lyne

Popular questions and responses by lyne
  1. chemistry

    Nitrogen (N2) and hydrogen (H2) react to form ammonia (NH3). Consider a mixture of six nitrogen molecules and six hydrogen molecules in a closed container. Assuming the reaction goes to completion, what will the final product mixture be? number of NH3

    asked on January 23, 2009
  2. chemistry

    The element rhenium (Re) has two naturally occurring isotopes, 185Re and 187Re, with an average atomic mass of 186.207 amu. Rhenium is 62.60% 187Re, and the atomic mass of 187Re is 186.956 amu. Calculate the mass of 185Re. am i supposed to multiply the

    asked on January 5, 2009
  3. chemistry

    Ca(s) + Br2(l) --> CaBr2 is synthesis my teacher also said that the cause of the reaction is stable electron configuration is that the same thing as the electrolytes one

    asked on January 20, 2009
  4. chemistry

    A student prepared aspirin (C9H8O4) in a laboratory experiment using the following reaction. C7H6O3 + C4H6O3 C9H8O4 + HC2H3O2 The student reacted 2.00 g salicylic acid (C7H6O3) with 2.67 g acetic anhydride (C4H6O3). The yield was 2.00 g aspirin. Calculate

    asked on February 4, 2009
  5. chemistry

    a.Write the balanced chemical equation for the reaction of methane and sulfur. (Type your answer using the format CO2 for CO2. Use the lowest possible coefficients.) 1CH4 + 4S --> 1CS2 + 2H2S (b) Calculate the theoretical yield of carbon disulfide when

    asked on January 27, 2009
  6. chemistry

    Ca + Br2 --> CaBr2 its synthesis and the reason the reaction happens is stable electron configuration but i don't understand why. Responses chemistry - DrBob222, Wednesday, January 21, 2009 at 10:06pm Synthesis because it's two elements combining to form a

    asked on January 21, 2009
  7. chemistry again :)

    A compound containing only sulfur and nitrogen is 69.6% S by mass; the molar mass is 184 g/mol. What are the empirical and molecular formulas of the compound? i solved for empirical and got a 1:1 ratio so it would be SN. for the molecular do i take

    asked on January 2, 2009
  8. chemistry

    Hydrogen cyanide is produced industrially from the reaction of gaseous ammonia, oxygen, and methane. 2 NH3(g) + 3 O2(g) + 2 CH4(g) 2 HCN(g) + 6 H2O(g) If 5.00 x 10^3 kg each of NH3, O2, and CH4 are reacted, what mass of HCN and of H2O will be produced,

    asked on February 1, 2009
  9. chemistry

    The compound adrenaline contains 56.79% C, 6.56% H, 28.37% O, and 8.28% N by mass. What is the empirical formula for adrenaline? i worked the problem out and got C8O3N but its not right..what did i do wrong?

    asked on January 5, 2009
  10. chemistry

    Consider the following unbalanced reaction. P4(s) + 6F2(g) 4PF3(g) How many grams of F2 are needed to produce 114. g of PF3 if the reaction has a 78.1% yield? i tried it and got this 114g PF3 x (mol PF3/87.97g PF3) x (6 mol F2/ mol PF3) x (38g F2/mol

    asked on February 4, 2009
  11. chemistry

    Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation is given below. C7H6O3 + C4H6O3 C9H8O4 + HC2H3O2 What mass of acetic anhydride is needed to completely consume 3.60 x 10^2 g salicylic

    asked on January 23, 2009
  12. history

    I have to write an essay on the role Germany had in World War 1 between 1914 and 1920. I need to have three key points but I can only think of one. So far i have a paragraph about how Germany attacked the Lusitania and killed innocent civilians. -would

    asked on April 30, 2009
  13. chemistry

    Chlorine dioxide, ClO2, has been used as a disinfectant in air conditioning systems. It reacts with water according to the following equation. 6ClO2 + 3H2O --> 5HClO3 + HCl If 142.0 g of ClO2 is mixed with 33.0 g of H2O, how many grams of the reactant will

    asked on February 2, 2009
  14. chem

    if you were to react 14.00 grams of salicylic acid with 8.50 grams of acetic anhydride, what would your theoretical yield be? the reaction is C7H6O3+C4H6O3--> C9H8O4 + C2H4O2 assuming 1:1 ratio.

