# Questions Asked onFebruary 15, 2009

1. ## chem

Arsenic acid (H3AsO4) is a triprotic acid with Ka1 = 5 10-3, Ka2 = 8 10-8, and Ka3 = 6 10-10. Calculate [H+], [OH -], [H3AsO4], [H2AsO4-], [HAsO42-], and [AsO43-] in a 0.20 M arsenic acid solution. i cant do this. i don't even know how to start.

2. ## Chemistry

Calculate the concentrations of all species present in a 0.33 M solution of ethylammonium chloride (C2H5NH3Cl). Okay so i tried doing HA = H + A ice table regular it doesnt work idk what Ka to use. b/c of the chloride. i have to find [C2H5NH2][H+][OH

3. ## Physics

Light that is polarized along the vertical direction is incident on a sheet of polarizing material. Only 94% of the intensity of the light passes through the sheet and strikes a second sheet of polarizing material. No light passes through the second sheet.

4. ## Physics

please check these answers for me When an object is moving with uniform circular motion, the centripetal acceleration of the object a. is circular b. is perpendicular to the plane of motion c. is zero d. is directed toward the center of motion D What is

5. ## Chemistry

At 25°C, K = 0.090 for the following reaction:H2O(g) + Cl2O(g) 2 HOCl(g) Calculate the concentrations of all species at equilibrium for each of the following cases. (a) 1.2 g H2O and 1.6 g Cl2O are mixed in a 1.4 L flask. (b) 1.2 mol pure HOCl is placed

6. ## Physics

calculate the following, expressing the answer in scientific notation with the correct number of significan figures: (8.86 + 1.0 * 10^-3) / 3.610 *10^-3 2454.57?

7. ## chemistry

Potassium nitrate has a lattice energy of -163.8 kcal/mol and a heat of hydration of -155.5 kcal/mol. How much potassium nitrate has to dissolve in water to absorb 114 kj of heat?

8. ## Chemistry

A sample of conc. nitric acid has a density of 1.41g/ml and contains 70% HNO3 by mass. What mass of HNO3 is present per L of solution? What is the molarity?

9. ## Micro Economics

Resources are being used efficiently when 1. scarcity is not longer an issue 2. they are also used equitably 3. every opportunity to make people better off has been utilized 4. there are still gains from trade available

10. ## College: Chemistry

Hi there, I need help on my homework for chemistry and I do not understand the step on how to work this problem out. Please help me with this problem: On a Sunday morning while having your breakfast you determine that you need about 2.95X10^(5)J to heat

11. ## chemistry

Use Henry's law to determine the molar solubility of helium at a pressure of 1.5 atm and 25 degrees celsius . this is what I know... Sgas = kH x Pgas so then I plugged in... Sgas = 3.7 x 10-4 x 1.5 my answer was .055 and it is wrong. could someone please

12. ## Chemistry

NEWW- 0.10 M methylamine (CH3NH2) kb= 4.38e-4 calc the percent ionization so i did the ICE table to find that x=6.62e-3 (that was a typo the first time) and then i divided by .1 and then multiplied by 100. but i got the wrong answer whats did i do wrong?

13. ## Chemistry

When 50.0mL of 0.100M NH3 (Kb=1.8x10^-5) solution is mixed with 20.0mL of of 0.250M HCl solution, what is the pH after reaction? I solved the ka=5.56x10^-10 and I solved the moles of each nHCl and nNH3 and both have 0.005 moles. What do I do after this?

14. ## chem plzzz help

okay so im doing pre lab questions on reaction rates I have a chart labeled effects of varying concentration in reaction #1 flask A contains 7.50mL of .200 M KI , none of .20M KCI, 5.00 mL of .0050 M S2O3^2-, 1 drop of starch. Flask B contains 7.5mL of

15. ## Statistics

1) A Motor Company has purchased steel parts from a supplier for several years and has found that 10% of the parts must be returned because they are defective. An order of 25 parts is received. What are the mean and standard deviation of the defective

16. ## college: Chemistry

I need help on this homework problem and I do not understand how to work on it. Please help me with this problem. The photoelectric work function of a metal is the minimum energy needed to eject an electron by irradiating the metal with light. For calcium,

17. ## Chemistry

When 50.0mL of 0.100M NH3 (Kb=1.8x10^-5) solution is mixed with 20.0mL of of 0.250M HCl solution, what is the pH after reaction? I solved the ka=5.56x10^-10 and I solved the moles of each nHCl and nNH3 and both have 0.005 moles. What do I do after this?

