Katherine

Most popular questions and responses by Katherine
1. Chemistry

Using the following data calculate Delta Sfus and Delta Svap for K in J/mol-k Tm(K) = 336, Delta H Fus(kJ/mol) = 2.33, Tb (K) = 1033, Delta H vap (kJ/mol) = 77.1 For Delta S fus i'm supposed to use 336 K the Tm value and for Delta S vap i'm supposed to use

asked on March 9, 2012
2. SS

How is the number of Electoral College seats per state determined? (1 point) by the number of party delegates assigned to the state by the total number of House and Senate representatives by the traditional number assigned under the 12th Amendment by

asked on October 5, 2016
3. Chemistry

Under standard conditions (298 K and 1 atm), which statement is true? a] diamond converts to graphite spontaneously b] graphite converts to diamond spontaneously c] none of the above How can the spontaneity of the reaction be reversed? a] increase the

asked on March 8, 2012
4. Math

Shelly compared the number of oak trees to the number of maple trees as part of a study about hardwood trees in a woodlot. She counted 9 maple trees to every 5 oak trees. Later in the year there was a bug problem and many trees died. New trees were planted

asked on September 19, 2013
5. chemistry

Indicate the number of equivalents in each of the following: 4mol Mg2+ 0.1mol H+ 2mol Cl- 3mol Fe3+

asked on September 12, 2012
6. Chemistry

For the reaction described by the chemical equation: 3C2H2(g) -> C6H6(l) .. Delta H rxn = -633.1 kJ/mol a) Calculate the value of Delta S rxn at 25.0 C... b) Calculate Delta G rxn... c) In which direction is the reaction, as written, spontaneous at 25 C

asked on March 9, 2012
7. Chemistry

The voltage generated by the zinc concentration cell described by, Zn(s)|Zn2+ (aq, 0.100 M)||Zn2+ (aq, ____ M)|Zn(s) is 24.0 mV at 25 °C. Calculate the concentration of the Zn2 (aq) ion at the cathode. Hi, I posted this question awhile back but I think it

asked on June 7, 2012
8. Chemistry

The Ksp of CaSO4 is 4.93× 10–5. Calculate the solubility (in g/L) of CaSO4(s) in 0.300 M Na2SO4(aq) at 25 °C

asked on November 12, 2013
9. Chemistry

A 0.450-gram sample of impure CaCO3(s) is dissolved in 50.0 mL of 0.150 M HCl(aq). The equation for the reaction is: CaCO3(s)+2HCl(aq) -> CaCl2(aq) + H2O(l) + CO2(g) The excess HCl(aq) is titrated by 9.75 mL of 0.125 M NaOH(aq). Calculate the mass

asked on April 10, 2012
10. Chemistry

Calculate the concentrations of all species in a 0.810 M Na2SO3 (sodium sulfite) solution. The ionization constants for sulfurous acid are Ka1 = 1.4 x 10^-2 and Ka2 = 6.3 x 10^-8 so I'm trying to find Na, SO3 2-, HSO3-, H2SO3, OH-, H+ and heres what I

asked on April 20, 2012
11. Physics

A 4-kg sled sliding freely on an icy surface experiences a 2 _ N frictional force exerted by the ice and an air-resistive force of 0.5 N. a. What is the net force acting on the sled? b. What is the acceleration of the sled?

asked on December 28, 2010
12. English

Why does Yoni think the Arab he finds is perfect for his film? It was in Bethlehem, actually, that Yonatan found his Arab, a handsome man who used his first wish for peace. His name was Munir; he was fat with a big white mustache. Superphotogenic. It was

asked on September 9, 2017
13. Chemistry

A solution household bleach contains 5.25% NaClO, by mass. Assuming that the density of bleach is the same as water(1.0g/ml). Calculate the volume in mL of household bleach that should be diluted with water to make 500.0 ml of a pH= 9.80 solution. Here's

asked on April 20, 2012
14. Chemistry

Consider two cells, the first with Al and Ag electrodes, and the second with Zn and Ni electrodes, each in appropriate 1.00M solutions of their ions. If 2.10g of metal is plated in the voltaic cell, how much metal is plated in the electrolytic cell?