    asked on September 1, 2009
  15. chem

    how many grams of a precipitate will form when you mix 45 ml of a 3.5M silver nitrate solution with 45 ml of a 5.4 M magnesium chloride solution i sorted the problem but have no clue how to start

    asked on June 7, 2009
  16. anonymous

    what atoms usually form coordinate covalent bonds i couldn't find this anywhere also i just want to make sure is the electronegativity difference range for polar covalent bonds .4 - 2.1 paulings?

    asked on June 7, 2009
  17. chemistry

    how many atoms of tungsten are in 504.56 g of tungsten(IV)acetate. i attempted this problem but ended up with atoms of tungsten(IV) acetate in tungsten(IV) acetate instead of atoms of just tungsten in tungsten(IV) acetate. please help thanks

    asked on June 7, 2009
  18. chemistry

    list three ions that are iso-electric with potassium +1 please explain i have no clue

    asked on June 7, 2009
  19. chemistry

    The total acidity in water samples can be determined by neutralization with standard sodium hydroxide solution. What is the total concentration of hydrogen ion, H+, present in a water sample if 300. mL of the sample requires 7.5 mL of 2.8 10-3 M NaOH to be

    asked on March 26, 2009
  20. chemistry DRBOB

    Calculate the hydrogen ion concentration, in moles per liter, for solutions with each of the following pH values. pH=1.10 im guessing that this is what i did in my previous question except now i have to do it backwards. but i don't know how to do the

    asked on March 23, 2009
  21. chemistry

    Write a chemical equation showing how each of the following species behaves as a base when dissolved in water a.) O2- i have O2- + H2O --> HO2- + OH- how do i make this right??

    asked on March 19, 2009
  22. chemistry

    how many moles of hydroxide ions are there in 82.35 mL of a 2.164M Sr(OH)2 solution? i understand how to do the math for problems like these, but i don't know how to find the moles of just hydroxide ions.

    asked on March 15, 2009
  23. chemistry

    How many grams of oxygen are required to react with 2.50 g of propane (C3H8) to form CARBON MONOXIDE and water? this is what i did why is it wrong? 2.50 g C3H8 x 1 mole / 44.09 g C3H8 x 5mole O2 / mole = 9.1 g O2 everything cancels to get grams of O2 which

    asked on January 22, 2009
  24. chem

    The term Intrinsic denotes a characteristic or property of some thing or action which is essential and specific to that thing or action, and which is wholly independent of any other object, action or consequence. A characteristic which is not essential or

    asked on January 7, 2009
  25. chemistry

    Calculate the number of C, H, and O atoms in 4.50 g of glucose (C6H12O6), a sugar. okay i did it and i got just the C right and not the H and O help?

    asked on January 5, 2009
  26. chem

    a certain substance strongly absorbs infrared light having a wavelength of 3.75µm. what is the frequency of this light in hertz? i know that i have to use the equation c = frequency x wavelength and that c = 2.998 x 10^8 m/s. how do i convert that to

    asked on January 2, 2009
  27. chemistry

    how do i balance the following(fill in the blanks): 1.) __BF3 + __Li2SO3 --> __B2(SO3)3 + __LiF 2.) __CaCO3 + __H3PO4 --> __Ca3(PO4)2 + __H2CO3 3.) __B2Br6 + __HNO3 --> __B(NO3)3 + __HBr

    asked on December 15, 2008
  28. 9th grade chemistry

    what is the name for CsF? i had cesium flouride but it's wrong... help?

    asked on December 5, 2008
  29. math

    i already asked this question for how to divide (x^2 +2x) / 2x-1 i need to find the quoyient not how to simplify it. I need to use the quotient in order to graph an oblique asymptote. can it not be divided?

