# Katherine

Popular questions and responses by Katherine
1. ## 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

2. ## chemistry

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

3. ## 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

4. ## 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

5. ## 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

6. ## 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

7. ## 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

8. ## 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

9. ## Calculus 1

A 16 foot ladder is leaning against a wall. If the top slips down the wall at a rate of 4 ft/s, how fast will the foot be moving away from the wall when the top is 15 feet above the ground?

10. ## 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

11. ## 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 =

12. ## 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

13. ## 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

14. ## 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

15. ## 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?

16. ## 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?

17. ## 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?

18. ## 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?

19. ## 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.

20. ## 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!

21. ## 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

22. ## 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

23. ## 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

24. ## Math

which of the following best completed the sequence C3, H8, M13, R18

25. ## 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

26. ## math

Andy had 20% fewer marbles than Henry. When Andy gave 80 marbles to Henry, the number of marbles he had left was half of what Henry had. How many marbles did Andy have in the beginning? please help me

27. ## 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

28. ## 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

29. ## Physics

A man driving a car toward a large vertical wal sounds his horn. The car is traveling at 81 km/h. The echo off the wall is heard by the man at a frequency of 958 Hz. What is the frequency of the car's horn?

30. ## 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

31. ## 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

32. ## 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

33. ## math

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

34. ## 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,

35. ## 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

36. ## Algebra 1

1. A company is deciding whether or not to hire a new worker. The company must pay the worker hourly and cover a daily cost for insurance. The cost to pay an hourly worker for one day is represented by the function y = 8x + 25, where x is hours. What is

37. ## 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?

38. ## physics

A diver springs upward from a board that is 2.98 meters above the water. At the instant she contacts the water her speed is 9.39 m/s and her body makes an angle of 70.4° with respect to the horizontal surface of the water. Determine her initial velocity.

39. ## math !!!! :O

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?

40. ## 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

41. ## 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

42. ## chemistry (need by 5!!)

use the van der waals equation to calculate the pressure of 4.00 mol of H20 at 471K in a 4.60-L vessel. how do you solve?

43. ## 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?

44. ## math

Lily went for 8 rides at the county fair. Some rides were on the merry-go-round, and the rest were on the pirate ship. The total cost of all rides was \$6.30. Each pirate ship ride cost \$0.60, and each merry-go-round cost \$0.90. How many pirate ship did

45. ## Algebra II

Choose the correct rewriting of this algebraic fraction and give the exclusion represented by your choice. 4y(8y+24)^ - 1 : 2y/2y+3 OR y/(2)(y+3)? y ≠ : +3 OR -3 ?

46. ## Literature

I am doing a collage about Fahrenheit 451 and basically we have to make a collage with chunks of writing about quotes that relates back to our proposal. Would It be okay if someone looked at it? Proposal: I am interested in how the government doesn’t

47. ## 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

48. ## HEALTH

The heart is a _____ that provides the force necessary to circulate the blood to all the tissues in the body. A. Skeletal pump B. Autonomous pump C. Muscular pump D. Systemic pump My answer would be C. i think that's right...

49. ## history

During the 1950s, the advent of _______ created the largest and fastest-growing impact on American society. A. television. B. suburban communities C. educational reform D. fundamentalist religion. I think it's D. Am I correct?

50. ## 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?

51. ## 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

52. ## 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

53. ## 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

54. ## 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.

55. ## 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,

56. ## algebra

If Sam Stevens and four other friends want to schedule a 6 hour fishing trip on Lake Ontario with Reel Easy Sport Fishing. The cost for five people is \$445. The cost for six people is 510. How much money per person will Sam and each of his friends save if

57. ## math

an alphabet book will have one letter on each page. eight pages will be printed on a single piece of paper.you fold the paper in half.then you fold it in half again and trim the edges. the eight pages appear in order. draw the layout for two sides of the

58. ## 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

59. ## 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

60. ## math

a worker in a city park needs to cover a circular path around the outside of a flower garden with gravel. the radius of the garden is 15 feet and the path surrounding the garden is 6 feet wide. how many square feet need to be covered with gravel? explain

61. ## science

what are three ways to make a sugar cube dissolve more quickly in water

62. ## math

Tom,Ted,Tony,Terry worked together on a job.The job paid \$500.Each boy was paid according to the amount of work he contributed to the job.Ted and Tony earned \$280 together.Ted and Tom have \$260,and Ted and Terry got \$220.What percent of the job did each

63. ## math

your aunt is building a garden in her backyard.she has 90ft of fencing to surroud it.if she wants the lenght to be 15 ft onger than the width , what should the dimensions of her garden be

64. ## Chemistry

Given the following equations: 2 H2 (g) + O2 (g)--> 2 H2O (l) deltaH = -571.6 kJ N2 (g) + O2 (g)-->2 NO (g) deltaH = +180.5 kJ N2 (g) + 3 H2 (g) --->2 NH3 (g) deltaH = -92.22 kJ Determine the enthalpy change (deltaH) for the following reaction: 2 NO (g) +

65. ## science

speculate about how pollution of the ecotone might affect the surrounding ecozones.

