity of 30 meters per second. The height is 10.00m. (A) Calculate the POTENTIAL GRAVITATIONAL ENERGY and KINETIC ENERGY of

    asked by Katrina on February 19, 2007
  73. physics

    a) In raising a 4800 N piano with a pulley system, the workers note that for every 2 m of rope pulled down, the piano rises 0.3 m. Ideally, how much force is required to lift the piano? (b) If the workers actually pull with 2500 N of force to lift the

    asked by janice on February 8, 2007
  74. organic chemistry

    1)Why benzoic acid is soluble in NaOH? 2)Why HCl is insoluble in titration of benzoic acid and NaOH? Benzoic is soluble in a solution of NaOH because the base forms the sodium salt with the acid to form sodium benzoate. The sodium salt is soluble. The

    asked by kim on February 21, 2007
  75. Physics HELP!!!!!!!!

    For the normal force in Figure 5.21 to have the same magnitude at all points on the vertical track, the stunt driver must adjust the speed to be different at different points. Suppose, for example, that the track has a radius of 3.1 m and that the driver

    asked by Mary on February 21, 2007
  76. algebra

    Can someone please help me do this problem? That would be great! Simplify the expression: sin theta + cos theta * cot theta I'll use A for theta. Cot A = sin A / cos A Therefore: sin A + (cos A * sin A / cos A) = sin A + sin A = 2 sin A I hope this will

    asked by Valerie on February 18, 2007
  77. Standing waves and resonance (physics)

    A nylon string has a linear density of 7.2g/m and is under a tension of 150N. The fixed supports are 90cm apart. The string is oscillating in the standing wave pattern. Find a)speed b)wavelength c) frequency v=sqr(F/u(linear density) v=sqrt(150N/7.2g/m) =

    asked by Susane on February 6, 2007
  78. English

    Act 1 Scene 1 .. Romeo & Juliet I don't know the answer to two of my questions for Romeo and Juliet the first one . . . Although Rome and Juliet is a tragedy, much of the play is quite comic. Outline briefly the comic elements in this scene. To whatextent

    asked by Becca on February 13, 2007
  79. Science

    List ways simple plants affect your life each day. (HINT: Where do electricity and heat for homes come from?) food, heat and electricity(from fossils and coal and oil), cars (gasoline from oil), etc.

    asked by Jessica on February 7, 2007
  80. english - idea on how to conclude a paragraph?

    My introductory sentence is this: My least favourite musical performer is none other than the princess of pop herself, Britney Spears, otherwise affectionately known as Brit Brit in some blogging communities. I talk about some of her 'wild antics' in the

    asked by anna on February 19, 2007
  81. Physics

    A force of 8.4 N is exerted on a -8.8µC charge in a downward direction. What is the magnitude and direction of the field? How would I set up this problem? Force= Eq solve for E.

    asked by Nat on February 22, 2007
  82. PHYSICS!!!

    A 0.30-kg softball has a velocity of 12 m/s at an angle of 30° below the horizontal just before making contact with the bat. What is the magnitude of the change in momentum of the ball while it is in contact with the bat if the ball leaves the bat with a

    asked by winterWX on February 24, 2007
  83. RE: PHYSICS

    A man (weighing 915 N) stands on a long railroad flatcar (weighing 2805 N) as it rolls at 18.0 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at 40.00 m/s relative to

    asked by COFFEE on February 26, 2007
  84. Physics

    An archer shoots and arrow horizontally at a target 15m away. The arrow is aimed directly at the center of the target, but it hits 52 cm lower. What was the initial speed of the arrow? I know it has something to do with a zero launch angle but none of the

    asked by Mike on February 1, 2007
  85. chemistry

    how many molecules are present in 4.25 mol if CCl4? 1 mol = 6.022 x 10^23 molecules Therefore, how many molecules are in 4 moles? I don't have a calculator to figure out that problem, but I do understand it. i mn

    asked by larry on February 7, 2007
  86. Electronic Field

    At some instant the velocity components of an electron moving between two charged parallel plates are vx = 1.3 105 m/s and vy = 3.6 103 m/s. Suppose that the electric field between the plates is given by E = (120 N/C) j. (a) What is the electron's