18. ## Chemistry

i need help. Calculate the pH of a 0.24 M CoCl3 solution. The Ka value for Co(H2O)63+ is 1.0 10-5. how do u do these with like the Cl there?

19. ## physics

how do i do this A force of 230 N applied on a hydraulic lift raises an automobile weighing 6500 N. If the applied force is exerted on a 7.0 m^2 piston, what is the area of the piston beneath the automobile? a. 2.0 * 10^2 m^2 b. 4.0 m^2 c. 0.25 m^2 d.

20. ## Chemistry

Aluminum cookware is reffered ti as "anodized aluminum". The anodizing process puts a layer of aluminum oxide on the aluminum, protecting it from corrosion. Consider the reaction of 10.00 grams of aluminum with 10.00 grams of oxygen to form aluminum oxide.

21. ## Spanish

¿Qué piensas? 1. ¿A ti te gusta pasar un rato con los amigos? Sí, me gusta pasar un rato con los amigos. 2. ¿Qué te gusta hacer en el día de activadades con amigos? Me gusta alquilar un DVD. 3. ¿Qué otras actividades te gustan? Tambien me gusta

22. ## college-- chemistry

I am having a problem with this problem from my homework. I need some help on this problem. Microwave ovens work by irradiating food with microwave radiation, which is absorbed and converted into heat. Assume radiation with wavelength=15.0cm is used and

23. ## Physics

i'm really lost here. please show me how to solve this A 0.10 kg piece of copper at an initial temperature of 94 degrees C is dropped into 0.20 kg of water contained in a 0.28 kg aluminum calorimeter. The water and calorimeter are initially at 15 degrees

24. ## geometry

graph the following 2 graphs - y=2x+3 and y=2x-4. a)state the intersections on the y axis and the x axis. b)what is the vertical and horizontal difference between the two graphs? PLEASE help i don't understand? I know how to graph the eqautions but not too

25. ## physics

please tell me if these are correct A track star in the long jump goes into the jump at 12 m/s and launches herself at 20.0 deg above the horizontal. What is the magnitude of her horizontal displacement? (Assume no air resistance and that Ay= -g = -9.81

26. ## Writing

I'm writing a story about a girl who loves a boy that barely notices her and her best friend is trying to set them up even though he is in love with her as well. I don't know if i should make the girl fall in love with her crush or her best friend....it's

27. ## year 8 Geography

In Geography i am learning about the River Tees.for my homework i need to do a project. The questions i need to answer are:- Q 1 ) How does the river tees effect the landscape on it`s journey from the source to the mouth? Q 2 )What process takes place in a

28. ## history

How and why did Europeans perceive the peoples and resources of the New World? How and why did Native Americans perceive the peoples and resources of the Old World?

29. ## AP Chem

A 0.23 M sodium chlorobenzoate (NaC7H4ClO2) solution has a pH of 8.68. Calculate the pH of a 0.23 M chlorobenzoic acid (HC7H4ClO2) solution

30. ## Quick Spanish

1. ¿Cómo es Felipe? 2. ¿Son los chicos buenos amigos? ¿Por qué? 3. ¿Cómo son los amigos de tu clase? Please help me translate these questions. Muchas Gracias.

31. ## physics

I'm confused as how to find the current for a circuit with both parallel and series resistors? R1 = 2 Ù R2 = 5 Ù R3 = 11 Ù R4 = 10 Ù V = 7 V R2 and R4 are parallel, then these are in series with R3, then this whole system is in parallel with R1. I need

32. ## chemistry

The pH of a 1.00 10-3 M solution of pyrrolidine is 10.82. Calculate Kb. i keep getting anumber that is ^ (positive) and that's way to big....

