Questions Asked on
April 21, 2007

  1. physics - sound level

    The source of a sound wave has a power of 2.50 µW. Assume it is a point source. (a) What is the intensity 6.70 m away? I used I = Power / 4*pi*r^2 and found I to be 4.43x10^-9 W/m^2 (b) What is the sound level at that distance? Sound level = 10 dB*log

    asked by COFFEE
  2. physics - sound level

    For two sounds whose sound levels differ by 69 dB, find the ratios (greater value / smaller value) of the following values. (a) the intensities Intensity Final/Intensity Initial = log^-1 (69 / 10) = 7.9x10^6 (b) the pressure amplitudes (c) the particle

    asked by COFFEE
  3. Physics HELP!!!!!!!!

    Suppose a monatomic ideal gas is contained within a vertical cylinder that is fitted with a movable piston. The piston is frictionless and has a negligible mass. The area of the piston is 3.06 10-2 m2, and the pressure outside the cylinder is 1.02 105 Pa.

    asked by Mary
  4. Sequence and series

    Do you know the difference between a sequence and a series? Graph the terms of an arithmetic series. Remember the domain is the set of natural numbers, not the set of real numbers. What type function do you see? Graph the terms of a geometric series.

    asked by Tony
  5. Maths

    Hi Can someone give me a help in finding maths quiz websites for Ket Stage 3

    asked by Fahad
  6. Nutrition

    Can you help with this question? Please give your opinion. Appropriate cooking methods are cost-efficient because: 1.food expansion is minimized. 2.waste due to undercooked food is minimized. 3.nutrients are conserved. would 1 be the best answer? I am not

    asked by Paula
  7. French-for SraJMcGin.

    Thank you so much!!!! I'm really sorry that I could not post back a.s.a.p to all your posts.Thoses posts were SO Helpful! Don't worry about the links, because I have searched for it and it was brilliant! I don't have a problem with memorising the vocabs, I

    asked by Pauline
  8. Spanish

    Our teacher gave us this quote "the one who got away" and we are supposed to figure out what it means. If anyone in the class does the entire class gets to go to our local Mexican restaurant for lunch!! Please help! It is pretty obvious what it means, in

    asked by Andrew
  9. chemistry

    which of the following would be expected to have the lowest freezing temperature? a. Ca(NO3)2 b. NaC2H3O2 c. CuSO4 d. HC2H3O2 e. C2H5OH per what? per gram? per mol? Any could have the lowest freezing point if I put a cup of any one and a scant amount of

    asked by mary
  10. algebra help please

    The U.S. population in 1990 was approximately 250 million, and the average growth rate for the past 30 years gives a doubling time of 66 years. The above formula for the United States then becomes P (in millions) = 250 times 2( y-1990)/66 What will the

    asked by carry
  11. math

    I need help figuring out these two questions on euations with integers. -5x+20=-60 2x-3=-2 thank you so much for first: subtract 20 from both sides, simplify, then divide both sides by -5 for second: add 3 to both sides, simplify, then divided both sides

    asked by Amy L.
  12. chemistry

    the solubility of AgCl in HCl is a. low, as Cl- ions cause an equilibrium shift towards the solid form b. low, as Ag+ has already reacted with Cl- c. high, as HCl readily ionizes d. high, as AgCl can then form e. high, as H2 forms, then escapes (a) The

    asked by Mary
  13. Early Childhood Ed.

    I have a question but think I know the right answer. Just need someone to verify. Which is not an example of the typical toddler behavior? 1.toddlers are fairly capble of self-feeding 2.toddlers don't like food mixtures 3.toddlers show decided food

    asked by Elaine
  14. ALGEBRA

    A triangle has sides 3x +7, 4x - 9, and 5x + 6. Find the polynomial that represents its perimeter. Am I suppose to just add these together to get the perimeter 3x+7 4x-9 5x+6 12x+4 that's how easy it is.

    asked by TOMMY
  15. algebra

    does log base of 4 sqrt(t/s)=1/2log base of 4 t - 1/2log base of 4s? sqrt=square root thanks yes yah thanks!

    asked by Fiona
  16. Chemistry

    Questions with what I think correct: -Has the largest anion.D -Is the most electronegative.A -Has the highest bonding energy in its diatomic molecule.B -Is a liquid at room temperature in tis free state.C Chooses: A. Fluoride B. Chloride C. Bromide D.

