1. Chemistry 212

    the half life of F18 is 2.089x10^-4yrs. How long would it take (in days) for F18 to decrease to 78.71% of its initial amount?
  2. physics

    Two charges are separated until they are a distance of 191 cm apart, causing the electric force between them to increase by a factor of exactly 5. What was their initial separation distance?
  3. Physics

    An electron has an initial speed of 4.00×106 m/s. What potential difference (sign and magnitude) is required to bring the electron to rest?
  4. physics

    An automobile with an initial speed of 3.25 m/s accelerates uniformly at the rate of 3.2 m/s2. Find the final speed of the car after 4.4 s. Answer in units of m/s
  5. Physics

    A boy throws a stone with an initial velocity of 14.6 m/s and it returns to his hand in 3 seconds. What maximum height does the stone reach?
  6. algebra

    a diver springs from the edge of a cliff 80 ft above the ocean with an initial upward velocity of 8 ft/ s. How long will it take the diver to reach the water?
  7. Science

    A ball thrown from the edge of a 35m high cliff takes 3.5s to reach the ground below. What was the ball's initial velocity?
  8. Physics

    A stone is thrown in the air with an initial velocity of 50 m/s at 37 degrees to the horizontal. Find the total time the ball is in the air.
  9. Chemistry PLEASE HELP!!!!!

    Say, for example, that you had prepared a Buffer C, in which you mixed 8.203 g of sodium acetate, NaC2H3O2, with 100.0 mL of 1.0 M acetic acid. a. What would be the initial pH of Buffer C? HOW???????
  10. physics

    A ball is thrown horizontally from the roof of a building 60 m tall and lands 45 m from the base. What was the ball's initial speed? _______m/s
  11. Chemistry

    Say, for example, that you had prepared a Buffer C, in which you mixed 8.203 g of sodium acetate, NaC2H3O2, with 100.0 mL of 1.0 M acetic acid. a. What would be the initial pH of Buffer C? HOW???????
  12. physics

    Suppose Captain Marvel leaps from the top of a 20 m tall building. If his initial speed is 12 m/s, then what is his speed just before he lands on the ground?
  13. Algebra 2

    You invest an initial $100 in an account that has an annual interest rate of 3%, compounded quarterly. How much money will you have in the account after 20 years?
  14. PHYSICS (PLEASE READ)

    I tried all the formulas i know but i cannot answer it I really need your help in this question.. A projectile was launched 64° above the horizontal, attaining a height of 10 m. What is the projectile's initial speed?
  15. chemistry

    What is the final concentration (in M) of 17.6 mL sodium chloride solution with an initial concentration of 1.86 M which is diluted with 18.9 mL of solvent? Assume the volumes are additive.
  16. chem

    A lead fishing weight with a mass of 57 g absorbs 146 cal of heat.If its initial temperature is 48^C, what is its final temperature?
  17. Physics

    A dropping ball initial at rest is dropped 1.5m; calculate a) the traveling time of the ball and b) its velocity just before reaching the ground.
  18. physics

    Kevin tosses a 0.10 kg ball horizontally with an initial velocity of 22.00 m/s. What is in m/s2 the vertical component of the acceleration of the ball 3.82 seconds after he threw it?
  19. Physics

    A ball is thrown horizontally from the roof of a building 45cm tall and lands 24.0m from the base. What was the ball's initial velocity?
  20. Physic

    What is the maximum height above ground a projectile of mass 0.67 kg, launched from ground level, can achieve if you are able to give it an initial speed of 78.5 m/s?
  21. physics

    A particle of mass 1kg moving with initial velocity (i+2k)m/s is acted upon by a constant force(i+2j-2k)N,calculate the velocity and distance after 5s.
  22. physics

    A fully charged 98 uF capacitor is discharged through a 125 ohms resistor. How long will it take for the capacitor to lose 75% of its initial energy
  23. Physics

    At a track and field meet, the best long jump is measured as 8.30 m. The jumper took off at an angle of 31 ° to the horizontal. What was the jumper’s initial speed?
  24. physics

    when Chris slams a basketball he has a vertical leap of 1.46 meters. what must his initial vertical velocity be in order for him to reach this height?
  25. physics

    A ball is thrown vertically upward from the edge of a cliff of height 131 m. The initial velocity is 77.7 m/s. how high is the cliff?
  26. PHYICS NEED HELP BAD!