asked on June 3, 2012
15. Chemistry

A generic solid, X, has a molar mass of 77.7 g/mol. In a constant-pressure calorimeter, 31.2 g of X is dissolved in 289 g of water at 23.00 °C. The temperature of the resulting solution rises to 24.40 °C. Assume the solution has the same specific heat as

asked on November 2, 2014
16. Chemistry

Silver chromate is sparingly soluble in aqueous solutions. The Ksp of Ag2CrO4 is 1.12× 10–12. What is the solubility (in mol/L) of silver chromate in 1.4 M potassium chromate aqueous solution? In 1.4 M silver nitrate aqueous solution? In pure water?

asked on November 12, 2013
17. Chemistry

Calculate delta G of the reaction at 25 degrees C: 2Au^3+ (aq) + 3Ni(s) 2Au(s) + 3Ni^2+(aq) Au3+ + 3e- ==> Au Eo = +1.50V Ni2+ + 2e- ==> Ni Eo = -0.23 V 2Au3+ + 3Ni ==> 3Ni2+ + 2Au The answer is -1.00 x 10^3 kJ but i'm not getting that answer!!!!!!! please

asked on June 3, 2012
18. Chemistry

Assume equal concentrations, rank these solutions by pH HBrO, Ca(OH)2, HCl, KOH, NH3 Here's how I ranked it: highest: Ca(OH)2 > HCl > KOH > NH3 > HBrO lowest is this correct? if not please tell me why!

asked on April 16, 2012
19. chemistry

In the following experiment, a coffee-cup calorimeter containing 100 mL of H2O is used. The initial temperature of the calorimeter is 23 degrees Celsius. If 4.00 g of CaCl2 is added to the calorimeter, what will be the final temperature of the solution in

asked on October 19, 2009
20. Chemistry

What NaCl concentration results when 209 mL of an 0.660 M NaCl solution is mixed with 492 mL of a 0.270 M NaCl solution? __ mol/.209 L = 0.660 M __ mol/.492 L = 0.270 M .. I have no idea how to solve this. I have no idea why I even set up the equation

asked on April 9, 2012
21. math

a true or false test has 5 questions. what is the probability of guessing exactly four out of the five answers correstly.

asked on November 6, 2009
22. Chemistry

A current of 5.18 A is pass through a Cr(NO3)2 solution for 1.20 hours. How much chromium is plated out of the solution? __g I have no idea how to approach this. Here's what I tried to do logically but I'm not sure if it works out: I know that the

asked on June 3, 2012
23. chemistry

Calculate the cell potential for the following reaction as written at 51 degrees C, given that [Zn2+] = 0.837 M and [Sn2+] = 0.0180 M. Zn(s) + Sn^2+(aq) = Zn^2+(aq)+Sn(s) E = __ V Reduction Half-Reaction Standard Potential Ered° (V) Zn2+(aq) + 2e– →

asked on June 7, 2012
24. math

A number N is multiplied by 3. The result is the same as when N is divided by 3. What is the value of N?

asked on April 30, 2019
25. Chemistry

What mass of precipitate will form if 1.50L of concentrated Pb(ClO3)2 is mixed with 0.200L of 0.280M of NaI? Assume the reaction is complete

asked on April 17, 2013
26. Chemistry

Phosphorus pentachloride decomposes according to the chemical equation PCl5(g) -----> PCl3 (g)+ Cl2(g) Kc= 1.80 at 250 degrees C A 0.206 mol sample of PCl5(g) is injected into an empty 3.30 L reaction vessel held at 250 °C. Calculate the concentrations of

asked on September 30, 2013
27. Chemistry

A reaction: A(aq) + B(aq) C(aq) has a standard free-energy change of –4.65 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?

