1. Chemistry

    Define the-half of a reaction. Explain on the molecular level why the half- life of a first-order reaction is constant
  2. Chem: Two questions

    Identify the two types of reactions: 1. A+B--> Answer: Synthesis Reaction 2. A+BC-->AC+B Answer: Single Replacement or Substitution Reaction THANK YOU !
  3. Chemistry

    What property of the following reaction might be qualitatively measured to follow the rate of reaction? A) C(s) + H20(g) > H2(g) + CO(g) B) Cu(s) + 2Ag+(aq) > Cu2+(aq) + 2Ag(s)
  4. Chemistry

    A reaction A(aq)+B(aq)C(aq) has a standard free-energy change of –3.35 kJ/mol at 25 °C. What are the concentrations of A, B, and C at equilibrium if, at the beginning of the reaction, their concentrations are 0.30 M, 0.40 M, and 0 M, respectively?
  5. College Chem.

    How much energy is evolved during the reaction of 48.7 g of Al, according to the reaction below? Assume that there is excess Fe2O3. Fe2O3(s) + 2 Al(s) → Al2O3(s) + 2 Fe(s), ΔH°rxn = -852 kJ
  6. Chemistry

    For a certain reaction, ΔH° = –76.8 kJ and ΔS° = –225 J/K. If n = 3, calculate E° for the reaction at 25°C.
  7. Chemistry

    Delta H reaction for the following reaction: C(s)+H2O(g)=>CO(g)+H2(g)
  8. Chemistry

    Please help! If equal volumes of the following are combined, would they form buffered solutions? Why or why not? .1M HF and .05M NaF I'm am a bit confused about how I can figure out if these will form buffers or not, so I'd really appreciate it if someone
  9. optics

    Transpose the prescription -0.75DS/-3.25DCx30 to the toric form with a capstan-form surface which has a +2.50D base curve I have had a look at that website but still struggling
  10. math

    Find equation of the line that passes through the points (2/3,-5/4) and (-3,-5/6). write your answer in slope-intercept form and standard form with integer coefficients.
  11. math

    multiply 3 1/6 x 9/11 x 6/17 and write it in its simplest form would that make the answer 513/561? then to break it down into it simplist form it would be 171/187 correct?
  12. Chemistry

    calculate the minimum number of grams of C3H8(g) that must be combusted to provide the energy necessary to convert 3.36 kg of H2O from its solid form at -10.0°C to its liquid form at 80.0°C
  13. math

    Find the equation of the line that passes through the points (2/3, -5/4)and (-3, -5/6). Write the answer in slope-intercept form and standard form with integer coefficients. Thank you.
  14. math

    Find equation of the line that passes through the points (2/3,-5/4) and (-3,-5/6). write your answer in slope-intercept form and standard form with integer coefficients.
  15. Chemistry

    If equal volumes of the following are combined, would they form buffered solutions? Why or why not? .1M HF and .05M NaF I'm am a bit confused about how I can figure out if these will form buffers or not, so I'd really appreciate it if someone could explain
  16. Chemistry

    Acetylene, C2H2, can be converted to ethane, C2H6, by a process known as hydrogenation. The reaction is: C2H2(g) + 2H2(g) === C2H6(g) Given the following, what is the Kp for the reaction? C2H2(g): 209.2 ΔG˚f (kJ/mol) H2(g): 0 ΔG˚f (kJ/mol) C2H6(g):
  17. Chemistry

    Hydrogen is generated by passing hot steam over iron, which oxidizes to form Fe3O4, in the following equation: a. if 625 g of Fe3O4 is produced in the reaction, how many moles of hydrogen are produced at the same time? b. how many moles of iron would be
  18. Chemistry - Stoichiometry

    Elements X and fluorine react to form two different compounds. In the first reaction 0.480g of X reacts with 1.000g of F. In the second, 0.960g of X reacts with 1.000g of F. Which are possible formulas for the two compunds First Compound Second Compound
  19. science(chem)

    For the reaction: acetic acid (2g) + Isopentyl alcohol (0.9g) => Isopently acetate(1.15g)+ H2O I'm suposed to determine the limiting reagent, theoretical yield and percent yield from this reaction but the reaction was given as a picture... I'm not sure
  20. math,correction

