1. physics

    A ball was shot from the angles given in the table below. The corresponding ranges (landing at the same height from which it is shot) for three trials are given below as well. A. Determine the average range and standard deviation for each angle. B. Next
  2. Physics

    If you throw a ball through a pile of sand, it will slow down in the sand and emerge at less that its initial speed. But when light shines on a pane of glass, even though it slows down inside, its speed upon emerging is the same as its initial speed.
  3. Physics

    A ball is thrown horizontally from a height of 16.01 m and hits the ground with a speed that is 5.0 times its initial speed. What was the initial speed? This question really boggles my brain. I have no idea how to solve this, given only the height. Could
  4. physics

    A shell fired from the ground with an initial speed of 1.70 x 10^3 m/s at an initial angle of 55 degrees to the horizontal. neglecting air resistance, find a) the shell's horizontal range b)the amount of time the shell is in motion.
  5. chemistry

    A student weighed out 1.5g of salicylic acid into a flask and then added 4ml of acetic an hydride to react. He also added 5 drops of concentrated sulfuric acid. Density of acetic an hydride is 1.08g/ml and sulfuric acid is 1.85g/ml (sulfuric acid is a
  6. CHEMISTRY

    The heat evolved in the reaction of hydrobromic acid with potassium hydroxide was determined using a coffee coup calorimeter. The equation for the reaction is: HBr(aq) + KOH(aq) -------------> KBr(aq) + H2O(l) When 25.0 mL of 1.00 M HBr at a temperature of
  7. Physics

    A 5.00-kg box is suspended from the ceiling by a cord that is 50.0 cm long. A 10.0-g bullet was fired horizontally with speed at 350 m/s into the box. By how much will the vertical height of the pendulum change? Clue: To get the speed of bullet and box
  8. PHYSICS

    2.6 kg mass initial velocity of v1 =aˆi, where a = 5.95 m/s collides with and sticks to a 1.59 kg mass with an initial velocity of v1 = bˆj, where b = −4.8 m/s. Find the final speed of the composite mass. Answer in units of m/s
  9. chemistry

    A reaction mixture is in a 5.4 L flask at 25 oC initially contains only 7.64 grams of acetic acid. (CH3COOH). Set up your I.C.E. table and use it to answer the following questions. HINT: You will need to look up the Ka for this equilibrium reaction.
  10. Physics

    Problem 21.10 A proton with an initial speed of 800000 m/s2 is brought to rest by an electric field. Part B - What was the potential difference that stopped the proton? Part C - What was the initial kinetic energy of the proton, in electron volts?
  11. PHYSICS

    Given: The initial position of the block is the origin; i.e., x = 0 at t = 0 . Consider down the track to be the positive x-direction. A block with an initial velocity v0 slides up and back down a frictionless incline. Which graph best represents a
  12. physics

    Problem 21.10 A proton with an initial speed of 800000 m/s is brought to rest by an electric field. Part B - What was the potential difference that stopped the proton? = Part C - What was the initial kinetic energy of the proton, in electron volts?
  13. physics

    A 1.4-kg copper block is given an initial speed of 2.0 m/s on a rough horizontal surface. Because of friction, the block finally comes to rest. (a) If the block absorbs 85% of its initial kinetic energy as internal energy, calculate its increase in
  14. chemistry

    A reaction has a rate law, rate = kA]B]^2 What is the overall order of the reaction? a. 2 b. 3 c. 0 d. 1 e. 4 chemistry - DrBob222, Friday, February 17, 2012 at 10:53pm The overall is the sum of the orders of each component. still don't get it but guessing
  15. Chimestry

    (The reaction of calcium hydride and water produces calcium hydroxide and hydrogen as products). How many moles of H_2(g) will be formed in the reaction between 0.90mol CaH_2(s) and 1.33mol H_2O(l)?
  16. Physics

    For a certain Chemical reaction, you find that delta H = -100kJ and delta S = -200 J/K. What is the Gibbs free energy for the reaction at: (a) room temperature (b) 800 C (c) comment on whether the reactions are spontaneous or not
  17. Chemistry 101