asked on November 24, 2013
28. Physics

Show that the average speed of a rabbit that runs a distance of 30 m in a time of 2 s is 15 m/s. I have a whole bunch of problems such as these and i'm not sure what math formula to use to figure problem.I know its Acceleration ! change of velocity time

asked on October 10, 2012
29. Chemistry

At 25 degrees Celsius all of these are true for a neutral solution : pH = 7.00, pOH = 7.00, and [H+] = [OH-] is that correct? For a neutral, aqueous solution regardless of temperature.. would the only correct statement be [H+] = [OH-]? pH = 7.00 and pOH =

asked on April 16, 2012
30. Chemistry

I'm a bit iffy on oxidation numbers... can someone please tell me if this is correct? Assign oxidation states to each element on both sides of the equation : KClO2--->KCl+O2 Reactants K = +1 Cl = +1 O = -2 Products K = +1 Cl = -1 O = 0 the element being

asked on May 20, 2012
31. Language Arts

Which of the following sentences contains a dependent clause? a) my mother, who never wastes anything, rinsed and saved the take-out boxes b) we were running late and, we had to skip stopping by the post office. c) I had never been to New York before this

asked on March 10, 2016
32. US History

The question is "How might Juan Cabrillo's explorations affect later settlements in CA?" In the book there's only a little sentence talking about him.. "Cabrillo sailed 1,200 miles along the coast of what is now California. Cabrillo failed to find wealth,

asked on October 6, 2010
33. SS

Which factors led to the downfall of Ghana? Select all that apply. A. Ghana was engaged in conflict with people to the north. B. Ghana lacked nearby water resources. ******* C. Ghana was unwilling to participate in trade. D. Ghana's large population began

asked on April 1, 2019
34. math

an empty rectangle tank with a base area of 2400 cm^2 is filed with water from 2 taps. one tap can fill the tank with 12L of water per minute, while the other tap can do it at 3l less perminute. (A) what will be the depth of water in the tank after both

asked on November 30, 2010
35. Math

Tiffany bought 2/5 kg of cherries. Linda bought 1/10 kg of cherries less than Tiffany. How many kg of cherries did they buy altogether?

asked on January 22, 2014
36. Chemistry

I keep getting the last part of this question wrong. Strong base is dissolved in 765 mL of 0.200 M weak acid (Ka = 4.63 x 10^-5) to make a buffer with a pH of 4.18. Assume that the volume remains constant when the base is added. HA(aq) + OH-(aq) -. H2O(l)

asked on May 13, 2012
37. Physics

Take two Styrofoam cups, partially fill them with equal amounts of cold water, and drop equal amounts of ice into each cup to obtain a mixture of ice and water. a. Stir the water and ice mixture in one of the cups vigorously with a nonmetallic stirrer

asked on December 28, 2010
38. Chemistry

Delta H is 20.1 kJ/mol and Delta S is 45.9 J/(mol-k). Assuming these values change very little with temperature, over what temperature range is the reaction spontaneous in the forward direction? Is the reaction spontaneous for temperatures less than or

asked on March 9, 2012
39. AP Stats

Bolivian adult females are much shorter than US females although the standard deviation of their heights is about the same at 2.3 inches. Only 4.1% of Bolivian females are at least five feet tall. What is the mean height of adult Bolivian women assuming

asked on September 25, 2017
40. Chemistry

Calculate the final concentration for the standardization of KMnO4 given this information: 2MnO4- + 5C2O4^-2 + 16H+ -> 2Mn^2+ + 10CO2 + 8H2O [final redox equation] Volume of KMnO4 titrated with H2SO4 + Na2C2O4 = 293 mL Volume KMnO4 titrated with H2SO4

