Jin

Popular questions and responses by Jin
  1. chemistry

    Predict whether the following solutions are acidic, basic, or nearly neutral: a. NaBr, b. K2SO3, c. NH4NO2, d. Cr(NO3). the answer is neutral, basic, acidic, acidic and i am not sure why

    asked on July 4, 2010
  2. chemistry

    How do you know if these solutions are acidic, basic, or nearly neutral? a. NH4NO2 b. Cr(NO3)3

    asked on July 24, 2010
  3. chemistry

    how do you solve this problem?? What is the original molarity of a solution of formic acid (HCOOH) whose pH is 3.26 at equilibrium? the answer is 2.3 x 10^-3M.

    asked on July 4, 2010
  4. math

    If a ball is thrown straight up into the air with an initial velocity of 95 ft/s, it height in feet after t second is given by y=95t–16t2. Find the average velocity for the time period begining when t=1 and lasting (i) 01 seconds: (ii) 001 seconds: (iii)

    asked on August 11, 2010
  5. physics

    In Figure (a), a block of mass m lies on a horizontal frictionless surface and is attached to one end of a horizontal spring (spring constant k) whose other end is fixed. The block is initially at rest at the position where the spring is unstretched (x =

    asked on October 24, 2009
  6. chemistry

    lithium + gold(III) chloride +lithium chloride + gold need to balance equation

    asked on December 5, 2010
  7. math

    An open box is to be made from a flat piece of material 18 inches long and 2 inches wide by cutting equal squares of length xfrom the corners and folding up the sides. Write the volume Vof the box as a function of x. Leave it as a product of factors, do

    asked on August 11, 2010
  8. chemistry

    Write balanced equations and solubility product expressions for the solubility equlibria of the following compounds: a. CuBr b. ZnC2O4 c. Ag2CrO4 d. Hg2Cl2 e. AuCl3 f. Mn3(po4)2 can you give me some examples using the compounds given?

    asked on July 19, 2010
  9. PHYSICS

    Wile E. Coyote is holding a “HEAVY DUTY ACME ANVIL” on a cliff that is 40.0 meters high. The Roadrunner (beep-beep), who is 1.0 meter tall, is running on a road toward the cliff at a constant velocity of 10.0 m/s. Wile E. Coyote wants to drop the anvil

    asked on November 9, 2009
  10. Algebra

    For 1980 through 1990, the average weekly earnings (in dollars)for workers in the United States can be modeled by E= 14.5t + 270, where t is the number of years since 1980. Approximate the average weekly earnings in 1980 and 1990. I am having trouble

    asked on August 25, 2005
  11. Math

    How many toothpicks are needed for nth design? Explain how do you figure out.

    asked on May 18, 2018
  12. chemistry

    A salt that could decrease the ionization of HCOl in soln is probably a. NaOH b. NaCl c. NaOCl d. NaH e. none of these how would you solve this

    asked on July 27, 2010
  13. chemistry

    To have a color, the transition metal complex should have an electron in a d-orbital, and an unoccupied spot in a higher energy d-orbital. • Practice Problem. • Predict whether each of the following complexes could be colored: (a) [Sc(H2O)6]3+ (b)

    asked on July 27, 2010
  14. chemistry

    Determine the oxidation state of each transition metal in the following cmpds. (a) Na2MoO4 (b) KAuCl4 (c) MgWO4 and (d) Ni(CO)4

    asked on July 27, 2010
  15. chemistry

    how do you solve this? The candy indistry converts sucrose (C11H22O11,table sugar),a crystalline material, to invert sugar, a hydrolzyed [rpdict tjat os 50:50 frutose and glucose. The hydrolysis occurs in water, quite slowly, at an elevated temperature of

    asked on July 27, 2010
  16. chemistry

    I had this on a test, not sure how to do it Explain, using balanced chemical reactions with the smallest integer coefficients, why each of following occurs. a. CuI2 (insoluble in pure water) dissolves readily in aqueous ammonia, HN3(aq) b. AgBr (insoluble

    asked on July 24, 2010
  17. chemistry

    Explain, with balanced ionic equations, why a. CuI2 dissolves in ammonia solution b. AgBr dissolves in NaCN solution, c. HgCl2 dissolves in KCL solution.

    asked on July 19, 2010
  18. Math

    How many toothpicks are needed for nth design? Explain how do you figure out.

    asked on May 18, 2018
  19. Statistic

    According to the CDC, 25 % of college students get the flu every year. (a) If 7 college students are selected at random? What is the probability that exactly 6 of them have the flu? (b) What is the mean and standard deviation for this distribution?