33. ## physics

If sigma(t)^2 denotes the standard deviation in the quantity t^2, show that sigma(t)^2=2tsigma(t) I don't even know where to begin... help plzz

34. ## English

I am doing my essay on drugs use among teens I need someone one to look at my thesis here is my out line. and i need a introduction and conclusion. Thesis: in today society drug use among teenagers is becoming more crucial for society. Outline for Drug use

35. ## Algebra 2

I need some help with my radical equations. I would really appreciate some aassistance.

36. ## physics

write down the uncertainty in the volume of the cylinder (3.36*10^-2) write down the minimum uncertainty with which the volume of the cylinder can be determined (1.79*10^-2) it says to compare these values and discuss briefly. I figured out how to find

37. ## Physicis

Given: Two teams of children are well-matched, and they pull on the rope with exactly the same force. They have placed a 65n weight at the center of the rope. The teams first pull with 750n of force each, then in an heroic effort to straighten the rope,

38. ## Chemistry

How is polonium-210 used in anti-static products? Why is its presence in commercial products (eg. anti-static hair brushes) a concern?

39. ## 10th grade physical science

you are doing a six day tour ofthe coast of south africa. you fly from jhb to cape town in cape town you join a luxury bus tour which takes you via george along the gardens route to p.e then further along the coast to east london ending in durban from

40. ## math

solve the following two equations algebraically. 4x+3y=12 4x-y=4 give the coordinates of intersection.

41. ## Posting

I keep trying to post a question about chemistry and the site keeps telling me that there is an error because I am trying to put in a link to a website. This is not true! I tried to contact the website, and put in my question there. Can someone from this

42. ## Micro Economics

Economists believe that resources should be used as efficiently as possible to 1. achieve society's goals 2. eliminate scarcity 3. reduce inequity 4. do all of the above

43. ## math

solve each equation for 0=/

44. ## civics (history)

Miranda v. Arizona case how is the 14th amendment implicated in this case? how did the court go beyond its usual practice in coming to a decision?

45. ## Physics

A hollow plastic sphere is held below the surface of a freshwater lake by a cord anchored to the bottom of the lake. The sphere has a volume of 0.600m^3 and the tension in the cord is 840N . What is the mass of the sphere? And Calculate the buoyant force

46. ## Child Care

Disciline refers to behaviors that are A. expected. B. self-regulated. C. harsh D. punitive. my answer is B. CAN YOU TELL ME IF I AM CORRECT

47. ## Science/chemistry

Could you please check these answers I don't understand #4 could you give me a link or you can try to help me. Thanks: 1. Identify what all organic compounds have in common, and list the four principal classes of organic compounds. Answer: Cabohydrates,

48. ## physics

A hollow plastic sphere is held below the surface of a freshwater lake by a cord anchored to the bottom of the lake. The sphere has a volume of 0.600m^3 and the tension in the cord is 840N . What is the mass of the sphere? is this how i would find the

49. ## Chemistry

We are currently studying significant digits/figures. I was asked to add 150 ml with 76.9 ml, plus 209 ml plus 0.036 ml. The book says the answer is 440, but I got 435. (the complete answer, without applying the significant digits rule is 435.936) How did

50. ## college math

is the integral of 1/x^2, 2x ln of the absolute value of x^2?

51. ## accounting

1) Straight-Line Method 2) Declining-Balance Method 3) Double-Declining-Balance Method 4) Sum-of-the-Year's digits Method What are the main characteristics of each method and in what situation would you use each of these methods?

52. ## AED

I need help bad with the following Use at least three sources—other than the text for this course—to support your plan. Construct either a 1,050- to 1,400-word paper or a 15- to 20-slide Microsoft® PowerPoint® presentation (with presenter’s notes),

53. ## french

J'adore = i love J'aime = i like ????????????? Je n'aime pas = I don't like Je déteste = I hate what is a neutral opinion?