asked on May 2, 2012

Luisa and Connor had $360 altogether. After Connor gave Luisa 2/5 oh his money, she had the same amount of money as he did. How much money did Connor have in the beginning? asked on April 12, 2011 42. Math A company paid$110,000 for a new 18-wheeler. When it is 9 years old it will be worth $20,000. Using straight-line depreciation, the value of the trick in dollars, V, is a linear function of its age in years, n. Find the function and the value when the asked on August 22, 2018 43. Math In Wilbur's math class, his grade is based on the average score of six tests, each worth 100 points. Wilbur always worries about his grade. He knows that his average on the four first tests is 88.5. What is the lowest average he could get on his next two asked on September 22, 2010 44. Math Statistics "In the United Kingdom's Lotto game, a player picks six numbers from 1 to 49 fir each ticket. Rosemary brought one ticket for herself and one for each of her four adult children. She had the lottery ticket. When the sic winning numbers were drawn, Rosemary asked on February 7, 2017 45. Chemistry There is a current being applied to an aqueous solution fo sodium bromide. What is produced at the cathode and anode? I said that Na(s) being produced at the cathode and Br2(l) being produced at the anode. The other options are H2 and O2 for either but asked on May 20, 2012 46. Language Arts What is the pattern of stressed and unstressed syllables in this line: The sun should drop its greatest gold asked on March 2, 2016 47. math Daniel gave 4/5 of his stickers to Javier. Javier’s collection of stickers increased to 64. If Javier had 28 stickers in the beginning, how many stickers did Daniel have in the beinging? can u please show the work and explain how u got it...so i could asked on March 31, 2011 48. Chemistry 60cm3 of hydrogen diffused through a porous membrane in 10minutes.The same volume of gas G diffused through the same membrane in 37.4 minutes .Determine the relative molecular mass of G.(H=1) asked on January 4, 2019 49. math A store sells two types of nut mixtures. The standard mix contains 100 grams of cashews and 200 grams of peanuts and sells for$2. The deluxe mix contains 120 grams of cashews and 40 grams of peanuts and sells for $2.50. The store has 15kilograms of asked on April 20, 2018 50. chemistry The Rydberg equation (1/lambda=R/ni^2–R/nf^2) can be treated as a line equation. What is the value of nf as a function of the slope (m) and y-intercept(b)? asked on January 10, 2010 51. College Chem. If 20.0 mL of glacial acetic acid (pure HC2H3O2) is diluted to 1.30 L with water, what is the pH of the resulting solution? The density of glacial acetic acid is 1.05 g/mL. asked on March 8, 2010 52. math Hitomi has a total of 30 red and blue bowling balls at her bowling alley. Each red ball weighs 8 lb. Each blue ball weighs 9 lb. If the total mass of the blue balls is 49 lb. heavier than the total mass of the red balls, how many red balls does she have? asked on March 3, 2011 53. Chemistry Calculate the concentrations of all species in a 0.810 M Na2SO3 (sodium sulfite) solution. The ionization constants for sulfurous acid are Ka1 = 1.4 x 10^-2 and Ka2 = 6.3 x 10^-8 I calculated SO32- = 0.8096 M, HSO3- = 3.58E-4, H2SO3 = 7.1E-13, OH- = asked on April 21, 2012 54. Chemistry How much solid ammonium chloride would be needed to make 100 mL of a 0.5M solution? asked on May 18, 2016 55. Chem 11 So I did a lab determining the chemical formula of a hydrate. I really just need somebody to check this over for me. We had to find the molecular formula of a hydrate of copper (2) sulphate, CuSO4 .xH2O. My observation table looks like this: Mass of clean, asked on November 18, 2014 56. Need Help with Math? 1. Translate P(4,0) right 3 units and up 5 units. Give the coordinates of the image point. (-5,1) (1,-5) (5,7) (7,5) 2. Point A(6, -2) is reflected over the x-axis. Write the coordinates of A'. 