    asked on November 28, 2015
  20. Physics

    An orange rolls across a table with a speed of 0.5 m/s and falls off the edge. If it lands 3 m from the edge of the table, from what height does it fall?

    asked on March 6, 2015
  21. algebra

    A ball is thrown into the air with an upward velocity of 28 ft/s. Its height (h) in feet after t seconds is given by the function h = –16t² + 28t + 7. How long does it take the ball to reach its maximum height? What is the ball’s maximum height? How

    asked on March 26, 2012
  22. Calculus

    find all values of x for which function is differentiable. y=lnx^2 why is the answer= for all x doesn't equal 0?

    asked on October 29, 2010
  23. Calculus

    find the derivative y= csc^-1 (secx) 0 less than or equal to x less than or equal to 2¤Ð what did i do wrong? - 1/ secx sqrt(secx^2 -1) * secxtanx

    asked on October 29, 2010
  24. 9 th science

    distinguish between tolerance range and optimal range

    asked on September 13, 2010
  25. calculus

    find the domain of function f(x)= (5x + 4)/(x^2 + 3x + 2) is the answer.. x can't be -2 or -1?

    asked on August 4, 2010
  26. chemistry

    Faraday¡¯s Law of Electrolysis • Practice Problem. • What is the oxidation state of the osmium atom in an unknown salt if 26.7 grams of osmium plate out when a current of 15 amps is passed through a solution of this salt for 1 hour?

    asked on July 27, 2010
  27. chemistry

    The values of Ksp for AgBr and AgCl, are 7.7x10^-13 and 1.6 x 10^-10. A solution containing a mixture of 2.0x10^-2 M Br and 2.0 x 10^-2M Cl is a candidate for separating using selective precipitation. Solid AgNO3 is added, with a miniature spatula, and

    asked on July 24, 2010
  28. chemistry

    How do you solve this problem? In a certain industrial process involving a heterogeneous catalyst, the volume of the catalyst (in the shape of a shpere) is 10.0cm^3. Calculate the surface area of the catalyst. IF the sphere is broken down into eight

    asked on July 15, 2010
  29. chemistry

    how do you solve this problem? consider the reaction A->B the rate of the reaction is 1.6 x 10^-2 M/s when the concentration of A is 0.35 M. Calculate the rate constant if the reaction is a) first order in A and b) second order in A.

    asked on July 15, 2010
  30. chemistry

    Find the mass of liquid water required to absorb 4.81×104 kJ of heat energy on boiling. Answer in units of g.

    asked on March 17, 2020
  31. physics

    A girl with a 69.2 g yo-yo is swinging it in a horizontal circle at an angular velocity of 6.55 rad/s. If the string is tilted down at an angle of 20.4°, what must the length of the yo-yo string be?

    asked on October 25, 2019
  32. Geography

    Sailing west from England on which continent would you first make landfall?

    asked on October 20, 2018
  33. Math

    Tickets to the school play cost $4 for adults and $2 for students. If 255 adults and 382 students attended the play, write an expression that shows the total amount of money made on ticket sales. Then evaluate the expression.

    asked on October 1, 2018
  34. English

    Is "words are eaten" personification?

    asked on November 11, 2017
  35. Math

    Two tourists went on a hike at dawn. One went from a to b and another one went from b to a. They met at noon but did not stop and continued walking maintaining same speed for the whole trip. One finished his hike at 4pm in B and another one came to A at 9

    asked on October 30, 2017
  36. Calculus MATH

    Problem statement a) Suppose f(x) is defined on 0 ≤ x ≤ 1 by the following rule: f(x) is the first digit in the decimal expansion for x. For example, f(1/2) = 5 and f(0.719) = 7. Sketch the graph of y = f(x) on the unit interval with appropriate scales

    asked on November 30, 2016
  37. Economics

    Suppose that 20 workers were required in 2010 to produce 120,000 bushels of wheat on a 1,000-acre farm. a. What is the average output per acre? (?) bushels per acre What is the average output per worker? (?) bushels per worker b. If in 2020 only 16 workers

    asked on August 20, 2015
  38. math

    Draw a picture that represents 3x50=150?