    asked on November 15, 2009
  30. math

    how would i do (x^2 + 2x) / (2x-1) thanks

    asked on November 15, 2009
  31. math URGENT

    okay i need to find the domain and range of this z(x) = ãx^2 - 100 (everything is in the square root) so i think i found the domain i got [-10,10] but i don't know about the range i solved for x and got stuck here x=ãy^2 + 100 helppp pleaseee :)

    asked on October 29, 2009
  32. microbio

    how large are bacteria? what are the requirements for autoclaving bacteria

    asked on October 27, 2009
  33. math

    what would the graph of this look like xy

    asked on October 24, 2009
  34. microbiology

    what is the common-source outbreak of the H1N1 flu of 2009

    asked on October 15, 2009
  35. microbiology

    Where and what is patient zero in the H1N1 infection? Use this info to discuss primary infections vs. secondary infections i can figure out the second part if anyone can tell me the first part thanks :)

    asked on October 14, 2009
  36. math

    ok this is kinda stupid but i totally just confused myself with the simplest thing haha okay when doing the FOIL methed to this equation (-7-y)(-7-y) would it be 49 + 7y + 7y + y^2 or no??

    asked on October 4, 2009
  37. science

    are most petri dishes the same size? if so what would the diameter of one be? i need to find the surface area of a petri dish

    asked on October 4, 2009
  38. ..

    are most petri dishes the same size? if so what would the diameter of one be? i need to find the surface area of a petri dish

    asked on October 4, 2009
  39. math

    im solving nonlinear equations they are y = x^2 y - 2 = x so i plugged in the x^2 to get x^2 - x = 2 then i factored out an x to get x(x-1) = 2 now what would i do?

    asked on October 4, 2009
  40. microscopes

    When using a light microscope to look att two hairs crossed over each other... Under low power were both hairs in focus at the same time? What about medium power? What does this tell you about the depth of field as you increase magnification. The answer to

    asked on September 27, 2009
  41. Microbiology

    what is the best resolution of our light microscopes the formula should be RP = wavelength/2NA right?? so my question is which wavelength do i put as the denominator

    asked on September 22, 2009
  42. microbiology

    List 6 uses of microbes both by humans and in mother nature

    asked on September 17, 2009
  43. chemistry

    mole can be abreviated as mol right??

    asked on September 7, 2009
  44. chem

    what VSEPR "shapes" and bond angles do you find Toluene

    asked on September 1, 2009
  45. chemistry

    what ionic compounds could you form from the following? Sodium Calcium Neon Phosphorus Chlorine i have NaCl, CaCl2, Na3P, and Ca3P2 is that all and can neon be used?

    asked on June 6, 2009
  46. chemistry

    my last question is how do you determine the molecular formula of a covalent compound given its formula?

    asked on May 5, 2009
  47. chemistry

    my teacher told me that polar bonds have a difference in elecronegativities of .4-2.1 is that the only way to find if a bond is polar? also how would you find out if the MOLECULE is polar or not? - i think i remember my teacher saying something about

    asked on May 5, 2009
  48. chemistry

    what are structural formulas?? also is this correct hybridization is the setting aside of p orbitals in order to form bonds (pi bonds)

    asked on May 5, 2009
  49. chemistry

    how would you determine the % of ionic/covalent char. in the bond? this is on my test review and don't remember learning it

    asked on May 5, 2009
  50. chemistry

    I have to draw the QMM of CL2C2. For the Lewis structure i think that the two C atoms form a triple bond and the Cl atoms form single bonds. Cl | C'triple bond'C | Cl Therefore i think that the central C atom hybridizes into sp. if this is correct, my

    asked on April 29, 2009
  51. DRBOB

    help with below questions please and thank you

    asked on April 29, 2009
  52. chemistry

    why is COCl2 polar a. different electronegativities b. nonsymmetric c. tetrahedral d. symmetric e. trigonal planar more than one can be chosen also wht is HCN polar a. nonsymmetric b. different electronegativities c. trigonal planar d. linear e. bent f.

    asked on April 29, 2009
  53. chemistry

    I have to draw the QMM of CL2C2. For the Lewis structure i think that the two C ayoms form a triple bond and the Cl atoms form single bonds. Therefore i think that the central C atom hybridizes into sp. if this is correct, my question is how do i know

    asked on April 29, 2009
  54. chemistry

    How do multiple bonds introduce rigidity into molecules? what is meant by rigidity??

    asked on April 28, 2009
  55. chemistry

    what is the duet rule?