    Which of the following will not increase the rate of a reaction? a. using a catalyst b.increasing the temperature c. decreasing the concentration of a reactant d. finding a shorter path for the reaction to take place e. increasing the kinetic energy
  18. chemistry

    what is a good experiment for investigating the influence of the size reaction-surface on the reaction tempo of a specific raection. using Cal-c vita tablets, rennies tablets and vinegar...?
  19. Chem

    What reaction(s) could happen if we left the same reaction mixture (from the conversion of dimethyl fumarate to dimethyl maleate) for 6 months in the absence of light? Use chemical eqns to explain your answer.
  20. chemistry

    Consider the following reaction:4HCl(g)+O2(g)produces 2H2O(g) + 2Cl2(g) How many molecules of Cl2 would be formed from the reaction mixture that produces the greatest amount of products? Express your answer as an integer.
  21. Chemistry

    Consider the reaction 2H2O(g) --> 2H2(g) + O2(g) deltaH = +483.6 kJ/mol at a certain temperature. If the increase in volume is 32.7 L against an external pressure of 1.00 atm, calculate deltaU for the reaction. (1 L * atm = 101.3 J)
  22. college chemistry

    The chemical reaction representing production of water gas is as follows: C(s)+H2O(l)=CO(g)+H2(g) calculate the enthalpy change in the production of 200L(at 500mmHg and 65degree celcius) of hydrogen by this reaction.
  23. chemistry

    Study the reaction. A(s) + 2BC(aq) →AC2(aq) + B2(g) ΔH = −92.0 kJ/mol Which change would increase the rate of the forward reaction? A. increasing the pressure B. adding more of A(s) C. adding water D. decreasing the temperature B?
  24. Chemistry

    The combustion of methanol (CH3OH) forms carbon dioxide and water vapor. A combustion reaction refers to a reaction of a substance with oxygen gas. What is the balanced equation?
  25. Chemistry

    50 mL of a 2.5 M solution of ammonium phosphate is added to 100 mL of 1.5 M solution of calcium nitrate. At the end of the reaction 11.2 grams of solid product were obtained. Whats the % yield of this reaction?
  26. Chemistry

    Consider the reaction 3CH_4(g)rightarrow C_3H_8(g)+ 2H_2(g). Calculate delta G at 298 K if the reaction mixture consists of 40atm of CH_4, 0.015atm of C_3H_8, and 2.3×10^−2atm of H_2.
  27. science(chem)

    How many mg of fluorenone can 0.53mol of sodium borohyride(NaBH4) reduce? ~I don't know how to get this..wouldn't I have to have a reaction equation given to me?? Well I didn't have one for the question given to me so I don't know what to do. I tried
  28. Chemistry

    The following reactions is a first order reaction with respect to nitrite ion and its rate constant is 0.0030/s. In a solution that is 10.0 M NO2-, what is the half-life of the reaction? NH4+ + NO2- -->N2 + 2H2O
  29. chemistry

    what would the written chemical reaction be to this problem? How many grams of hydrochloric acid should we use so we have exactly enough to react with 40g of sodium hydroxide? You'll need to write a chemical reaction, balance it, and then perform your
  30. Chemistry

    Consider the following unbalanced reaction. P4(s) + F2(g)---> PF3(g) How many grams of F2 are needed to produce 114 g of PF3 if the reaction has a 80.3% yield? I've worked it every way I can think, and the online grader says I am wrong. Someone plz lend me
  31. Chemistry

    Consider the reaction 2H2O(g) → 2H2(g) + O2(g) ΔH = +483.60 kJ/mol at a certain temperature. If the increase in volume is 42.7 L against an external pressure of 1.00 atm, calculate ΔU for this reaction. (The conversion factor is 1 L · atm = 101.3 J.)
  32. organic chemistry

    Instead of using 1-propanol or 2-pentanol, a student decided to conduct the same reaction you did starting with 2,4-dimethyl-3-pentanol. What product(s) would you predict for this reaction? Show a mechanism to account for any products you propose. How do I
  33. Chemistry 104

    The reaction of hydrogen peroxide, sulfuric acid and lead results in the production of lead sulfate in an acidic aqueous solution. Write the balanced equation for this reaction.
  34. Chemistry