    asked on March 17, 2015
  39. chemistry

    I'm working on substitution organic chemistry problems and I just had a question. There's an equation in which a molecule is treated with methanol in an acetone solution. Would the reaction be SN1 or SN2? I thought that it was SN2 because of the aprotic

    asked on November 29, 2014
  40. chemistry

    The activation energy, Ea, for a zeroth-order reaction, X-->products, is most readily obtained from the slope of a plot of: (choose from below) -[X] vs time -ln k vs time -rate vs time -[X]^2 vs time -ln[X] vs time -1/[X] vs time -ln k vs 1/T, where T is

    asked on June 18, 2014
  41. chemistry

    A reaction has a first order rate constant of (6.25x10^-5 1/s) at T=298.15K and (0.0000538 1/s) at T=338.15K. What is the value of the rate constant at T=316.15K?

    asked on June 18, 2014
  42. chemistry

    According to the mechanism below, what is the correct expression for the rate consumption of A? In the mechanism, M is a molecule that collides with A and A* is a highly-energized for of A. Step 1: A+M A*+M : rate constants k1 and k-1 Step 2: A* C : rate

    asked on June 18, 2014
  43. chemistry

    The decomposition reaction, x-->products, is second-order with rate constant k=0.0183 L/(s)(mol). How long will it take for the decomposition to be 95% complete, if the intitial concentration of X is 1.25mol/L? Thanks

    asked on June 18, 2014
  44. chemistry

    if a college student went into the lab and produced 45 grams of Na2CO3, what is percent yield of this trial?

    asked on February 25, 2014
  45. chemistry

    LAST QUESTION: When solid NH4NO3 decomposes, a mixture of gases is obtained: 2 NH4NO3(s)--> 4H2O(g) + O2(g) + 2 N2(g) In an experiment, 5.02 g NH4NO3 decomposes completely in a rigid 5.00-L container. What is the total pressure in the container if the

    asked on February 24, 2014
  46. chemistry

    It takes 19.6 mins for a 10.0mL sample of an unknown gas to effuse through a pinhole. A 10.0mL sample of He, required 5.05mins. What is the molar mass of the unknown gas? I got that you have to do : effuse rate of He/Effuse rate of Mx = Square root of

    asked on February 24, 2014
  47. chemistry

    Carbon monoxide, CO and hydrogen, H2, react accordingly: 4CO(g)+9H2(g)-->C4H10(g)+4H2O What volume of the EXCESS REACTANT remains if 17.2L CO and 42.1L H2 are allowed to react? Assume both gases are measured at 711 degree celsius and 1.33atm.

    asked on February 24, 2014
  48. chemistry

    What is the density of CH4 gas at 32.7 degree celsius and 109kPa? The molar mass of CH4 is 16.042g/mol.

    asked on February 24, 2014
  49. History

    Describe and evaluate President Eisenhower’s policy regarding Joseph McCarthy.

    asked on January 8, 2012
  50. calculus

    f(x)=8x^3+1x^2–8x+2/–7x^2–4x+9 Find the equation of the non-vertical asymptote. y = Does f(x) intersect its non-vertical asymptote? (yes or no) What is the smallest value of x at which f(x) intersects its non-vertical asymptote? ( Enter No in the

    asked on September 4, 2010
  51. calculus

    Consider the function f(x)=–3x3–1x2+1x+1Find the average slope of this function on the interval (–2–1). By the Mean Value Theorem, we know there exists a c in the open interval (–2–1) such that f(c) is equal to this mean slope. Find the value

    asked on September 4, 2010
  52. calculus

    se differential, i.e., linear approximation, to approximate (8.4)^(1/3) as follows: Let f(x)=(x )^(1/3). The linear approximation to f(x) at x=8 can be written in the form y=mx+b where m is: and where b is: Using this, we find our approximation for

    asked on August 28, 2010
  53. calculus

    The circumference of a sphere was measured to be 78.000 cm with a possible error of 0.50000 cm. Use linear approximation to estimate the maximum error in the calculated surface area. Estimate the relative error in the calculated surface area.

    asked on August 28, 2010
  54. calculus

    A street light is at the top of a 16 ft tall pole. A woman 6 ft tall walks away from the pole with a speed of 4 ft/sec along a straight path. How fast is the tip of her shadow moving when she is 40 ft from the base of the pole?

    asked on August 28, 2010
  55. math

    The horizontal asymptotes of the curve y=12x/(x4+1)^(1/4)

    asked on August 28, 2010
  56. math

    he circumference of a sphere was measured to be 78000 cm with a possible error of 050000 cm. Use linear approximation to estimate the maximum error in the calculated surface area.

    asked on August 27, 2010
  57. math

    A spherical snowball is melting in such a way that its diameter is decreasing at rate of 0.2 cm/min. At what rate is the volume of the snowball decreasing when the diameter is 12 cm. (Note the answer is a positive number).