    asked by Jennifer on February 15, 2007
  87. Maths- complex numbers

    Find tan(3 theta) in terms of tan theta Use the formula tan (a + b) = (tan a + tan b)/[1 - tan a tan b) in two steps. First, let a = b = theta and get a formula for tan (2 theta). tan (2 theta) = 2 tan theta/[(1 - tan theta)^2] Then write down the equation

    asked by Jake on February 13, 2007
  88. Chemistry

    What is the net ionic equation when H2SO4 is neutralized by NaOH in aqueous solution? Write the molecular equation. H2SO4 + 2NaOH ==> Na2SO4 + 2H2O Convert to ions. 2H^+ + SO4^= + 2Na^+ + 2 OH^- ==> 2Na^+ + SO4^= + 2H2O Now cancel those ions that appear on

    asked by Bob on February 17, 2007
  89. Chemistry (Check)

    Part B True-False Classify each of the statements as always true, sometimes true, or never true. 1.____ST______ one mole of any gas occupies a volume of 22.4 L. 2_____NT______ for a substance of known molar mass, the number of moles of a sample can be

    asked by Bryan on February 5, 2007
  90. Physics

    A vessel at rest explodes breaking into three pieces. Two pieces, having equal mass fly off perpendicular to one another with the same speed of 30 m/s. The third piece had three times the mass of each other piece. What are the magnitude and direction of

    asked by sarah on February 10, 2007
  91. math

    what is monomial a monomial is one term containing variables or constants. see merriam webster website too. look up monomial. hope it helps!

    asked by jose on February 12, 2007
  92. Physics

    The drawing shows a plane diving towards the ground and then climbing back upward. During each of these motions, the lift force L acts perpendicular to the dispacement s, which has the same magnitude of 2.8 103 m in each case. The engines of the plane

    asked by Mary on February 27, 2007
  93. physics (please help)

    Two identical but separate strings, with the same tension, carry sinusoidal waves with the same frequency. Wave A has an amplitude that is twice that of wave B and transmits energy at a rate that is _____ that of wave B. a)half b)twice c) one-fourth d)four

    asked by susan on February 13, 2007
  94. algebra , help

    Can someone help me set up the equations thanks. Directions: Solve each of the following applications. Give all answers to the nearest thousandth. Problem: Geometry. The length of a rectangle is 1 cm longer than its width. If the diagonal of the rectangle

    asked by jas20 on February 20, 2007
  95. Science/Chem

    How many representative particles are in 2.5 mol H2O2? each mole consists of 6.02*10^23 things. Memorize that.

    asked by Dennis on February 4, 2007
  96. Biology

    What law of thermodynamics explains the fact that if you drop an egg, the shell will not spontaneously repair itself? The second law

    asked by aj on February 24, 2007
  97. Re: PHYSICS

    "Relative" is an important word. Block L of mass mL = 1.90 kg and block R of mass mR = 0.500 kg are held in place with a compressed spring between them. When the blocks are released, the spring sends them sliding across a frictionless floor. (The spring

    asked by COFFEE on February 27, 2007
  98. science

    calculate the amount of heat evolved in the complete oxidation of 8.17g of Al at 25 degrees C and 1 atm pressure. change in H for Al2O3 is -1676kJ/mol. 4Al(s) + 3O2(g)--> 2Al2O3(s) please giv me the steps to solving this thanx. delta H = -1676 kJ/mol How

    asked by michelle on February 6, 2007
  99. reading: personification

    How is personification an effective writting tool? *w*w*w*.*a*s*k*.*c*o*m* hey i cant help but heres a hint just go 2 (go on the words w/ the stares around them )and ask the question Here are some really good sites explaining the use of personification.

    asked by lilly on February 21, 2007
  100. Physics...Friction

    A 75 kg box slides down a 25 degree ramp with an acc. of 3.6 m/s2. find mu,k between the box and the ramp. Write down Newton's second law for the direction of motion. "a" is the acceleration. Mg sin 25 - M g cos 25 *mu,k = M a The first term is the weight

    asked by Christy on February 24, 2007