    In the haber process for the preparation of NH3 which is given by the equilibruim? N_2_(g)+3H_2_(g) 2NH_3_(g)...... delta H= -92.38kJ State the conditions of concentrations and temperture that will favor production of NH_3_? Please help! would it be high
  35. world geo

    in 1971 the eastern part of pakistan became: A)maldives b)bangladesh C)kashmir D)** bhutan the highest concentrations of populations in south asia are found A)in the great indian desert B)in nepal C)on the deccan plateu D)**on the ganges plain
  36. Chemistry

    A chemical reaction produces 3.75 L of chlorine gas at STP. How many moles of chlorine are produced by the reaction?
  37. chemistry

    The value of Change in heat for the reaction below is -790 KJ. Calculate the enthalpy change accompanying the reaction of .95 g of S. 2S(s) + 3 O2 --> 2 SO3(g)
  38. Chemistry

    what is the balanced equation of: Combination reaction: Li2O(s)+H2O(l)-->(?) I know what a combination reaction is but I don't know how to do it when it is complex like this one.
  39. Chemistry

    Predict the reaction, if any, that would occur if Sr(NO3)2 and Na2CO3 were mixed. Would any reaction occur if HBr were added? Thank You
  40. Chemistry

    Predict the reaction, if any, which would occur if AgNO3 and KBr were mixed. Would any reaction occur if HNO3 was added? Thanks!
  41. chemistry

    predict the reaction, if any, that would occur if AgNo3 and KBr were mixed would any reaction occur if HBr was then added?
  42. CHEMISTRY

    For the reaction 3 O2(g) reverse reaction arrow 2 O3(g) If the equilibrium mixture is analyzed and [O2(g)] is found to be 3.77*10-2 M, what is the concentration of O3(g) in the mixture?
  43. chemistry

    When Cl- is added to the following reaction at equilibrium, does the reaction go in the forward direction, reverse direction, or remain unchanged? Ag-->Ag^+ + Cl^-
  44. chemistry

    Given the thermochemical equation: 2 Al(s) + 3/2 O2(g) > Al2O3(s) ΔH = -95.7 kJ find the heat of reaction, ΔH, for the following reaction: 2 Al2O3(s)> 4 Al(s) + 3 O2(g) Select one: a. -95.7 kJ b. +95.7 kJ c. -47.8 kJ d. +47.8 kJ e. +191.4 kJ
  45. Chemistry

    Consider the following unbalanced reaction. P4(s) + F2(g) PF3(g) What mass of F2 is needed to produce 212 g of PF3 if the reaction has a 84.2% yield?
  46. Chemistry

    The equilibrium constant, Kc is 3.2 x10 -34 at 25C for the reaction 2 HCl(g) H2(g) + Cl2(g). what is The equilibrium expression, Kc for the reaction
  47. CHEMISTRY

    The enthalpy change of an endothermic reaction is 8 kJ , and this reaction is spontaneous at 25 oC ,, what is the expected entropy change ? thank you a lot
  48. chemistry

    Consider the following unbalanced reaction. P4(s) + F2(g) PF3(g) How many grams of F2 are needed to produce 212 g of PF3 if the reaction has a 79.8% yield?
  49. Chemistry

    In the reaction 2A+B2 to 2AB if 0.5 moles of A and an excess of B are combined and the reaction goes to %100 completion, then how many moles of C are formed?
  50. Bioelectricity

    Na equil-v: Only sodium may cross a membrane separating two compartments. At a temperature of 28∘C, the concentrations of sodium ions are: intracellular: 100 extracellular: 485 What is the equilibrium potential? Give a numeric answer within 1%, in mV.
  51. chemistry

    Can the half cell electrochemistry experiment using a pH meter and aqueous solutions of Cu, Cu2+ and Ag and Ag+ be used to measure even lower concentrations, such as 10^-23 mol of Cu2+ or a single free copper ion in solution? Please explain.
  52. Bioelectricity

    K equil-v: Only potassium may cross a membrane separating two compartments. At a temperature of 30∘C, the concentrations of potassium ions are: intracellular: 280 extracellular: 110 What is the equilibrium potential? Give a numeric answer within 1%, in
  53. chemistry

    What are the equilibrium concentrations of H+,OH- ,(HSO3)-, (SO3)2- and Na+ in the solution that results from combining 50.0 mL of 0.200 M NaHSO3 with 50.0 mL of 0.600 M Ba(OH)2 ? Ka1 = 1.5 x 10-5 and Ka2 = 1.0 x 10-7 for H2SO3 does it matter that Ba(OH)2
  54. science very urgent help?