    asked on April 28, 2009
  56. chemistry

    when do you need to use the octet rule for lewis structures and when does it not apply i am confused for N2O4 i cant get the rules to work with the structure

    asked on April 20, 2009
  57. chemistry

    hpw would i draw a lewis structure for a molecule with 3.5 bonds for example NO2???

    asked on April 20, 2009
  58. chemistry

    Why are all diatomic molecules diatomic molecules linear, regardless of the number of valence electron pairs on the atom? i don't understand this question what is meant by linear?

    asked on April 8, 2009
  59. chemistry

    okay we are drawing bonds and i was wondering how i am supposed to know if you can make a double or triple bond for example for NH2OH why cant i make the bond between N and O triple instead of leaving lone pairs.. thanks

    asked on April 8, 2009
  60. math

    Define variables and write a system of equations for each situation. Solve using substitution. Suppose you are thinking about buying one of two cars. Car A will cost $17,655. Youn can expect to pay an average of $1230 per year for fuel, maintenance, and

    asked on April 2, 2009
  61. Social Studies

    Give two reasons for the new interest in leisure activities in the 1920s. i already know one: rising wages and labor-saving appliances gave families more money and more time in which to spend it.what else?

    asked on April 1, 2009
  62. Social Studies

    what's one good and bad effect of Prohibition?

    asked on April 1, 2009
  63. Science

    what does the geologic time scale indicate about the change in life-forms over time?

    asked on March 30, 2009
  64. Science

    how did geologists determine the divisions of the geologic time scale?

    asked on March 30, 2009
  65. chemistryy

    Most window cleaners are aqueous solutions of ammonia. A 9.00 mL sample of a particular window cleaner requires 42.95 mL of 0.0508 M HCl for its titration. What is the molarity of ammonia in the window cleaner? i am completely lost i cant even find the

    asked on March 26, 2009
  66. CHEMISTRY HELP

    NH3 + HCl --> can someone please finish that?? is it 2H2 + N2 + Cl or something? if so how would i balance it?

    asked on March 26, 2009
  67. chemistry

    Calculate the hydrogen ion concentration and the pH of each of the following solutions of strong acids. (a) 0.00010 M HCl if you could just explain how to do this that would be great! thanks

    asked on March 23, 2009
  68. DRBOB

    help below please

    asked on March 19, 2009
  69. chemistry

    does normality measure concentration of solutions??

    asked on March 16, 2009
  70. chemistry

    for my test i have to be able to Be able to determine the final molarity of a mixture of two solutions my teacher said the formula was m1v1 = m2v2/m1+v2 or something like that is that right??

    asked on March 16, 2009
  71. chemistry

    what are the different types of solutions?? is it saturated nonsaturated and supersaturated?

    asked on March 16, 2009
  72. chemistry HELP DRBOB

    Calculate the sodium ion concentration when 80.0 mL of 4.5 M sodium carbonate is added to 30.0 mL of 1.0 M sodium bicarbonate. how do i solve this I don't really know where to begin.. is there a formula for finding concentration because we don't learn this

    asked on March 10, 2009
  73. chemistry

    What volume of .101 M HNO3 is required to neutralize each of the following solutions? there are four and i got them all right but this one... 51.1 mL of .127 M NH3 i got 193 mL can someone please help???

    asked on March 10, 2009
  74. chemistry

    If the volume of solute is 6 ml and the volume of the solution is 300 ml, what is the solute's percent by volume? is it solute/solution so % = 6/300 so then would it be % = .02 would i change it to 2%???

    asked on March 8, 2009
  75. CHEMISTRY

    How much water should be added to 45.0 mL of 0.225 M HCl to dilute the solution to 0.155 M? i did .225M x .045L / .155M = 65mL so wouldnt 20 mL be added?

    asked on March 4, 2009
  76. chemistry

    How much of each starting material would you use to prepare 2.00 L of each of the following solutions? 0.240 M NaOH from 1.00 M NaOH stock solution what do i do with the .100 M and .240 M??

    asked on March 4, 2009
  77. chemistry

    What is the molarity of a solution when 3L of a 4M solution is mixed with 3L of a 6M solution?