    Find the area of the rectangle shown in the figure. length = radical (3) + radical (5) width = radical (3) + radical (5) My answer: a= 8 + 2 radical (15) or a = 15.75 agree, you seem to be able to do these should i leave it as the radical form or the
  21. Grade 9th

    If 6.5g of zinc reacts with 5.0g of HCL,according to the reaction.Zn + 2HCL:zncl2+h2 Which substance is the limiting reaction? How many grams of the reactant remains unreactant? How many grams of hydrogen would be produce?
  22. science

    For the following reaction if the reaction temperature was increased would the equilibrium shift to the right or the left,not shift at all,or you cant answer the question because Keq is not given? 2SO3(g)2SO2(g)+O2(g)..(deltaH degrees =198kj) Why???
  23. Chemistry

    Consider the following reaction: CaCO3(s)→CaO(s)+CO2(g). Estimate ΔG∘ for this reaction at each of the following temperatures. (Assume that ΔH∘ and ΔS∘ do not change too much within the given temperature range.) A) 310K B) 1070K C) 1470K And is
  24. chemistry

    For a particular chemical reaction, the rate constant at 30.0 °C is 1.38 X 10-4 L mol-1 s-1, while the value at 49.0 °C is 1.21 X 10-3 L mol-1 s-1 . What is the activation energy for this reaction? a. 92.8 kJ b. 200 kJ c. 40.4 kJ d. 343 kJ e. 56.4 kJ ln
  25. College Chemistry

    Consider the reaction. 4Fe(s) + 3O2(g) ¨ 2Fe2O3(s) If 0.500 mol of Fe reacts with 0.400 mol of O2, what are the limiting reactant and the theoretical yield in moles of Fe2O3 for the reaction, respectively?
  26. Chemistry

    Problem: In a first order decomposition reaction, 50% of a compound decomposes in 10.5 minutes. What is the rate constant of the reaction? The solution my professor gave says: k = .693 / 10.5min Where did the .693 come from? Thanks
  27. Chemistry

    125.0g each of two solids, lead (II) nitrate and pottassiuk iodide are dissolved in the same beaker. A reaction occurs that produces a precipitate. How many grams of precipitate are produced in the reaction?
  28. chemistry

    Consider the equilibrium reaction CO(g)+H2O(g)⇋CO2(g)+H2(g) Determine how each change in the left-hand column will stress the system and in which direction the equilibrium reaction will shift in response.
  29. Chemistry

    In the following reaction, 451.4 g of lead reacts with excess oxygen forming 313.6 g of lead(II) oxide. Calculate the percent yield of the reaction. 2Pb(s)+O2(g)= 2PbO(s)
  30. Chemistry

    a chemist carries out the reaction of 0.250 mol of f2 with excess of cl2. At 250 degress C and 1.00 atm, what is the maximum volume of CLF3 in liters that the reaction can produce?
  31. science

    Using your reaction time, estimate the diestance a car would travel at 20m/s (45 mi/h) before you could apply the brakes. To get the deistance in meters you multiply the speed in m/s by your reaction time in seconds
  32. Chemistry

    Consider the following reaction: CO(g)+2H2(g)⇌CH3OH(g) Kp=2.26×104 at 25 ∘C. Calculate ΔGrxn for the reaction at 25 ∘C under each of the following conditions. A) Standard Conditions B) at equilibrium C)PCH3OH= 1.3atm ; PCO=PH2= 1.2×10−2atm
  33. Chemistry

    Consider the reaction A ==> B. If the reaction is first-order in A with the initial concentration A being 6.048M, what is the concentration of A after 1.986 seconds if the rate constant is 0.483s-1? Error tolerance: ±0.5% Can someone explain how to do
  34. Chemistry

    Consider the reaction 2 SO2 + O2 in equilibrium with 2 SO3 . At 25°C Ho = -197.78 kJ and So = -187.95 J/K. Using this information, calculate the equilibrium constant for the reaction at 50°C. (R = 8.314 J/K) Enter your answer using TWO significant
  35. Chemistry URGENT!