    Susan has heard that taking an over-the-counter ‘energy’ pill, which contains as much caffeine as a strong cup of coffee, makes people feel alert and ‘speedy’. She wonders if taking this pill will make a difference to the reaction times of people
  55. chemistry

    What would be the concentration of dinitrogen pentoxide after 6.00 X 10(2) seconds and how long would it take for the concentration of N2O2 to decrease to 10.0% of its initial value in the following equation... N2O5 to NO2 and O2 initial concentration is
  56. chemestry

    For the following reaction, 5.70 grams of hydrogen gas are mixed with excess nitrogen gas. The reaction yields 22.6 grams of ammonia. (1) What is the theoretical yield of ammonia ? ____ grams (2) What is the percent yield for this reaction ? ____ %
  57. chemistry

    1)The reaction of methane and oxygen yields carbon dioxide gas and water. The unbalanced reaction is as follows: CH4(g) + O2(g)CO2(g) + H2O(g) A. If 0.718 grams of methane are reacted, how many grams of water vapor are produced? B. If 1.621 grams CO2 are
  58. Chemistry

    How many milliliters of O2 are consumed in the complete combustion of a sample of hexane, C6H14, if the reaction produces 325 mL of CO2? Assume all gas volumes are measured at the same temperature and pressure. The reaction is 2C6H14(g) + 19O2(g) ->
  59. Chem

    A 7.50g sample of aluminum is placed in 250.0 mL of 1.80 mol/L sulfuric acid. The reaction is not nearly as vigorous as expected and produces only 427 mL of gas at 27 degrees celsius and 480 kPa pressure. Calculate the percentage Yield of the reaction
  60. Grd.10 Science

    So i did a science lab today, and i am supposed to come up with the skeleton equation for it The chemical reaction is decomposition (starting with one compound that will break off into 1 or more compounds after reaction) This is what i have so far : Cu
  61. chemistry lab (college level)

    So, this is going to be more like 2 or 3 questions. Here goes. First, what is the net-ionic reaction for Fe (III) + K4Fe(CN)6 be? I've been agonizing over this for HOURS with no answer in sight. (I don't even know what to put down as a product!) Second,
  62. Math3(Reiny Please Help)

    An object on Earth falls with an acceleration of a=9.81 m/s^2. A function exists between the height from which the object falls, the initial velocity of the object and the time the object spends in the air. h(t)= Vt + at^2 V=initial velocity. T= time. A=
  63. chemistry

    a 0.2000 grams sample of aluminum metal is added to a solution containing 1.0000grams of an unknown compound made of platinum and chloride ion. the reaction results in the formation of aluminum chloride and platinum metal. when the reaction is complete,
  64. physics

    if you fire a ball through a pile of sand, it iwll slow ddown in the sand and emerge at less that its initial speed. But when light shines pn a pane of glass, even though it slows down inside, its speed upon emerging is the same as its initial speed.
  65. physics

    a 0.5 kg ball is thrown upward with an iniatial speed of 10 m/s, what is the initial kinetic energy of the ball and the total mechanical energy assuming initial potential energy is zero.
  66. Physics

    A pendulum bob is released from some initial height such that the speed of the bob at the bottom of the swing is 1.5 m/s. The acceleration of gravity is 9.81 m/s 2 . What is the initial height of the bob? Answer in units of m
  67. introductory to physics

    A pendulum bob is released from some initial height such that the speed of the bob at the bottom of the swing is 4.0 m/s. The acceleration of gravity is 9.81 m/s 2 . What is the initial height of the bob? Answer in units of m
  68. Chemistry Dr. BOB

    I don't get it!! In winemaking, the sugars in grapes undergo fermentation by yeast to yield CH3CH2OH and CO2. During cellular respiration, sugar and enthanol are "burned" to water vapor andCO2. Write a combustion reaction for ethanol. I need help with
  69. Chemistry

    HCl (aq) + NaOH (aq) -> NaCl (aq) + H2O (l) Will the neutralisation reaction be endothermic or exothermic? Hint: think about the net ionic equation. So, taking the hint, I got: OH- + H+ -> H2O Not sure how that helps, and now I'm stuck; how would I figure
  70. Chemistry

    What causes a reaction to be spontaneous? Answer by answering each part a) (1 point) What is definition of spontaneous reaction?b) (1 point) What is Gibbs free energy?c) (1 point) How is Gibbs free energy related to a spontaneous reaction?d) (1 point) What
  71. Chemistry

    2. Aluminum metal reacts with zinc(II) ion in an aqueous solution by the following half-cell reactions: Al(s) → Al3+(aq) + 3e− Zn2+(aq) + 2e− → Zn(s) a. Predict the potential of the cell under standard conditions. (4 points) b. Predict whether the
  72. chem!