6,2 6,-2 -6,2 -6,-2 asked on October 11, 2013 57. History Hi, I need help finding a news article about 9/11. It has to be about 8 pages or longer. any links to any news?? Thank you! asked on May 16, 2019 58. math !!!! :O Amanda is 12 years old. She is 2/7 times as old as her father. How many years ago was her father 4 times as old as Amanda. asked on March 21, 2011 59. math kyle had 36 books in hislocker. some were library books, some were textbooks, and the rest were telophone books. the number of library books and textbooks combined equal twice the number of textbooks. the number of textbooks and telephone books combined asked on November 10, 2010 60. Chemistry The kinetic energy of a rolling billiard ball is given by {\rm{KE}} = 1/2\,mv^2 . Suppose a 0.17-{\rm kg} billiard ball is rolling down a pool table with an initial speed of 4.5 m/s. As it travels, it loses some of its energy as heat. The ball slows down asked on October 9, 2009 61. Chemistry C6H5COOH(aq) + NO2-(aq) C6H5COO-(aq) + HNO2(aq) A table of ionizations is given to calculate the equilibrium constant for this overall reaction.. but when i looked onto the table the only thing given was the Ka for C6H5COOH [6.3×10^–5] and HNO2 asked on April 20, 2012 62. Chemistry When 1 mol of a gas burns at constant pressure, it produces 2424 J of heat and does 6 kJ of work. How do i calculate delta E for this problem? I tried q+w but that didn't work for me. I got the answer wrong. asked on October 9, 2009 63. Chemistry There are several technological applications for the transuranium elements (Z > 92). An important one is in smoke detectors, which can use the decay of a tiny amount of americium-241 to neptunium-237. What subatomic particle is emitted from that decay asked on July 23, 2019 64. Chemistry What is the significance of the distance between two metals in the activity series? asked on March 4, 2013 65. math !!!! :O The ratio of the number of postcards john had to the number of postcards Zachary ha d was 4:9. Zachary had 45 more postcards than John. After giving some postcards to John, Zachary had 6/7 as many postcards as John. (A) How many postcards did Zachary have asked on April 4, 2011 66. Chemistry Can someone help me with this problem.... i have an exam coming tomorrow and im doing practice problems but i dont know how to do this Calculate the specific heat of a metal if 2.36102 grams of it at 99.5 degrees celsius is added to 125.0 mL of water at asked on May 20, 2019 67. math !!!! :O Tierra, Nico, and Alex had$865 altogether. Tierra spent 2/5 of her money. Nico spent $40 , and Alex spent twice as much as Tierra. If the three friends had the same amount of money left, how much money did Alex have in the beginning. asked on February 24, 2011 68. Physics The electric field at the point x=5.00 cm and y=0 points in the positive x direction with a magnitude of 10.0 N/C. At the point x=10.0 cm and y=0, the electric field points in the positive x direction with a magnitude of 15.0 N/C. Assuming the field is asked on February 7, 2010 69. Chemistry 11 So I did a lab determining the chemical formula of a hydrate. We had to find the molecular formula of a hydrate of copper (2) sulphate, CuSO4 .xH2O. My observation table looks like this: Mass of clean, dry test tube: 21.6g Mass of test tube + hydrated asked on November 18, 2014 70. objective and eyepiece lens What is the approximate magnification of a compound microscope with objective and eyepiece focal lengths of 0.3 cm and 3.6 cm, respectively, and a separation between lenses of 20 cm? The answer is 460. I tried finding the magnification for the eyepiece asked on May 22, 2009 71. Chemistry 105 The molar heat capacity of silver is 25.35 J/mol*C. How much energy would it take to raise the temperature of 12.0 g of silver by 14.6 degrees Celsius? asked on April 2, 2011 72. Physics A car is backing up at a rate of 10km/hr. If the driver looks through his rear-view mirror, how fast does a tree, which is behind him, appear to approach him? asked on October 27, 2016 73. chemistry 1.which of the following is the most polar bond? explain n-f c-f h-f o-f 2. in the trigonal bipyramidal geometry, which position - axial or equatorial - do nonbonding electrons prefer? why? 3.under what circumstances is the molecular geometry around a asked on April 23, 2010 74. science why are plastic handles on frying pans safer to than metal handles asked on May 22, 2012 75. Chemistry Calculate the equilibrium constant for the following reaction at 100°C. 2 TiCl3(g)+2 HCl (g) = 2 TiCl4(g)+H2(g) ∆G°rxn = + 47.0 kJ mol-1 cant i just use K = e^ -Delta G/RT? --> K = e ^ -47.0 kJ mol-1 /(8.314)(273+100)? what is the point of having the asked on March 15, 2012 76. Algebra True or false? Negative numbers are closed under addition. Give a counterexample True or false? Prime numbers are closed under subtraction. Give a counterexample True or false? Natural numbers are closed under division. Give a counterexample asked on August 15, 2016 77. math a is the set of siamese cats b is the set of cats how do I determine whether the pairs of sets are equal, equivalent, both or neither? asked on August 11, 2010 78. math jake spent 3/8 of his money on a book and 1/2 of what was left on a magazine.he now has$6.25. how much money did he start with? please help me i am confused... thank you :)

