Most popular questions and responses by kb
  1. Chemistry

    Calculate the pH for each of the following points in the titration of 50.0 mL of a 2.7 M H3PO3(aq) with 2.7 M KOH(aq). pKa1 = 1.3 and pKa2 = 6.7 a) before addition of any KOH b) after addition of 25.0 mL of KOH c) after addition of 50.0 mL of KOH d) after

    asked on March 11, 2013
  2. Chemistry

    Calculate the pH at the equivalence point for the titration of 0.200 M methylamine (CH3NH2) with 0.200 M HCl. The Kb of methylamine is 5.0× 10–4.

    asked on March 11, 2013
  3. English

    Identify the correct sentence. A. In my top drawer is a birthday card from my grandmother and a gold watch from my mother. B. In my top drawer are a birthday card from my grandmother and gold watch from my mother. C. In my top drawer are a birthday card

    asked on January 25, 2017
  4. chemistry

    A mixture of carbon and sulphur has a mass of 9.0 g. Complete combustion with excess oxygen gives 22.6 g of a mixture of carbon dioxide and sulphur dioxide. Find the mass of sulphur in the original mixture

    asked on September 22, 2011
  5. Chem

    What is the longest wavelength of electromagnetic radiation capable of ionizing this hydrogen atom in an excited state? Report your answer in nanometers. Δ𝐸=−2.178×10−18 J(1𝑛2final−1𝑛2initial)

    asked on April 30, 2019
  6. English

    __________ Destiny or Caroline sent an RSVP to the invitation? We __________ everyone __________ it to Jake's party. A. Has; hope; make B. Have; hopes; make C. Have; hope; makes D. Has; hope; makes I say C

    asked on January 25, 2017
  7. physics

    A 45 kg skater is standing still in front of a wall. By pushing against the wall she propels herself backward with a velocity of -1.0 m/s. Her hands are in contact with the wall for 0.80 s. Ignore friction and wind resistance. Find the magnitude and

    asked on October 14, 2008
  8. physics

    A mine car, whose mass is 590 kg, rolls at a speed of 0.5 m/s on a horizontal track, as the drawing shows. A 150 kg chunk of coal has a speed of 0.95 m/s when it leaves the chute. Determine the velocity of the car/coal system after the coal has come to

    asked on October 14, 2008
  9. physics

    A primitive diving bell consists of a cylindrical tank with one end open and one end closed. The tank is lowered into a freshwater lake, open end downward. Water rises into the tank, compressing the trapped air, whose temperature remains constant during

    asked on November 19, 2008
  10. math

    a recipe calls for 2 1/2 quarts of fish stock and 1 1/2 pounds of shrimp. what is the unit rate of fish stock to shrimp in the gumbo

    asked on April 12, 2016
  11. physics

    When a water gun is fired while being held horizontally at a height of 1.14 m above ground level, the water travels a horizontal distance of 4.50 m. A child, holding the same gun in a horizontal position, slides down a 34.0◦ incline at a con- stant

    asked on January 14, 2014
  12. physics

    An airplane is flying horizontally with a constant velocity of 160 m/s at an altitude of 5400 m when it drops a package. How far ahead of the target along the x direction should the plane be when it releases the package?

    asked on February 25, 2009
  13. chemistry

    How many joules of energy would be liberated by condensing 49.6 mol of steam at 100.0 °C and allowing the liquid to cool to 30.0 °C?

    asked on November 15, 2014
  14. physics

    When you take a bath, how many kilograms of hot water (48°C) must you mix with cold water (13°C) so that the temperature of the bath is 36°C? The total mass of water (hot plus cold) is 185 kg. Ignore any heat flow between the water and its external

    asked on November 17, 2008
  15. chemistry

    find the maximum value of h2(g)in grams that would be expected to form by reacting 6.54g of zinc with 50ml of 0.1M of HCl.

    asked on July 22, 2011
  16. physics II

    the lens to retina distance in the human eye averages 2.0cm what is the power of the lens of the human eye

    asked on July 20, 2011
  17. physics

    alpha particles are accelerated through a potential of 1000volts and then enter a magnetic field 0.2T perpendicular to the their direction of motion.Calculate the radius of the circular path that they traverse.An alpha particle has a mass 6.68x 10^-27kg

    asked on April 6, 2011
  18. physics

    a supertanker with a mass of 5.0 x 10 to the 8th power kg accelerates from rest to a speed of 10 m/s in a time of 1000s. what is its average acceleration? how much force is required to accelerate the supertanker?

    asked on October 4, 2010
  19. math

    need help with "you have $15 in your bank account. you spend $11 on a hat. then you mow 3 lawns for $20 each and deposit the money into your bank account, write and solve an expression (using order of operations) to determine how much money is in your

    asked on January 5, 2012
  20. biology

    lipid soluble must be oxidized before they are excreted from.otherwise the toxins would not be able to pass through the a)bowman capsule b)red blood cells c)cell membranes d)cytoskeleton

    asked on July 22, 2011
  21. Physics

    The space between two points

    asked on February 22, 2011
  22. government

    . The source of the Supreme Court’s authority is (Points : 1) moral suasion. judicial activism. concurring opinion. dissent.