    A football is kicked 66.6 meters. If it is in the air for 5.39 seconds, with what initial velocity was it kicked? magnitude and direction above horizontal
  27. Chemistry

    An ideal gas with an initial volume of 2.30L is cooled to 12.00 Celsius where its final volume is 1.85L. What was the temperature initially?
  28. physics

    boy throws a penny into an empty well with an initial velocity of –2 m/s. He hears it hit the bottom 8 seconds later. About how far did the penny fall?
  29. Physics

    What is the maximum height above ground a projectile of mass 0.67 kg, launched from ground level, can achieve if you are able to give it an initial speed of 78.5 m/s?
  30. physics

    A projectile is launched at an angle of 58.5 degrees above the horizontal and lands at the same level from which it was launched 3.88 seconds later. what is the magnitude of the initial velocity?
  31. physics

    A body of mass 4 kg is dropped from a height of 20m .calculate the initial momentum and the momentum just before it strikes the ground (g=10m/s*s)
  32. Chemistry

    Combustion of natural gas (primarily methane) occurs in most household heaters. The heat given off in this reaction is used to raise the temperature of the air in the house. Assuming that all the energy given off in the reaction goes to heating up only the
  33. Thermodynamics

    The initial state consists of a closed system containing one mole of super-heated liquid water at 115°C and 1 atmosphere pressure. The immediate surroundings are also at 115°C and 1 atmosphere pressure. The change in state is described as this one mole
  34. physits

    if the treadmills initial speed is 1.6 m/s what's it final speed
  35. chem

    I have to balance an equation and I had to make the equation from an experiment we did. So far, my equation looks like this and I know what I have is correct: Cu(NO3)2+H20+NaOH----->Cu(OH)2 I think I probably need an N or a Na on the right side. What do
  36. Chem.....

    Methanol, CH3OH, is produced on an industrial scale from carbon monoxide and hydrogen. At the temperatures used, gaseous methanol is formed according to the following thermochemical equation: CO(g)+ 2H2(g) <---> CH3OH(g) H = -90Kj 1. State Le
  37. Economics

    The market demand and supply curves for an agricultural product are as follows: Qd = 4,500 - 250P; Qs = 200P where quantities are in thousands of bushels per annum and price is in dollars per bushel. The government wishes to achieve a higher point on the
  38. Chemistry

    Help with lab report Need Help finishing my lab report.KNOWN VALUES ARE V OF HCL=50ML,M=2.188.V OF NAOH=55.3ML,M=2.088.INTIAL TEMP FOR HCL=22.5C,NAOH IS 23C.this is for part A: Mass of final NACL solution assuming that the density of a 1 M Nacl solution is
  39. chemistry

    explain inside a flashbulb are the 2 reactants necessary for a violent reaction that produce light yet they don't react..
  40. Chem!!

    The value of ƒ¢H‹ for the reaction below is -482 kJ. Calculate the heat (kJ) released to the surroundings when 12.0 g of CO(g) reacts completely. 2CO(g) + O2(g) ¨ 2CO2(g)
  41. chemistry

    A plot of ln k vs. 1/T for the reaction gave a line with a slope - 3250 kelvin determind the energy of activation?
  42. Chemistry

    Do chemists speed a reaction by using bunsen burners or steam baths because this lowers the activation barrier?
  43. Chemistry

    How many grams of dichloromethane result from reaction of 2.62 kg of methane if the yield is 43.5 %? CH4+2Cl -> CH2Cl2+2HCl
  44. chemistry

    In the reaction of sodium metal with oxygen gas, the formula of the product will be ______________. Periodic Table
  45. Chemistry

    Write the net ionic equation for the precipitation reaction between ammonium sulfide and cadmium nitrate.
  46. Chemistry

    Write the net ionic equation for the precipitation reaction between ammonium sulfide and cadmium nitrate.
  47. Science HELP!