    Calculate the heat of reaction for the incomplete combustion of 67.0g propane producing carbon monoxide gas and water vapour. how would I go about and do this question? What are you studying? Do you know how to use the thermodynamic tables (delta Ho, etc).
  73. chemistry(check my work)

    The initial pressure for the compounds involved in the reaction displayed were determined to be P(SO2(g)) = 0.5932 atm, P(O2(g)) = 0.4886 atm, P(SO3(g)) = 0.09287 atm. Calculate the value of the equilibrium constant (Kp) at 1000 K if the equilibrium
  74. Chemistry

    HELP£¡ can someone find identify one chemical reaction that C4H4O4 is involved in. Or the synthesis of the compound? C4H4O4 is a formula that applies to both maleic and fumaric acid. A synthesis reaction of reaction of maleic acid is: Maleic acid
  75. Chemistry

    What is the net chemical equation of: Reaction 1: 3.3 kcal/mol+glucose+Pi --> glucose-6-phosphate+H2O Reaction 2: ATP+H2O --> ADP+Pi+7.3 kcal/mol AND Calculate the amount of energy released in the coupled reaction. energy released: ____kcal/mol
  76. chemistry

    Consider the following reaction. 2KClO3(s) → 2KCl(s) + 3O2(g) a. How many grams of KCl are produced from the complete reaction of 2.16 mol of KClO3? 161g b. How many grams of KCl are produced from the complete reaction of 52.7 g of KClO3? 32.1 g
  77. physics

    Calculate the range of the projectile using the initial speed and angle. Use g = 9.8m/s your calculation. Initial speed is 18m/s Angle is 75 Help please !!
  78. chemistry BOB

    is this the answer to B ) CH3CH2OH + 3O2 → 2CO2 + 3H2O In winemaking, the sugars in grapes undergo fermentation by yeast to yield CH3CH2OH and CO2. During cellular respiration, sugar and ethanol are "burned" to water vapor andCO2. Write a combustion
  79. physics

    I need help understanding these, please. Thanks! 1. A 2 kg body moves with constant velocity when a force of 10 N is applied. What is the coefficient of kinetic friction between the table and the body? (Would I use F=m*g for this??) 2. Which of the
  80. chem class

    Consider the following reaction at equilibrium: 2NH3 (g) N2 (g) + 3H2 (g) ΔH° = +92.4 kJ Le Cha ^ telier's principle predicts that increasing the temperature will shift the reaction to the. a) stays same b)leftc)none d)right i was told right by some
  81. Physical Science

    An iron fence is left unpainted, and it reacts with the oxygen in the air, forming rust. The formation of rust is an oxidation-reduction reaction, but it is also an example of a(n) _________ reaction My answer is synthesis
  82. Chemistry

    When a mixture of 10.0 g of acetylene and 10.0 g of oxygen is ignited, a complete combustion of the reactants takes place. What is the limiting reagent of this reaction? How many grams of each of the reactants and products are present at the end of the
  83. chemistry

    Consider the following reaction at equilibrium: 2NH3 (g) N2 (g) + 3H2 (g) ΔH° = +92.4 kJ Le Cha ^ telier's principle predicts that increasing the temperature will shift the reaction to the. a) stays same b)leftc)none d)right i was told right by some
  84. Chemistry

    What type of reaction occurs when potassiumbromide solution is mixed. With lead(II) acetate solution? Gas evolution, oxidation reduction, precipitation, acid-base neutralization, or no reaction
  85. organic chem

    what are some chemical reasons that might have resulted in a lower yield of a product on a grignard reaction. Something related to grignards being very reactive and since its the limiting reagent, any reaction that destroys it will result in a hit in
  86. chemistry