    asked by Ryan
  17. Chemistry

    I have no idea how to do this problems can somebody help me: 1.How many mL of and oxygen gas can be produced form the termal decmpositon of 0.340 g of hydrogen peroxide at 700°C and 755 mm Hg? 401 mL 803 mL 1200 mL 1610 mL 2.How many mL of oxygen gas at

    asked by Ryan
  18. Chem

    Which coordination compound will most likely form a precipitate when treated with silver(II) nitrate (aqueous)? [Cr(NH3)3Cl3] [Cr(NH3)6Cl3] Na3[Cr(CN)6] Na3[CrCl6] I tried the solubility rules, but that didn't work out. Any help would be great. I made a

    asked by Londy
  19. Chemistry

    1.Which diatomic molecule below would be useful in saying good-bye? O2 N2 I2 Ta2 Li2 2.Which element is best for use in flash bulbs? Mn Mg Cs Ca Sr

    asked by Lisa
  20. Algebra, Solving equations

    I'm stuck with this equation: y = (4x-1)/(2x+3) We're working on inverses, which I understand, but my mind is blanking on how to solve this for x. Thanks in advance, Amy :) after you interchanged the x and y variables, and expanded you should have had x =

    asked by Amy
  21. science

    Hydrogen Cyanide (boiling temperature 26 degrees Celsius) is an important chemical for the production of nylon and various transparent plastics. It is produced on an industrial scale by the oxidation of methane in the presence of ammonia. The equation

    asked by katie
  22. maths

    2x2/5y2 what is supposed to happen here?

    asked by sonia
  23. French: Pauline: verbes

    As a beginner, you should be beginning with regular verbs. I also have exercises, should you wish to do any of them.

    asked by SraJMcGin
  24. science

    Which of the following is a example of a irriversible change. a)Disssolve salt in water b)Freezing water C)Mixing water-colour Which do you think you can't separate? Can you separate salt after it is dissolved in water? I think I could evaporate the water

    asked by Rohit
  25. History- Nazi Germany

    I was wondering if any one could find a picture of a Nazi woman called-Gertrude Schlottz-Klink. thanks Thank you for using the Jiskha Homework Help Forum. If you misspelled the name, here is what I did find: 1. Click Here: Check out "Gertrude

    asked by Jessica10
  26. geography

    explain how partial melting and fractional crystallisation produce felsic magma from more maficparent magma Would this help: http://en.wikipedia.org/wiki/Fractional_crystallization_%28geology%29

    asked by bob
  27. geography

    discuss how interactions between the Earth systems affect the climate Mary or Bob or whoever, Please note that we don't do students' homework for them. Our tutors try to give you the information to help you complete your assignment on your own. If there's

    asked by mary
  28. Chem

    How come Silicon differs from the trend of increasing electron affinity as we move to the right in a period? Is it because more energy is released to fill in the last orbital? Or is it something else? I'm not sure I agree that Si is out of place. As we

    asked by Steve
  29. chemistry

    which of the following would be expected to have the lowest freezing temperature? a. .1 M Ca(NO3)2 b. .1 M NaC2H3O2 c. .1 M CuSO4 d. .1 M HC2H3O2 e. .1 M C2H5OH Here is what you do Mary. delta T = Kb*i*m Kb is the same for all. m is the same for all. i is

    asked by mary
  30. Chemistry

    There are 3 known isotopes of Hydrogen and 3 stable isotopes of oxygen. How many types of water molecules would these produce? Is it 3 ?

    asked by Jessica
  31. Chemistry - Buffers

    A buffer is formed by adding 500mL of .20 M HC2H3O2 to 500 mL of .10 M NaC2H3O2. What would be the maximum amount of HCl that could be added to this solution without exceeding the capacity of the buffer? A. .01 mol B. .05 mol C. .10 mol D. .15 mol E. .20

    asked by alexa
  32. Chemistry -Thermodynamics

    1. Cl2(g) -> 2Cl(g) 2. H2(g) at 5.0 atm -> H2(g) at 1.0 atm 3. sublimation of solid CO2 4. 2H2(g) + O2(g) -> 2H20(g) 5. PCl5(g) PCl3(g) + Cl2(g) A. The change in entropy will be positive. B. The change in entropy will be zero. C. The change in entropy will

    asked by alexa
  33. Math

    Carl's hands trembled as he stood in front of the safe and unfolded the crumpled piece of paper holding the combination that would open the safe. "Rats!' he moaned. The combination was written in the form of a riddle. The last number was described in the

    asked by Sam
  34. calculus

    a particle moves along the curve xy=10. if x=2 and dy/dt=3, what is the value of dx/dt. i'm guessing this is something to do with parametric equations. if x is 2, then y=5. but how do i get dx/dt. you have to differentiate the equation with respect to t so

    asked by Anonymous
  35. Chemistry - Periodic Trends

    For the isoelectronic series S2-, Cl-, Ar, K+, and Sc3+, which species requires the least energy to remove an outer electron? thanks They all have the same number of electrons (40) in the same shell arrangements, but S(2-) has the least nuclear charge.