    asked on February 26, 2013
  23. biology

    (Which of the following would least likely induce thirst) a)Dry pharynx b)Decrease blood volume c)decrease blood pressure d)decreased blood osmolarity

    asked on July 22, 2011
  24. Algebra

    The first three equations I have solved, I would just appreciate someone checking them over to make sure I'm doing them right. Find the GCF: 16x^2z ,40xz^2 , 72z^3 = 3^3z Factor our GCF: a(a+1) - 3(a+1) = a+1 Factor Polynomial: 9a^2 - 64b^2 =

    asked on January 22, 2009
  25. physics

    the mass of the water is 131 kg and its initial temperature is 24.2°C, how much energy must the water transfer to its surroundings in order to freeze completely? The specific heat of water is 4186 J/kg·K, and the latent heat of fusion is 333 kJ/kg

    asked on August 5, 2014
  26. IT

    You have been tasked with the project of organizing a company offsite 2-day training session in which people are brought in from different parts of the country. This entails everything from preparation, accommodations, and facilities. • There is APA

    asked on July 17, 2013
  27. physics

    11. The charged plates of a parallel plate capacitor each have a charge density of 3 x 10-3 C/m2. What is the electric field E between the plates?

    asked on March 15, 2011
  28. geometry

    A rope is connected to a boat and to the boat's anchor that is resting on the ocean floor at a position not directly under the boat. The rope is 105 feet long and the water is 55 feet deep. To the nearest tenth of a foot, how far is the anchor from a point

    asked on October 2, 2008
  29. geometry

    A rope is connected to a boat and to the boat's anchor that is resting on the ocean floor at a position not directly under the boat. The rope is 105 feet long and the water is 55 feet deep. To the nearest tenth of a foot, how far is the anchor from a point

    asked on October 2, 2008
  30. algebra

    solve for x: 2(x-3) - 3(x+5) = 3 (x-2) - 7 Perform the indicated multiplications; add up the constants and the terms that involve x; then get all terms that involve x on one side of the equation. 2x -6 -3x -15 = 3x -6 -7 -x -21 = 3x -13 -8 = 4x x = ? -2

    asked on July 10, 2007
  31. calculus

    suppose the set of points have the following coordinates:(-2,3),(4,-4),(2,-3). please calculate the moment of this set of points about the x-axis and also about the center.

    asked on August 17, 2012
  32. chemistry

    what is the angular momentum quantum number for the orbital from which an Mg atom loses two electrons to form Mg2+ ion.

    asked on July 20, 2011
  33. algebra

    A homeowner wishes to insulate her attic with fiberglass insulation to conserve energy. The insulation comes in 40-cm wide rolls that are cut to fit between the rafters in the attic. If the roof is 6 m from peak to eave and the attic space is 2 m high at

    asked on July 4, 2007
  34. math

    i have a math question and i know that there is a simple solution that i am missing. We are going to be given a 100 foot piece of rope and we have to make a baseball diamond where the bases are 60feet apart. Help

    asked on August 31, 2009

    A molecule consists of two atoms. The atoms have masses of 17 u and 14 u and are 1.78e-10 m apart. How far from the first atom is the center of mass of the molecule?

    asked on October 14, 2008
  1. chemistry


    posted on July 11, 2019

    I have the same question but I'm not sure if we have the same answer choices... A. used to compare to cultures C and D B. used to compare to cultures A and B C. used as a control D. all of the above E. none of the above correct= D

    posted on April 23, 2017
  3. Math- Linear Equations

    suppose a new watersports company aqua sports is open for business they are running a grand opening sale their rental cost can be modeled by linear equation we are told that for 30 minutes of use their rental cost will $50 for 60 minutes of use their

    posted on December 15, 2014

    bob is correct, except that you have to subtract the Force*sin(31). It's a poorly worded problem, to say the least.

    posted on April 2, 2013
  5. Chemistry

    Oh... I see where I went wrong. thanks!

    posted on March 11, 2013
  6. Chemistry

    Ok, that's what I did before. so 2E-11 = x^2/(0.1-x) so x^2 = 2E-12 - 2E-11x But what I don't understand then is how do we solve for x? I used the quadratic equation but when I plugged in those values it gives me 0. So where am I going wrong?

    posted on March 11, 2013
  7. Chemistry


    posted on March 11, 2013
  8. Chemistry

    I'm really confused. I've never done a problem like this before. Could you plug in the values for me? It just doesn't make any sense and my teacher won't explain it to me when I ask about it.

    posted on March 11, 2013
  9. Chemistry

    But what's Kw? and the value for NH3? Is that just x? So should it be Kw/5.0x10-4 =(x)(x)/(0.1-x)

    posted on March 11, 2013
  10. Chemistry

    I'm not sure how to set up the equations using the volumes, and I'm not even sure what givens I'm supposed to use.

    posted on March 11, 2013
  11. chemistry

    If you heated a hydrate too quickly and some of it splattered out of the beaker how would it affect the calclated percent by mass of water and the molecular formula

    posted on May 11, 2010
  12. Physics

    Chris Cheggies

    posted on January 10, 2010
  13. physics

    PV=nRT ideal gas law is the only thing i got n R T will stay constant i believe so that leaves me with PV so PV of initial vs. PV of final... maybe

    posted on November 19, 2008
  14. physics

    just guessing but normal atmospheric pressure

    posted on November 19, 2008
  15. Math


    posted on October 14, 2008
  16. physics

    thank you

    posted on October 14, 2008
  17. algebra 1

    it equals a negative number

    posted on October 2, 2008