    asked on August 27, 2010
  58. math

    How do you find the derivative of square root of five /t^5? how do you find the derivative of square root of five /t^5 I know that f=a t^-n f'= -an t^(-n-1) and i tried putting -25/{[2sqrt(5/t^5)]/(t^4)}

    asked on August 20, 2010
  59. math

    what is the derivative of f(x)=6sin2x I put 12cosx...

    asked on August 20, 2010
  60. math

    If a ball is thrown vertically upward from the roof of 32 foot building with a velocity of 80 ft/sec, its height after t seconds is s(t)=32+80t–16t2. What is the maximum height the ball reaches? What is the velocity of the ball when it hits the ground

    asked on August 20, 2010
  61. math

    If f(x)=(x^2+3x+4)^2 how do you find the derivative I tried doing 2 (2x+3)..

    asked on August 20, 2010
  62. math

    how do you find the derivative of square root of 5 /t^5

    asked on August 20, 2010
  63. math

    how do you find sin7x/4x when lim x goes to 0 the answer is 7/4

    asked on August 19, 2010
  64. math

    how does secx(tanx + tan^2x- sec^2x) simplified to sec x (tanx -1)?

    asked on August 19, 2010
  65. math

    how do you find the derivative of square root of x

    asked on August 19, 2010
  66. math

    I don't know how y-1=-1/3(x-3) is simplifes to x+3y-6=0

    asked on August 17, 2010
  67. math

    how do you find the equation of a line knowing (-5,-5) and (-2.-3) so the slope will be 2/3...

    asked on August 14, 2010
  68. math

    In the theory of relativity, the mass of a particle with velocity v is m=mo/(square root ((1- v^ 2)/ c^2)) where mo is the mass of the particle at rest and ci s the speed of light. What happens as v goes to c?

    asked on August 13, 2010
  69. math

    how do you factor our a cube? x^3 +8

    asked on August 12, 2010
  70. math

    evaluate the limit as lim h goes to 0 ((2+h)^3 - 8)/h the answer is twelve but I don't know how to factor out the cube

    asked on August 12, 2010
  71. math

    evaluate the limit as lim goes to -1 (x^2 +2x +1)/ (x^4 -1) the answer is zero but i don't know how to get it

    asked on August 12, 2010
  72. math

    if f(x)is greater or equal to 10x–42 but less than or equal to x2+2x–26 determine limx4f(x) = What theorem did you use to arrive at your answer?

    asked on August 11, 2010
  73. math

    if f(x)is greater or equal to 10x–42 but less than or equal to x2+2x–26 determine limx4f(x) = What theorem did you use to arrive at your answer?

    asked on August 11, 2010
  74. chemistry

    Rates of chemical reactions usually depend on temperature and pressure. However, half-life of all radioactive elements is independent of both T and p. How can these decay rates be independent of T if we beleive in the Arrhenius equation?

    asked on July 27, 2010
  75. chemistry

    Which of the following salts would show an appreciable pH-dependent solubility? a. AgCl b. Mg(OH)2 c. BaF d. both b and c e. all of the above I put c as my answer (not sure if its right, but can you explain how you would solve this)

    asked on July 27, 2010
  76. chemistry

    In titration of a 0.10M soln of Na2Co3 with HCL which of the following will be present in the largest concentration at the first equivalence point? a. Co3^2- b. HCO3- c. H+ d. H2CO3 e. OH-

    asked on July 27, 2010
  77. chemistry

    Which of the following when added to 100.0mL of a 0.100M soln of NH4Cl would produce a buffer soln? a.100.0mL of 0.100 M HCl soln b. 100.0mL of 0.050M NaOH soln c. 100.0mL of 0.100M NaOH soln d. 100.0mL of 0.050M NH4No3 soln e.none of the above

    asked on July 27, 2010
  78. chemistry

    why is it that [H2O] is NOT included in the rate law, even though it is a reactant?

    asked on July 27, 2010
  79. chemistry

    why is it that [H2O] is NOT included in the rate law, even though it is a reactant?

    asked on July 27, 2010
  80. chem

    7.50gram quantity of a diprotic acid was dissolved in water and made up to exactly 250ml. If 25ml of this solution were neutralized by 11.1 mL of 1.0 M KOH then what is the molar mass of the acid? I did 7.50/5.55x10^-3

    asked on July 24, 2010
  81. chemistry

    Discuss the spontaneity of an electrochemical reaction in terms of its standard emf (E¨¬cell)

    asked on July 22, 2010
  82. chemistry

    Solid NaI is slowly added to a soln that is 0.010M in Cu+ and 0.010M in Ag+. a. Which compound will begin to precipitate first? b. Calculate [Ag+] when CuI just begins to precipitate/ c. What percent of Ag+ remains in solution at this point?