    asked by alexa
  36. Math

    Graph each question by plotting ordered pairs x=2 it's hard to describe this one.. but it would be a vertical line where 2 is along the x-axis. so it would look like the y-axis, only 2 spaces over.

    asked by Megna
  37. reading

    what is the meaning of the " as if they already stood aghast at the bloody work they would look upon form the poem Paul Revere Where does this come from? Context is needed. ?? It comes from the poem Paul Revere by Longfellow. Then line before is And the

    asked by Ashley
  38. chem

    an energy value of 3.313x10^-19 joules is needed to break a chemical bond. what is the wavelength of energy needed to break the bond? (the speed of light = 3.00x10^10 cm/sec; planck's constant = 6.636x10^-34 J . sec is there a formula i'm missing? Formula

    asked by ashley
  39. chem

    a 10.0% sucrose solution has a density of 2.00 g/mL. what is the mass of sucrose dissolved in 1.00 liter of this solution? thanks, mary Well, in a liter, there are 2000 grams (from density), and 200 of those are sucrose.

    asked by mary
  40. Environmental Science

    Can someone please like help me? :') Mack, what is your question? We will not give you the answer but I will try to find you sources where you can find it. I checked your previous multiple choices posts. It is not possible to say if they are correct (best

    asked by Mack
  41. thermodynamics?

    calculate the number of grams of glycerol, C3H5(OH)3 (MW=92.1 g/mol), that must be dissolved in 520 grams of water to raise the boiling point to 102.00 degrees Celsius. this whole chapter really lost me. delta T = Kb*molality delta T = 2 degrees. Kb =

    asked by chris
  42. Environmental Science

    What is another cause of artificial eutrophication? Since you haven't told us what other causes are, it's impossible for us to find "another cause." Please tell us the causes you've found -- and we'll try to help you. fertilizer from farms, lawns, and

    asked by Mack
  43. nuclear chem

    which of the following choices correctly describes the decreasing ability of the radiation to penetrate a sheet of lead that is 3 inches thick? A. alpha particles > beta particles > gamm rays B. gamma rays > alpha particles > beta particles C. alpha

    asked by james
  44. Environmental Science

    Can someone please help me match up my vocad since I've gotten them all wrong in class the other day? 1.__Mississippi River 2.__Area above an aquifer 3.__Bottled water 4.__Bacteria 5.__multiple sources 6.__fertilizer runoff 7.__law designed to improve

    asked by Mack
  45. social studies

    a person who owned and contolled all the land in a colony Calab, that depends on what colony it was. Some were the property of the crown; some were given to people the king wanted to favor. Others were the property of the people who lived there.

    asked by calab
  46. Math

    The perimeter of a semicircle is 72 cm. Find the raduis of the semicircle and then find its area Consider the full circle: perimeter 144 radius= perimetercircle/2PI areacircle= PI*rad^2 areasemicircle= 1/2 area circle

    asked by Anonymous
  47. Math

    180 ml of a mixture of water and alcohol with 90% alcohol concentration is mixed with 70 ml of pure water. what is the alcohol concentration of the new mixture? Do the following: 1) Find out how many ml of alcohol was in the first mixture. (What is 90% of

    asked by julia
  48. math!!!

    can you please check my work 19mm=? m ?=.19??? .017km=? cm ?=1700? 61500cm/min =? km/h ?=.615? thank youuu! .019 (missed a decimal space) 1700 is correct The last one is a little trickier. First, figure out how many km per minute you are moving: .615

    asked by George
  49. Chemistry

    We did a lab for acid-base titrations, and I'm having trouble with my post lab questions because I had trouble with acid-base reactions and titrations in the first place! "Calculate the molar amounts of NaOH used in the reaction with the HCl solution and

    asked by Rachel
  50. Law ( contract)