    Consider the combustion reaction: C3H8 (g) + 5 O2(g) ---> 3 CO2(g) + 4H2O(g), where triangle symbol H= - 531 kcal/mol. If 6.70 x 10 to the 4th kcal of energy is released in the reaction, How many grams of oxygen were consumed
  87. Chemistry

    The Energy from glucose is obtained from the oxidation reaction C6H12O6 + 6O2 --> 6CO2 + 6H2O How would a similar reaction look for Sucrose? I am trying to find an equation about how the body uses a compound, in this case sucrose. I'm just not sure how
  88. Organic Chemistry

    When performing a dehydration reaction, what may be done to drive the equilibrium to the right: A. removal of the product as it is formed B. increasing the concentration of the solvent C. doubling the concentration of the acid catalyst D. lowering the
  89. Chemistry (redox reaction)

    Which reaction is a redox reaction? 1. HCI+H2O=H3O^+ +CI^- 2. H2SO4+2KOH=K2SO4+2H2O 3. CH4+2O2=CO2+2H2O 4. Fe^2+ +2OH^- =Fe(OH)2 I chose number 3, is this correct?
  90. chemistry

    For the reaction Al (s) + 3 HCl (aq) à AlCl3 (s) + ₃/₂ H2 (g), it was observed that when 4.00 g of aluminum reacted with excess HCl, exactly 30.0 kJ of heat were released. The DHo for this reaction is a) – 91.3 kJ b) – 120 kJ c) – 202 kJ d) –
  91. chemistry

    A laboratory instructor gives you a test tube containing Ag+ ,Ba 2+ , and Cu 2+ ions. Devise a reaction scheme that would allow you to selectively precipitate each of these ions. Write a balanced net ionic equation for each precipitation reaction.
  92. Chem Titration and pH

    Calculate the pH at 0mL, 5mL,...40mL for a 10.0mL aliquote of 0.100M Na3AsO4 (weak base) titrated with 0.100M HCl pKa1 = 2.25 pKa2 = 6.77 pKa3 = 11.60 Thank you First you should write equations to know where we are in the titration. At the beginning, we
  93. chemistry

    The equilibrium constant for the reaction Cu3(PO4)2(s)    3 Cu2+(aq)  +  2 PO43–(aq) is K = 1.40 x 10–37.  Suppose that a beaker is filled to 1 L with a solution containing [Cu2+] = [PO43–] = 10.0 nM, and 300.0 g Cu3(PO4)2 . Which of
  94. The Nature of Chemical Reactions

    1. Molarity is to moles of solute over liters of solution as molality is to A. molar concentration over molal concentration. B. moles of solute over kilograms of solvent. C. molal concentration over molar concentration. D. moles of solute over moles of
  95. Chemistry..

    1.What is going on at the atomic level if a precipitate forms in a double replacement reaction? 2. Has a single or double replacement reaction occured if water or a gas is formed? What would you perceive as evidence that a reaction has occured if either
  96. Chemistry

    Is the following reaction spontaneous at 25*C? delta s reaction = -217 J/K*mol delta H rxn = -1202 KJ 2Mg (s) + O2 (g) -> 2MgO (s) delta suniverse = delta s system - delta H system / T i got positive (+) 3.81 x 10 ^ 3 J/K and my notes says it is
  97. general chemistry

    . The thermal decomposition of dinitrogen pentoxide in the gas phase to give nitrogen dioxide and oxygen is a first order reaction. If the half life at 55 °C is 410 s, what is the value of the rate constant k? If the initial concentration of dinitrogen
  98. chemistry

    The thermal decomposition of dinitrogen pentoxide in the gas phase to give nitrogen dioxide and oxygen is a first order reaction. If the half life at 55 C is 410 s, what is the value of the rate constant k? If the initial concentration of dinitrogen
  99. general chemistry

    . The thermal decomposition of dinitrogen pentoxide in the gas phase to give nitrogen dioxide and oxygen is a first order reaction. If the half life at 55 °C is 410 s, what is the value of the rate constant k? If the initial concentration of dinitrogen
  100. u of s

    A black thin-walled cylindrical can, 10.0 cm in diameter and 20.0 cm tall is filled with water at 100°C and suspended in a 20°C room. Determine the initial rate of heat transfer due to radiation, and the initial rate of change of temperature of the