54. ## English

Can someone Please heip me with my Punctuation and make sure this process paragraph makes senes. Thank you! You can learn how to tie a necktie following these steps. To get started, you will need to select a necktie of your choice and stand in front of a

55. ## math

Solve by elimination method. 0.3x – 0.2y = 4 0.5x + 0.5y = 85/19

56. ## History

Are these true or false: 1. Thoreau argued that the legitimacy of democratic laws demanded obedience and represented a higher law than one's indiviudual philosophies or ethics False? 2. The wave of national uncertainy and secularism in the early 19th

57. ## careers

Is it true majoring in history is a non-traditional field for women?

58. ## ecology

Why do organisms with the widest limits of tolerance, for most factors, will be the widest distributed?

59. ## math/ cal

how do you integrate sin (x^2) dx?

60. ## Physics

How can you prove that acceleration due to gravity is the same in a resting and moving frame?

61. ## Social Studies (Mrs. Sue I redid the 4 paragraphs)

I need someone to check this over thanks. I'm in 9th grade could you please give me a letter grade thanks City Goes Hungry Supporting this article will be very difficult because St. Louisans aren't getting any money from the state lawmakers. But on the

62. ## Chem

Another confusing significant digit problem. I added 36.6 and 2.4, and divided the result by 4.803. The book says the answer is 7.91, but I don'[t see how that could be, since the lowest number of significant digits in the problem is two (2.4). I think the

For every 100 cars that enter the entersection from A, 30 cars head towards B, 40 cars head toward C, and 30 cars head towards D. If 60 cars enter the entersection from A, how many head toward B? Explain, thanks

64. ## Chemistry

2. Calculate the volume for the following object If you know that the object has a mass of 24 grams and the density is 12 g/ml. I tried to get rid of the 24 by multiplying it on both sides, and dividing on both sides, but neither worked. What will then?

65. ## Biology

Where and how are tree seedlings raised?

66. ## Algebra

d) Suppose you want to add a sprinkler system, and the location of one section of the sprinkler line can be described by the equation y= -1/2x -4; this is what I got 4+y= -1/2x-4+4; y=4 and -1/2x + 1/2 making x=0 (0,4) is this correct?

67. ## science

When the roller coaster is at the top of the loop, why doesn’t the person fall off the roller coaster? What forces are acting on the person when the roller coaster is going round the loop? Is it gravitational force and normal force?

68. ## algebra

[x+2] [x+2] [x+3] [+p/3] [x-3] [x+3] [x+9] [3x+xy-2xy][x+2y] [2x-5y][3x-2xy+7y] [2x-y]-[x+y] [0.59-0.3b][0.25-ab+0.5b]

69. ## Marcoeconomics

According to the formula, Bond price= y/r so bond price has a inverse relationship with interest rate.i.e. interest rate increases, bond price decreases. But why does it contradict with this demand-supply anysis: r(interest rate increases)--> returns from

70. ## Physics

please check these for me Which of the following is not a fluid? a. carbon dioxide b. hydrogen c. seawater d. wood D Which of the following statements is not correct? a. a fluid flows b. a fluid has a definite shape c. molecules fo a fluid are free to move

71. ## Algebra

my question is:Suppose you want to add a sprinkler system, and the location of one section of the sprinkler system le can be described by the equation: y= -1/2x -4, this is what I got 4+y= -1/2x - 4 +4, 4y= 1/2x -1/2x; y=4 and x=0 making the answer (0,4).

72. ## finances

E X E R C I S E S Exercise 11.1 The child and family government benefits seminar was such a success that Advocates for Children will conduct a second seminar in an adjoining community. The executive director decides that this second seminar will attempt to

73. ## English

What characters in Lord of the Flies had physical defects? I couldn't think of any, unless you can't being nearsited (Piggy) as a physical defect, or obesity.

74. ## World History 201

I have a homework assignment due tomorrow consisting of true/false questions. Would someone please review my answers and see if I am correct. Thanks. 1. Although women in ancient India were not priests, they were often chosen to teach the importance of the

76. ## Statistics

Using the below information calculate the conditional probability of C given each of the age groups, or P(C/D), P (C/E), etc. Compare these probabilities and speculate as to which age groups seem more likely than others to have been (according to the legal

77. ## govt.