    Frank and fanny farmer have been married to 10 years. On march 1, 2002 fanny farmer decides to go on “strike” she refuses to do any farm chores or chores around their home. She puts up a big sign by the road and writes in bold letters “ FANNY FARMER

    asked by Bob
  51. Environmental Science

    I'm having diffulculty finding the answer through this passage. Could you please help me out? Industry accounts for 19 percent of water used in the world. Water is used to manufacture goods, to dispose of waste, and to generate power. The amount of water

    asked by Mack
  52. Chemistry

    Sorry for posting this again, I don't know if the question was skipped or not, but I was just wondering if I could get some help on this... thanks. There are 3 known isotopes of Hydrogen and 3 stable isotopes of oxygen. How many types of water molecules

    asked by Jessica
  53. english

    what are the pros and cons of joining "netville 2" a computer company that came to your neighbourhood. We will be happy to critique your thinking on this. thanks im having trouble thinking of cons. The only thing i have for cons are: hidden fees and

    asked by barry
  54. Calc

    Find the exact total of the areas bounded by the following functions: f(x) = sinx g(x) = cosx x = 0 x = 2pi I set my calculator to graph on the x-axis as a 2pi scale. The two functions appear to cross three times between x = 0 and 2pi. (including 2pi) Now,

    asked by Sarah
  55. science

    i need to rearrange the following equations, to make x the subject . r = sx^2 2t and 6y = 9 – 3x can some 1 help me im realy stuck. i need to work it out step by step. the 2t is meant 2 be under sx^2 meaning dived by r= sx^2/2t multipy both sides by 2t

    asked by katie
  56. Chemistry-PLEASE help!!!

    1.Which diatomic molecule below would be useful in saying good-bye? O2 N2 I2 Ta2 Li2 2.Which element is best for use in flash bulbs? Mn Mg Cs Ca Sr Magnesium is often used in old time flash bulbs, if they still exist. ] I have no idea on the first. TaTa?

    asked by Lisa
  57. Chemistry

    1.Which of the following elements is likely to have the highest concentration inside a human cell? K Cs Na Rb Li 2.Which of the following has an amphoteric oxide? Be Ca Sr Ba 3.In the following list of metals, the strongest reducing agent is Rb Na Cs K Li

    asked by Ryan
  58. Written Communication

    What kinds of unwanted reactions might you get from readers of your messages? What steps would you take to ensure that the purpose of your message (whether informative, negative, or persuasive) is conveyed to your readers? It's extremely important to

    asked by Frankie
  59. Repost: Science (Lilly)

    Written Communication - Lilly, Saturday, April 21, 2007 at 8:48pm What one thing is required for a rock to be called a sedimentary? Written Communication - Lilly, Saturday, April 21, 2007 at 8:52pm I know that "sedimentary rocks are formed when chemical

    asked by Writeacher
  60. chem

    frozen carbon dioxide, CO2. what is dry ice

    asked by DrBob222
  61. Project Management

    Can you please let me know if it is true or false that Gantt Chart is good for planning but not an effective tool for control.

    asked by Bob
  62. Matter Grade 3

    I have to give an ex of a solid, liquid and gas and write a sentence telling what I know about the shape and volume of each. My ex for solid is rock;liquid is juice and gas is air. How would I make sentences describing shape and vol. For rock i did: The

    asked by Jackie
  63. Calc 121

    How do you integrate using substitution: the integral from 1 to 3 of: ((3x^2)+(2))/((x^3)+(2x)) There is a trick to this one that grealy simplifies the integral. Let u = x^3 + 2x. Then du = (3x^2 + 2)dx The integral then bemoces just the integral of du/u,

    asked by Me
  64. CHemistry

    im not sure how u solve these types of problems... How many moles of NaOH are contained in 200ml of a 0.1M of NaOH? How many grams of NaOH are contained in 500ml of a .5M solution of NaOH? A 0.1 M solution has 0.1 moles of the solute NaOH per liter. You

    asked by Phil
  65. Math

    The license fee for a car varies directly with the value of the car. The fee for a car that is valued at $19,500 is $292.50. a) What is the constant of proportionality? b) Write the equation that shows the license fee as a function of the value of the car.

    asked by Merl
  66. Algebra

    Can someone please check my answers. 1. Solve. –7x + 1 + 8x = x + 1 A) Identity B) No solution C) 1 D) 0 My answer: A) Identity 2.The length of one of the equal legs of an isosceles triangle is 8 cm less than 4 times the length of the base. If the

    asked by Noah
  67. Calc 121

    Okay, how would you go about finding the area of a curve from 1 to 4, when y=2x+(2/(x^2))?? It's not like the problem I asked before because here, you cannot use substitution. I tried using 2x for u and x^2 for du but it won't simplify into a ln problem or

    asked by Me
  68. Blobs....