    If the reaction of 0.500 grams of aluminum metal with excess aqueous HCl releases 9.72 kJ of heat, what is the ΔH value for the reaction? 2 Al(s) + 6 HCl(aq) → 2 AlCl3(aq) + 3 H2(g) All I have is: .500gAl*(1 mol Al/26.98gAl) Please and thank you so
  36. Chemistry

    I have this question as a review question: The reaction N2(g)+3H2(g)2NH3(g) begins with 1.15 M N2 and 1.36 M H2. At equilibrium, the concentration of NH3 is 0.78 M. Determine the extent of reaction. The answer is supposed to be 86 but I don't know how
  37. chemistry

    What is the oxidizing agent in the following reaction? Sn(s) + 2HCl(aq) → SnCl2(aq) + H2(aq) HCl H2 Sn SnCl2 . Question 2 The following is an oxidation-reduction reaction: H2CO3(aq) → CO2(g) + H2O(l) True False
  38. chemistry

    The correct interpretation of the equation below is: Fe3+(aq) + SCN–(aq) --> and
  39. chemistry

    The correct interpretation of the equation below is: Fe3+(aq) + SCN–(aq) --> FeSCN2+(aq) A. At equilibrium, the rate of the forward reaction equals the rate of the reverse reaction. B. The equilibrium constant is Kc = [Fe3+][SCN–][FeSCN2+] C. A
  40. Chemistry

    Name four factors that can affect the rate of a chemical reaction. How does the rate of a chemical reaction change in response to a change in each factor? My answer: Four factors that can affect the rate of a chemical reaction are concentration, surface
  41. science, chemistry

    Lead metal is added to 0.150 M Cr3+(aq). Pb(s)+2Cr3+(aq)⇌Pb2+(aq)+2Cr2+(aq). KC=3.2×10−10 What is [Pb2+] when equilibrium is established in the reaction? What is [Cr2+] when equilibrium is established in the reaction? What is [Cr3+] when equilibrium
  42. Equilibrium concentrations, please help!!!

    Lead metal is added to 0.150 M Cr3+(aq). Pb(s)+2Cr3+(aq)⇌Pb2+(aq)+2Cr2+(aq). KC=3.2×10−10 What is [Pb2+] when equilibrium is established in the reaction? What is [Cr2+] when equilibrium is established in the reaction? What is [Cr3+] when equilibrium
  43. Chemistry

    I posted this before and I know now to use P1T2=P2T1 but I was wondering what I would plug in as pressure and temp? just an example of one would be so great. In each of the four problem in this section, all gases are measured at the same temperature and
  44. Chem

    I really appreciate the help you gave me earlier. I was wondering if you could please look over these questions for me to? The answers will always be either reactant, product or neither. 1)P4(s)+6 Cl2(g)4 PCl3(l) Which side of the reaction will be favoured
  45. algebra

    can someone explain the benefits of writing a quadratic equation in vertex form and benefits of writing a quadratic equation in standard form? Name specific methods you can use while working with one form or the other. Any help will be appreciated.
  46. politics

    What was the White House reaction to Lesley Stahl’s critical report on Reagan’s use of television? A. CBS News was excluded from White House press conferences. B. Stahl was honored at a White House ceremony. C. The reaction was very positive, because
  47. Chemistry (equilibrium)

    In the following equilibrium system, N2O4(g) NO2(g), what happens to the color of the gas if the forward reaction speeds up? What happens if the reverse reaction speeds up? What happens if the forward and reverse reaction happen at the same time? NO2 is a
  48. Chemistry

    For the reaction 2CH3OH + 3O2 → 2CO2+ 4H2O, what is the maximum amount of CO2 which could be formed from 13.97 g of CH3OH and 5.45 g of O2? Answer in units of g. Consider the reaction H3PO4 + 3NaOH → Na3PO4 + 3H2O. How much Na3PO4 can be prepared by
  49. Into. Chemistry

    I'm trying to do this precipitation reaction problem, but I don't understand part of it. The question is: Does a precipitate form when aq. soultions of potassium nitrate (KNO3) and sodium iodide (NaI) are mixed? Then it lists the solutions for the two:
  50. Math

    The standard form of a circle is Ax^2+Cy^2+Dx+Ey+F=0. Write the equation for the circle: Center (1,2), point on the circle (-2,-1). Okay, I've always put circles in the form (x-h)^2+(y-k)^2=0. I got this: r^2=(x-1)^2+(y-2)^2 then I substitute the point to
  51. 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
  52. 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
  53. CHEMISTRY PLEASE HELP