How does the great penitentiary rivalry continue to shape and influence american thinking about the prison systems purpose?

78. ## English

Which one of these sentences uses pronoun correctly? a. Please give Paul and I your undiv ided attention. b. Jacob and me are going to set a meet ing date. c. Carol told Sylvia and he the good news. d. Send the package to Tanya and him.

79. ## physics

write down the uncertainty in the volume of the cylinder that you calculated in part 4 of the error analysis (i got 3.36*10^-2). Also write down the minimum uncertainty with which the volume of the cylinder can be determined. Compare these two values and

80. ## physics/measurements

how do you compute the uncertainty in the volume of a block?

81. ## Chemistry

Consider 57.5 mL of a solution of weak acid HA (Ka = 1.00 10-6), which has a pH of 3.800. What volume of water must be added to make the pH = 6.000?

82. ## Math

Jerome estimate that the total number of people for the past 2 years visiting the aquarium is 900,000. Gina estimated it to be 870,000. Write a number sentence to show how Jerome found his estimate.

83. ## Physics

Calculate the acceleration of a Porsche when he goes from 0 miles/hr to 40 miles/hr in 5.6 seconds. (should I convert 40 miles per hour to miles/second?)

84. ## English

I'm trying to come up with a title for my essay and it can't be more than four words? The topic was "war as a social disease". Everything that I come up with is longer than four words? Any ideas on how I can go about this. I hate when their is a limit of

85. ## Child Care

In order to learn to respect others and devlop healthy relationships, children need to A confront people with different idesa. B. develop strong self-esteem. C. be told what to think. D. learn to gain control over other children. I pick the letter B.

86. ## Algebra

How do I write an equivalent expression using radical expressions for this: (a^2b^2)^1/9

87. ## Quick Spanish

¿Qué peiensas? 1. ¿Tienes pelo castaño? 2. ¿Cómo son tus amigos? Not quite sure what these questions would translate to. Please help.

88. ## French

Bad thing happened, you may remember my other post about what does La Route du Rhum mean but anyway... I was at the library and got all this information but my time ran out and the computer logged off so I wasn't able to same it. I know wherei got most of

89. ## Jiskha in General

Are some of the people on this site teachers? How do they have time to answer our questions? Don't they have to grade papers and such? I'm just curious and grateful that some people are willing to always be on here.

90. ## government

How a bill becomes a law?

91. ## Healthcare

I need some help with find information on what are the implications for patients? What types of reform efforts are being implemented to improve caregiver’s socialization skills? The socializations process of caregivers. Will those reforms efforts be

92. ## college algebra

Translate to an algebraic expression; the product of 48% and some number; use y to represent some number.

94. ## To: Carol -- economics

I've removed your post about researching nurses salaries. You've given us no idea how much of this complex assignment you've done nor how you'd like us to help you. Please repost when you can supply that information.

95. ## math

solve for 0=/

96. ## Writing/ Research

In Katz ( Katz vs Olmstead), why did Douglas write a concurring opinion? what is the basis of his opinion? Do you agree or disagree with the opinion and why?

97. ## math

A machine is either working (state 1) or not workind (state 2). If it is working one day the probability that it will be broken the next day is 0.1. If it is not working one day the probability that it will be working the next day is 0.8. Let Tn be the

98. ## 10th grade physical science

you are doing a six day tour ofthe coast of south africa. you fly from jhb to cape town in cape town you join a luxury bus tour which takes you via george along the gardens route to p.e then further along the coast to east london ending in durban from

99. ## statistics

The following contingency table of frequencies is based on a five year study of fire fatalities in Maryland. For purposes of clarity, columns and rows are identified by the letters A-C and D-G respectively. Blood Alcohol Level of Victim Age A B C 0.00%

100. ## Math

I need help with this partial fraction problem. Find the indefinite integral of (-5x^3+5x^2-5)/(x^4+X^3). I got -5(log(x+1)+(1/x)-(1/(2x^2)).