    The body's reaction to information is to send these to the brain. A. Neurons B. Impulses C. Dendrites D. Synapse Is the answer B? Thanks
  48. chemistry

    what is the volume in liters in H2gas produced at 24 degree celsius and 835 mmhg from the reaction of 12g of many thanks
  49. Chemistry

    When the oxidation-reduction reaction shown here is balanced, how many electrons are transferred for each atom of copper that reacts? Ag^+ + Cu = Ag + Cu^2+
  50. english

    How might readers react if the topic sentences in an essay did not coincide with the supporting points, and why would their reaction be justified?
  51. chemistry

    Consider the reaction 3CH4(g)= C3H8(g)+ 2H2(g). Using data from Appendix C in the textbook, calculate delta G at 298 K.
  52. Chem 104

    The reaction of 2.30g N2 with excess H2 produces 2.00g NH3. The percent yield of this reaaction is?
  53. chemistry

    for a reversible reaction if the concentration of reactant are doubled aad a definate tempreture then equilibrium constant will
  54. physics

    Write down a half-reaction that explains the change that occurs on the surface of the copper spoon during electrolysis.
  55. chemistry

    balance the following equation by half reaction method in an acidic medium: C3H8O + MnO4^- gives off C3H6O + Mn^2+
  56. AP Chemistry

    For the reaction 2C6H6+15O2 =12CO2+6H2O, what is the maximum amount of CO2 which could be formed from 5.12 g of C6H6 and 12.28 g of O2?
  57. chemistry

    Write a balanced equation showing the solubility equilibrium reaction of solid calcium hydroxide??
  58. chemistry

    How many moles of oxygen can be obtained by the decomposition of 7.5 mol of reactant in the following reaction? 2KClO3 -> 2KCl + 3O2
  59. Chemistry

    The rate constant for this first order reaction is 0.0470 s-1 at 400 C. A TO Products After how many seconds will 11.0% of the reactant remain?
  60. Chemistry

    Enter the net ionic equation, including phases, for the reaction of AgNO3(aq) with BaO(aq). Is it... Ag+O2--->AgO?
  61. Chemistry

    Write an equilibrium reaction equation for each of the following buffer mixtures: a)NH3(aq) and NH4Cl(aq) b)HC7H5O2(aq) and NaC7H5O2(aq)
  62. Science

    Write the word equation to show the chemical reaction taking place during acid rain?
  63. chemistry

    HOw many calories of heat were produced by the reaction of 10ml water with the powder of two compartments (2x3.23 g) of the heater?
  64. chemistry

    How do you write a balanced equation for the preparation of phenylmagnesium bromide and it's reaction with benzophenone followed by neutralization in acid?
  65. Chemistry

    Write the equation for the reaction by which aspririn decomposes in an aqueous ethanol solution. C9H8O4 + C2H6 --> ?
  66. Chemistry

    The rate constant for this first order reaction is 0.0470s-1 at 400 C. A to products After how many secs will 11.0% of the reactant remain?
  67. Chemistry

    What mass of calcium carbonate reaction with hydrochloric acid yields 44L of the gas at 27 ° C and 1520 mm Hg?
  68. chm152

    At a particular temperature, Kc = 54 for the reaction H2(g) + I2 (g) <=> 2 HI(g). One mole of HI is placed in a 3.0-L container. What would be the equilibrium concentration of HI? Choose one answer. a. 0.035 b. 0.071 c. 0.29 d. 0.30 e. 0.33
  69. chemistry

    write and equation for the reaction of triethylamine and water. does the eqilibrium go to the right or left. so far what I have is C6H15N + H2O but I'm not sure of the products
  70. Chemistry

    What would the reaction of these two look like (reactants and products) A) hexanal is reduced B) Butanoic acid is neutralized by potassium hydroxide
  71. Chemistry

    Please help me answer the question: What does it mean Write a net ionic equation for the reaction 2HCl + Ca(OH)2 -> CaCl2 + 2H20
  72. SCIENCE

    CAN WE USE A COPPPER VESSEL FOR STORING 1 MOLAR AgNO3 SOLUTION? IF NO JUSTIFY BY GIVING CHEMICAL REACTION BETWEEN THEM
  73. Chemistry

    Calculate the grams of NaNO3 required to produce 5L of oxygen at STP if the percent yield of the reaction is 78.4%?
  74. chm152

    Consider the equilibrium of water with gaseous hydrogen and oxygen: Give the value of for this reaction, if it is written as: Choose one answer. a. -7.8 x 10^-16 b. -3.9 x 10^-16 c. 1.3 x 10^-15 d. 6.4 x 10^-14 e. 3.6 x 10^2
  75. Chemistry