    For the reaction A + 2B + C ----> 2 D + E the following initial concentration and initial reaction rates are found: [A]null (M) [B]null (M) [C]null (M) 0.150 0.150 0.150 0.275 0.150 0.150 0.275 0.564 0.150 0.150 0.314 0.253 0.193 0.314 0.217 initial rate
  54. AP CHEM

    For the reaction A + 2B + C ----> 2 D + E the following initial concentration and initial reaction rates are found: [A]null (M) [B]null (M) [C]null (M) 0.150 0.150 0.150 0.275 0.150 0.150 0.275 0.564 0.150 0.150 0.314 0.253 0.193 0.314 0.217 initial rate
  55. Algebra

    1) what is the degree of the monomial 3x^2y^3 A)2 B)3 C)5 D)6 2. What is the simplified form of 8b^3c^2 + 4b^3 c^2 A) 12bc B)12b^3c^2 C) 12b^6 c^4 D) 12b^9c^4 3. What is the simplified form of (4j^2+6)+(2j^2-3) A) 6j^2-3 B) 6j^2+3 C) 6j^2 + 9 D) 4j^4+3 4.
  56. English Expressions

    You should not be confused by (at ) the plural form in an adjective phrase or in an adjective clause. Just ignore the adjective phrase or the adjective clause. Then find the subject of the sentence. You can find a suitable verb form in the blank. By
  57. 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.
  58. 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.
  59. 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
  60. 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...?
  61. 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
  62. 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.
  63. 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)
  64. 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)?
  65. 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
  66. 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
  67. 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
  68. Chemistry

    Which of the following has no effect on the rate ofa reaction? a)degree of branching or size of reactant molecules b)value of Heat of reaction c)presence of a catalyst d)temperature of the reactants e) concentrations of the reactants
  69. 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?
  70. Chemistry

    If the initial rate of reaction is observed to increase by a factor of nine when the concentration of a reactant is tripled, what is the order of reaction with respect to that reactant? a)0 b)1 c)2 d)3 e)5 I think it's c am i right? Explain in case i'm
  71. 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
  72. 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.)
  73. 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?
  74. 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.
  75. Rate Laws

    If the initial concentration of AB is 0.210 M, and the reaction mixture initially contains no products, what are the concentrations of A and B after 75 s? The reaction is in the second order: rate=k[AB]^2 The rate constant is k=5.4*10^2 M*s I don't
  76. 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?
  77. 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.
  78. 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
  79. 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
  80. 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.
  81. 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
  82. 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?
  83. 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?
  84. 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)
  85. 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?
  86. 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^-
  87. 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.
  88. chemistry

    predict the reaction, if any, that would occur if AgNo3 and KBr were mixed would any reaction occur if HBr was then added?
  89. 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
  90. Chemistry

    Predict the reaction, if any, which would occur if AgNO3 and KBr were mixed. Would any reaction occur if HNO3 was added? Thanks!
  91. 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
  92. Chemistry

    A chemical reaction produces 3.75 L of chlorine gas at STP. How many moles of chlorine are produced by the reaction?
  93. 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?
  94. 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
  95. 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
  96. Chemistry

    Ok so I realize this is a lot of questions, but if someone could at least just give me the general set up for each problem that would save my life! In each of the four problem in this section, all gases are measured at the same temperature and pressure. 1)
  97. Chemistry

    If equal volumes of the following are combined, would they form buffered solutions? Why or why not? 1) .1M NaC2H3O2 and .1M HF 2) .1M HF and .05M NaF I'm am a bit confused about how I can figure out if these will form buffers or not, so I'd really
  98. english

    Which of these is true of the novel form when it was first introduced? 1.Its status as an art form was questioned. 2.It appealed to the highly educated. 3.It was nonfiction rather than fiction. 4.It satirized the working class. i think its 2? am i right?
  99. chemistry

    statement that is wrong about transition elements is 1) they have fixed oxidation states 2) they show paramagnetic behavior 3) they form interstitial compounds 4) they form complexes
  100. 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 ? ____ %