101. ## CALCULUS

show that f(x) = x^2-1 (x is greater than and equal to 0) and g(x) = root(x-1) (x is greater than and equal to -1) are inverse functions. when i try f(g(x)) = x and g(f(x)) = x to show that the two functions are inverses it doesn't work because i am not

102. ## physics

can anyone show me how to do this? A container of gas is at a pressure of 3.7 * 10^5 Pa. how much work is done by the gas if its volume expands by 1.6 m^3? thanks

103. ## English Literature

How does J.B Priestly encourage the audience to agree with the Inspector’s view that “We are members of one body” as apposed to Mr. Birling’s view that “a man has to make his own way”?

104. ## grammar

The antecedent in the following sentence is students: Students in online classes have to be organized to keep up with their assignments.

105. ## math

how do you subtract 10-1 1/2

106. ## Cultural Diversity

What are the current changes in U.S. policies concerning the treatment of Muslim and Arabic Americans?

107. ## Cultural Diversity

"According to current research and news reports, what are some of the changes the U.S. has make to policies concerning the treatment of Muslim and Arabic members of society?" Axia College Week 5 syllabus ETH125 I have checked on Google and only finding

108. ## Cultural Diversity

Thank you Ms.Sue, That's what I thought since I have checked online and come up with nothing new either.

109. ## Statistics

Using the information presented calculate the following probabilities: Blood Alcohol Level of Victim A B C Age 0.00% 0.01-0.09% 0.10% D 0-19 142 7 6 155 E 20-39 47 8 41 96 F 40-59 29 8 77 114 G 60 over 47 7 35 89 Total 265 30 159 454 A) P(A or D) B) P(B or

110. ## government

what is the economic stimulus package and what implications would it have on peopleof this country?

111. ## college math

how do you integrate (cos^2 x)^4

112. ## Math-Functions

How would you solve the following equation when x= -6 x=y^2-5y

113. ## Algebra II

How do I evaluate log base 8 of 4?

114. ## gov

are many people happy with the stimulus package

115. ## math

how do you integrate 30x^2/((x-2)(x+3)(x-5)) using partial fraction decomposition

116. ## math

how do you integrate dx/(x^2*(x^2+4)^1/2)?

who was Polk?

118. ## English Ms. Sue

How does will power not change the orignial conflict "war as a social disease versus non-conformity".

Is this the correct abbreviation for instructor (instr)

120. ## math

how do you integrate (3x+1)/(x-1)x^2 dx?

121. ## Child Care

One suggested way to foster both prosocial behavior and self-esteem is the use of A. reasoning B. time-out C. verbal aggression D. role modeling I pick the letter A.

122. ## Algebra

Solve using the addition principle: 2x+9>x+14, x+9-9> 14 - 9, x>5 is this right?

123. ## college math

how do you integrate ln(x^2+1)dx?

124. ## Cultural Diversity

What are current United States changes to policies concerning the treatment of Muslim and Arabic members of society?

125. ## college math

how should I integrate 1/(x^2 +1)^5

126. ## gov

is it hopeful that we will come out of this recession

127. ## finance

How would the following errors affect the account balances and the basic accounting equation, Assets = Liabilities + Owners' Equity? How do the misstatements affect income? o The purchase of a truck is recorded as an expense instead of an asset. o A cash

128. ## Healthcare

I need some help with a list of caregivers perpectives on health.

129. ## animal biology

What is meant when a cnidarian colony is described as polymorphic? What does it mean when an organism is described as colonial?

130. ## Science

ionic compounds for the following: calcium chloride calcium oxide sodium oxide sodium carbonate aluminium carbonate calcium sulfate sodium nitrate sodium sulfate aluminium oxide aluminium hydroxide

131. ## biology

Why are coral reefs generally limited in distribution to shallow marine waters?

132. ## Political Science

Can you suggest good topic/s for my concept paper in PoliScie? Help me please. Thanks!

133. ## Math

i know the formuula for density is d=m/v. is the formula for mass then m=dv? what about the formula for volume? is that v=m/d?