asked on April 20, 2010
79. sewing2

Mrs. Shotto was once one of your regular customers, but she hasn't asked to have any garments made in approximately one year. You note she has lost weight. She would like you to make her a special silk blouse to replace a favorite blouse that has worn out.

asked on April 20, 2010
80. algebra

an orange has 20 fewer calories than a banana. If 7 bananas have the same number of calories as 9 oranges, how many calories are in a banana?

asked on September 29, 2008
81. Math

I am not sure how to answer this can someone please explain it to me: Find a polynomial with integer coefficients that satisfies the given conditions. P has a degree 2, and zeros 1+i and 1-i Thank You!

asked on October 10, 2019
82. physics

Displacement vectors A,B,and C add up to a total of zero. Vector A has a magnitude of 1550 m and a direction of 24.1° north of east. Vector B has a direction of 41.0° east of south, and vector C has a direction of 33.4° north of west. Find the

asked on October 30, 2014
83. Accounting

How do I calculate the future value of the following? $5,000 compounded annually at 12% for 2 years$5,000 compounded semiannually at 12% for 2 years $5,000 compounded quarterly at 12% for 2 years$5,000 compounded monthly at 12% for 2 years

asked on November 16, 2010
84. math

a student playing a computer chess game gets 5 points every time he wins a round.the computer gets 3 points every time it wins a round.they play 64 rounds and end with a tied score.how many rounds did the computer win. please help me .. i think the answer

asked on April 22, 2010
85. Chemistry

how much silver nitrate must be measured to yield 1.00g silver?

asked on October 18, 2009
86. math

What is the base 7 representation of the number 275? 21201 is the base 3 representation of what number? I'm having trouble with both questions. Can someone help me out? I tried using the internet but I was still confused.

asked on January 31, 2018
87. physics

What is the acceleration of a car going from 3.0 x 101 km/hr to 1.20 x 102 km/hr in 3.0 x 101 sec?

asked on October 3, 2014
88. math

container A has twice the capicity of container B. container A is full of sand and container B is empty. suppose 1/8 of the sand in container A is poured into container B. what fractional part of container B will conatin sand.........please halpme i am

asked on March 22, 2010
89. Chem

The hydrolysis of sucrose into glucose and fructose in acidic water has a rate constant of at 25 degrees C. Assuming the reaction is first order in sucrose, determine the mass of sucrose that is hydrolyzed when 2.60 L of a 0.150 M sucrose solution is

asked on February 28, 2010
90. Language Arts

Which of the following sentences contains a dependent clause? a) my mother, who never wastes anything, rinsed and saved the take-out boxes b) we were running late and, we had to skip stopping by the post office. c) I had never been to New York before this

asked on March 10, 2016

Kaylee got a 15% raise. She now earns $23 an hour. How much did she earn before the raise? asked on April 12, 2014 92. social studies How are petitions and Demonstrations similar? asked on February 18, 2013 93. science How many seconds does it take for mercury to go from 0 degrees celsius to 300 degrees celsius? asked on January 29, 2013 94. Chemistry The voltage generated by the zinc concentration cell described by, Zn(s)|Zn2+ (aq, 0.100 M)||Zn2+ (aq, ____ M)|Zn(s) is 24.0 mV at 25 °C. Calculate the concentration of the Zn2 (aq) ion at the cathode. My textbook advised me to use the Nernst Equation and asked on June 3, 2012 95. Chemistry Hydrazine, N2H4 can be made (on paper) by reaction of molecular nitrogen and molecular hydrogen, 2 H 2 ( g ) + N 2 ( g ) --> N 2 H 4 ( g ) and suppose that the equilibrium constant Kp has the value 1×10^–3. (a) A stoicheometric mixture of H2 and N2 is asked on August 13, 2011 96. math each face of a cube can be painted either red or yellow. how many differents ways can you paint the cube? i thinks its 18 ways i don't know please help me asked on April 22, 2010 97. Math 1. A total of$10,000 is to be divided between Sean and Georg, with George to receive \$3000 less than Sean. How much will each receive? pls help

asked on January 26, 2010
98. physics

What is the longest wavelength that can be heard by a normal ear?

asked on April 22, 2012
99. physics

A block is projected up a frictionless inclined plane with initial speed v0 = 8.42 m/s. The angle of incline is è = 58.4°. (a) How far up the plane does it go? (b) How long does it take to get there? (c) What is its speed when it gets back to the bottom?

asked on October 9, 2010
100. chemistry

The thermal decomposition of calcium carbonate produces 2 by-products, c02 and calcium oxide. calculate the volume of the co2 produced at STP from the decomposition of 231 grams of caco3. i know the equation i need to use is V=nrt/p but am i supposed to

asked on February 18, 2010

1. 1
2. 2
3. 3
4. 4
5. 5