    Balance the following equation for a half reaction that occurs in acidic solution. Use e– as the symbol for an electron. Mo^3+ -> MoO2^2+
  76. Chemistry

    A(n) ____ reaction is one in which oxygen reacts with another compound to form carbon dioxide, water, and heat.
  77. chemistry

    In the redox reaction: 4NH3(g)+3O2(g)-->2N2(g)+6H2O(l) the number of moles of electrons transferred is...
  78. chemistry

    what mass of salt can be produced from the reaction of 3.45 grams of sodium hydroxide and an excess of hydrochloric acid?
  79. Chemistry 1002

    Calculate the standard entropy change for the following reaction at 25 °C. 2 Al (s) + 3 ZnO (s) --> Al2O3 (s) + Zn (s) answer is in J/K mol
  80. Chemistry

    Right, for the reaction of hot sodium hydroxide plus chlorine , how come one of the products are 5NaCl and not Na5Cl seeing as we now know the oxidation state of cl is -5
  81. chemistry

    a. what is the effect on the Kc when the temperature of an exothermic reaction is lowered? b. according to Le Chatelier's principle, how is equilibrium in part a established.
  82. Chemistry

    Write the net ionic equation for the precipitation reaction between ammonium sulfide and cadmium nitrate.
  83. chemistry

    if a reaction vessel contains 11.5g NH3, 12.0g O2, and 10.5g CH4, what is the maximum mass in grams of hydrogen cyanide that could be made?
  84. chemistry 12

    what is the chemical formula for the reaction between lead acetate and potassium iodide? please show both reactants and products. :)
  85. chemistry

    Ca(s) + Br2(l) --> CaBr2 is synthesis my teacher also said that the cause of the reaction is stable electron configuration is that the same thing as the electrolytes one
  86. Chemistry

    What mass of calcium phosphate form by the reaction of 50 mL of 0.2 M H3PO4 with 80 mL of 0.1 M Ca(OH)2? 2 H2PO4 + 3 Ca(OH)2 --> Ca3(PO4)2 + 6 H20
  87. chemistry

    For the following reaction, identify the substances oxidized, reduced and the oxidizing and reducing agents? 2SO2 + O2 --> 2SO3
  88. chemistry

    given the following data: S(s)+3/2 O2(g)->SO3(g) H=-395.2 kj 2SO2(g)+ O2(g)->2SO3(g) H=-198.2kj calculate H for the reaction S(s)+ O2(g)->SO2(g)
  89. Chemistry

    Explain how conc. H2so4 catalysis the speed of the reaction between salicylic acid and acetic anhydride.
  90. i hate.."chemistry"

    write the balanced half reaction for the conversion of HOBr(aq) to Br2(aq) in acidic solution
  91. chemistry

    calculate the number of grams of co2 that can be absorbed by complete reaction with a solution that contains 5.00 g of sodium hydroxide
  92. chemistry

    what is the gas formed when baking soda is added to vinegar? complete the reaction: NaHCO3(s) + CH3COOH(aq)
  93. AP Chem

    Lead metal is added to a solution of hydrochloric acid. What would be the theoretical cell potential, E°, for the reaction?
  94. chemistry

    Determine how many milliliters of 0.255 M HClO4 will be required to neutralize 48.56 g Ca(OH)2 according to the reaction: 2HClO4(aq)+Ca(OH)2(s)=CA(ClO4)2(aq)+2H2O(l)
  95. medical language

    what are the interrelations of blood clotting, immune response, allergic reaction and hormone release.
  96. Body Systems/Terminology

    The most serious type of allergic reaction is A. atrial fibrilation B. psoriasis C. anaphylaxis D. lupus
  97. chemistry

    For the following reaction, identify the substances oxidized, reduced and the oxidizing and reducing agents? 2SO2 + O2 --> 2SO3
  98. chemistry

    what mass of salt can be produced from the reaction of 3.45 grams of sodium hydroxide and an excess of hydrochloric acid?
  99. HCA/220

    how does blood clotting, immune response, allergic reaction and hormone resonse relate to each other
  100. Gen Chem

    n = 6 and E° = 0.011v for a redox reaction with Q = 7.03 x 10-1. Calculate E. Assume T = 298.15K. How do I set this equation up?