66. ## 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!

67. ## 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

68. ## 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)

69. ## Physics

So tomorrow I have a presentation about the universal law of gravitation and my partner did not work! At all! I'm really upset right now and I'm having trouble with understanding about the orbit of the moon. The slide has to be short and simple and I dont

70. ## 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.

71. ## Literature

Self-Interview "I have always understood that's why I have been so frequently called 'a revolutionist.' It sounds as I have done some crime! Well, it may be the American black man does need to become involved in a real revolution. The word for "

72. ## history

I have an essay about symbolic occupation, but first I am suppose to know how did religion shape symbolic occupation but the text we have is very complicated to understand.

73. ## Chemistry

How much solid ammonium chloride would be needed to make 100 mL of a 0.5M solution?

74. ## chemistry

How many grams of lithium hydroxide are needed to remove 920 g of carbon dioxide in the air

75. ## physics

The distance between a hydrogen atom (m = 1.0u) and a chloride atom (m = 35.5u) in the HCl molecule is 1.27×10-10m. How far from the hydrogen atom is the center of mass of the molecule?

76. ## 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?

77. ## 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

78. ## psychology

25. Teenage mothers who are accustomed to existing on hamburgers, French fries, and Cokes need to consider the nutritional needs of the child. Research has shown that a poor diet can _______________. A. restrict the development of eye and hair color B.

79. ## Chemistry

Suppose we have a solution of lead nitrate, Pb(NO3). A solution of NaCl(aq) is added slowly until no further precipitation occurs. The precipitate is collected by filtration, dried and weighed. A total of 10.27g of PbCl2(s) is obtained from 200.0mL of the

80. ## 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

81. ## science

How many seconds does it take for mercury to go from 0 degrees celsius to 300 degrees celsius?

11/12-1/9=

84. ## geometry

I need help on this question...please help. "The measures of two supplementary angles are 3x-12 and 4x-18.Find the measures of the angles.

85. ## 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

86. ## Chemistry

If a buffer solution is 0.190 M in a weak acid (Ka = 5.8 x 10^-5) and 0.550 M in its conjugate base, what is the pH? What if it said "if a buffer solution is ___ M in a weak base (Kb = ____) and ___ M in its conjugate acid, what is the pH? Would the steps

87. ## Chemistry

If a chlorine atom is lost from 1,2-dichloroethene [C2H2Cl2], would it have a higher or lower dipole?

88. ## Chemistry

I'm having a problem with a simple conversion question! "What is the molarity of 30.0 g of NH3 in 70.0 g of water? The desnity of the solution is 0.982 g/mL, and the molecular weight of ammonia is 17.0 g/mol" 1.76 mol NH3 Vsolution = mass/density V=

89. ## OChem

Confused! Please help!! Assume an organic compound has a partition coefficient between water and diethyl ether equal to 6.63. If there are initially 9.05 grams of the compound dissolved in 80.0 mL of water, how many grams will remain in the aqueous layer

90. ## social studies

if forced to choose, would you rather be a serf or a slave? defend your answer

91. ## math

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

92. ## 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???

93. ## 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

94. ## math

a student said that all squares are rectangles, but not all squares are rhombuses.What was the error??

95. ## math

Mr. Jackson is preparing bags of treats to give trick or treaters on Halloween. He has 48 pieces of candy and 60 pieces of gum. he uses all the candy and gum, and he puts the same ratio of candy to gum in each bag. What is the largest number of bags he

96. ## 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

97. ## 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

98. ## physics

You push an 37.4-kg box up an incline with an angle of 25 degrees to the horizontal with a force of 230-N. 1. What is the component of the crate's weight parallel to the surface? 2. What is the sum of the forces parallel to the surface? 3. What is the

99. ## physics

You push an 20-kg crate up an inclin with an angle of 35 degrees to the horizontal with a force of 260-N. If the crate is moving at a constant velocity: 1. what is the component of the crate's weight parallel to the surface? 2. WHat is the sum of the