    asked on July 19, 2010
  83. chemistry

    The amount of indicator used in an acid-base titration must be small. why??

    asked on July 19, 2010
  84. chemistry

    the chapter is about chemical kinetics Reaction mechanisms: What does it mean by mechanism of a reaction? What is an elementary step? what is the molecularity of a reaction?

    asked on July 15, 2010
  85. chemistry

    Determine the overall orders of the reactions to which the following rate laws apply: a) rate= k[NO2]^2 b) rate = k c) k [H2][Br2]^1/2 d) k [NO]^2[O2] is it.. a. 2 b. 0 c. 1 1/2 d. 3

    asked on July 15, 2010
  86. chemistry

    how do you solve this What is the pH of the solution created by combining 2.60 mL of the 0.10 M NaOH(aq) with 8.00 mL of the 0.10 M HCl(aq)? with 8.00 mL of the 0.10 M HC2H3O2(aq)? mL NaOH 2.60 pH wHCl: _ pH wHC2H3O2 : _ Complete the table below: What are

    asked on July 12, 2010
  87. chemistry

    how do you solve this? What is the pH of the solution created by combining 12.30 mL of the 0.10 M NaOH(aq) with 8.00 mL of the 0.10 M HCl(aq)? with 8.00 mL of the 0.10 M HC2H3O2(aq)? mL NaOH pH wHCl pH wHC2H3O2 12.30 Complete the table below: What are the

    asked on July 12, 2010
  88. chemistry

    Which reactants in the reactions below are acting as Br©ªnsted-Lowry bases? NH4 +(aq) + OH−(aq) NH3(aq) + H2O(l) H2PO4 −(aq) + H2O(l) H3O+(aq) + HPO4 2−(aq) is the answer H2O and the H3O+

    asked on July 6, 2010
  89. chemistry

    The pKa for hydrochloric acid is −6.0. What is the concentration of HCl(aq) we would expect to find in a 1 M solution of hydrochloric acid? What pH would we expect? how do you solve this problem?

    asked on July 6, 2010
  90. chemistry

    The pH of a 0.0642 M solution of a monoprotic acid is 3.86. s this a strong acid? the answer is no, can you explain why??

    asked on July 4, 2010
  91. chemistry

    how do you solve this problem?? how much NaOH (in grams) is needed to prepare 546mL of solution. What is the pOH of the solution?

    asked on July 4, 2010
  92. chemistry

    for SCN- if S-C has a bond order of 1, S=C and C=N have bond orders of 2, and C triple bond N hasa bond order of 3, ... Do the bond length in SCN- point to one resonance structure over the other? Which one?

    asked on June 30, 2010
  93. chemistry

    how do you know which bonds have a more pie bonding character than the other bond? and how do you know if it point to one resonance structure over the others?

    asked on June 30, 2010
  94. chemistry

    how do you know which resonance structure is more stable according to the energy? does higher energy mean more stable?

    asked on June 30, 2010
  95. chemistry

    The Fe(ox)33– complex ion creates an emerald green solution when dissolved. The observed solution color of the complex indicates the size of o is: A. large. B. small. C. in between. D. inconclusive, more information is needed. The observed solution color

    asked on June 30, 2010
  96. physics

    A skier leaves the end of a ramp with a velocity of 25.3 m/s and lands 50.3 m from the base of the ramp. How high is the end of the ramp from the ground?

    asked on November 9, 2009
  97. Accounting

    How does discounted cash flow differ from the other valuation methods?

    asked on January 14, 2009
  98. Middle school Engllish

    My son recently had an English test where he was marked incorrectly, but I think he was correct. I just need some verification. The question: "The whole neighborhood watched him climb in his old pickup and ______ down our street at full speed." The word to

    asked on December 16, 2008
  99. Accounting

    How does the frequency of interest compounding, regardless of the rate of interest or period of accumulation, affect the future value of any given amount?

    asked on December 15, 2008
  100. science

    Would you expect the dissolved oxygen concentration of water samples taken from a lake at 7 am to be higher or lower than samples takn at 5 pm? I feel like there may be more dissolved oxygen in the sample taken at 7 am because photosynthesis probably took

    asked on May 7, 2008

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