    asked on March 3, 2009
  78. chemistry

    How would you prepare 250.0 ml of a 0.6 M aluminum sulfate solution

    asked on March 2, 2009
  79. chemistry

    How much water should be added to 55.0 mL of 0.201 M HCl to dilute the solution to 0.155 M? i used M1V1 = M2V2 and i got 71.3mL its wrong so im confused

    asked on March 2, 2009
  80. Chemistry Web Quest

    How do you recover the dissolved solid in a solution?

    asked on February 13, 2009
  81. chem

    how do you prepare a solution using the proper lab equipment(both from dry solid and a stock solution) i researched it but all i found was the definition for stock solution any help please!!

    asked on February 12, 2009
  82. chemistry -IMPORTANT-

    we have to make an instrctinal packet showin relationships between moles and concentration. i cant find the following 1)how is the number of moles dissolved in a set amount of solvent related to the molarity? 2)how to determine the amount of solvent in

    asked on February 12, 2009
  83. unit

    is cm^3 and cc and mL all the same??

    asked on February 11, 2009
  84. chemistry

    we did a lab where we mixed an iron nail with cupric chloride to find the reaction is this the balanced equation... Fe + CuCl2 --> FeCl2 + Cu or would Fe and Cl bond different??

    asked on February 10, 2009
  85. chemistry

    Solutions that have large amounts of solute are___ solutions that have small amounts of solute are ___

    asked on February 8, 2009
  86. math

    function rule for tis points- 1 2 3 4 lines- 0 1 3 6 its similar to an earlir one i posted but i still don't quite understand thanks

    asked on February 2, 2009
  87. math

    what is the function rule for this figure sides- 3 4 5 6 7 diagonals- 0 2 5 9 15

    asked on February 2, 2009
  88. chemistry

    #2) Consider the preciditation reaction of a solution containing 3.50 grams of sodium phosphate mixed with a solution containing 6.40 grams of barium nitrate. How many grams of Barium phosphate can form? Ba(NO3 )2 + Na3 PO4 yields Ba3 (PO 4 )2 + NaNO3 #2b)

    asked on January 29, 2009
  89. chemistry

    im having trouble balancing this. I tried it but everything just ends up being uneven Ba(OH)2 * 8H2O + NH4SCN --> Ba(SCN)2 + H2O + NH3

    asked on January 27, 2009
  90. chemistry

    When ammonia gas is burned in oxygen the products formed are water and nitrogen monoxide gas. Write the balanced equation showing this reaction NH4 + O2 --> H2O + NO i am stuck balancing this

    asked on January 23, 2009
  91. all teachers

    is dr bob on

    asked on January 23, 2009
  92. chemistry natalie

    can anyone tell me if natalie is on

    asked on January 22, 2009
  93. for anyone

    is there any way to tell if a teacher is currently 'on' and answering other question

    asked on January 21, 2009
  94. chemistry

    Ca + Br2 --> CaBr2 its synthesis and the reason the reaction happens is stable electron configuration but i don't understand why.

    asked on January 21, 2009
  95. chemistry

    3BaCl + 2Na3PO4 --> Ba3(Po4)2 +^NaCl is Ba3(PO4)2 the ppt. because Cl salts are soluble so it will dissolve?

    asked on January 21, 2009
  96. chemistry

    i did a lab and found that of the products two gases were formed H2 and H2CO3 the question is... What are the tests that will verify the identity of these gases? what is this asking?

    asked on January 20, 2009
  97. chemistry

    NaCl + CuSO4 to write the product would i just do double replacement to get Na2SO4 + CuCl2 so the whole thing would be 2NaCl + CuSO4 --> Na2SO4 + CuCl2

    asked on January 20, 2009
  98. chemistry

    predict the identity of the precipitate that forms. calcium nitrate, Ca(NO3)2, and sodium chloride , NaCl why does the answer come out as no reaction? couldnt it form to be CaCl2 or NaNO3 i thought it had something to do with the fact that Na and NO3 are

    asked on January 13, 2009
  99. chemistry

    What does it mean to say that the ions of an electrolyte behave independently of one another when the electrolyte is dissolved in water? is it something about the compound splitting?

    asked on January 13, 2009
  100. math

    1/2|6y-9| +5 is < or = 2 i solved it and got two fractions but the answer is 0 can anyone explain? btw this is absolute value inequality.

    asked on January 8, 2009

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