    I would like to learn more about Blobs. Thank you for using the Jiskha Homework Help Forum. Are you referring to the Minichip games? Let's begin with a definition: Main Entry: [1]blob Pronunciation: 'bläb Function: noun Etymology: Middle English Date:

    asked by Tyler
  69. Math

    Solve 2x-y+3z=8 x-6y-z=0 -6x+3y-9z=24 Did you notice that your third equation has the same normal as the third one? So visually I see two parallel planes intersected by third non-parallel plane, namely the second equation. So solve equations 1 and 2, and

    asked by Lily
  70. chemistry

    Nitrogen gas, N2, is usually a very inert gas and thus, is often employed in dry boxes. However, it would be a poor choice for use in a dry cell with which of the following substances? A) uranium metal B) Cu/Sn alloys C) Li metals D) Ca metals E) none of

    asked by blobface
  71. chemistry

    Can someone help me with this homework problem? Which of the following is the best explanation as to why lithium is the strongest reducing agent in the alkali metals? A) relatively high charge density of Li B) lowest ionization energy of the metals C) most

    asked by ninjaturtle
  72. chemsitry

    What ions are very important for the proper fuctioning of biological systems such as nerves and cells? A)alkali earth metals B)hydrogen ions C)oxygen ions D)nitride ions E)alkali metal ions

    asked by ninjaturtle
  73. physics - doppler effect

    Two identical tuning forks can oscillate at 329.6 Hz. A person is located somewhere on the line between them. The speed of sound in the air is 343 m/s. Calculate the beat frequency as measured by this individual under the following conditions. (a) the

    asked by COFFEE
  74. algebra

    I have been working this one for awhile and have become more confused. Please assist. Problem: Find two consecutive odd integers such that 5 times the first interger is 12 more than 3 times the second. The key thing is to realize that odd numbers, just

    asked by ken
  75. chemistry

    which would be the best anwser here? my guess was D but i wanna be sure Ammonium nitrate is sometimes used as a high explosive which reason best explains this? A)extremely water soluble B)contains ammonium ions C)excellent commerical fertlizer D)contains

    asked by smartypants
  76. CHEMISTRY HELP!!!!!!!!

    How many grams of KCl are produced by the thermal decomposition of KClO3 that produces 25mL of O2 at 25 degrees and at 1 atm? A)0.0508 B)0.0762 C)0.0835 D)0.125 what is the anwser and what equation would i use to get the anwser? Write the balanced equation

    asked by smartypants
  77. chemistry help ASAP

    Water is often instrumental in promoting disproportionation reactions however, it cannot itself disproportionate? IS THIS TRUE OR FALSE?????

    asked by CHEMgurl
  78. CHEMISTRY

    What is the Lewis dot structure for the HYDRIDE ion? A)H:- B)H+ C)H' D)H3O+ E)none It's hard for me to read the dots but I THINK answer a) looks like this? H:- If so that is the Lewis dot structure for the hydride ion

    asked by CHEMgurl
  79. CHEMISTRY

    What is NOT is good laboratory method for preparation of oxygen gas? is the anwser here C or am i wrong A)photosynthesis B)electrolysis of water C)catalytic decomposition of hydrogen peroxide D) thermal decompositon of KClO3 Photosynthesis is not a good

    asked by CHEMgurl
  80. chemistry

    Which if the following statements concerning complex ion Co(en)2Cl2+ is true? en=NH2CH2CHNH2 A)the geometric isomers of the complex ion have identical chemical properties B) the complex ion exhibits cis an dtrans geometric isomers but no optical isomers

    asked by gina
  81. CHEMISTRY HELP NOW PLZ!

    which of the following coordination compounds will most likely form a precipitate when treated with an aquesous solution of silver(l) nitrate? A) [Cr(NH3)2CL3] B) [Cr(NH3)6]Cl3 C) [Cr(NH3)Cl]SO4 D) Na3[Cr(CN)6] E) Na[CrCl6] i think its either a or b but i

    asked by gina