chemistry! URGENT

61,546 results, page 2


    Can ANYONE please help me by going to either the very bottom of this page or the top of the next and click on "English-URGENT-HELP NEEDED!"? I really need some help on that one and I'm afraid no one will find it and I'll have to keep posting it over and over. THANK-YOU ...
  2. Venus (URGENT)

    Okay, i'm doing this Planetary tourism brochure assignment. I have to make a brochure about the planet. What are some special natural features and attractions on Venus. (special moutains, craters, canyons, surface spots.) Be creative in your descriptions, don't list facts. How...

    Write a balanced equation for the following reduction-oxidation reaction. SO3(2-) + MnO4(-) --- SO4(2–) + Mn(2+) can someone help me step by step??
  4. chemistry urgent

    given the reaction: 2 Al + 3 H2SO4 -> Al2(SO4)3 + 3 H2 what volume of H2 gas measured at STP will be produced from 5.4 grams of AL reacting with an excess of H2SO4?
  5. Chemistry Urgent Help Please!

    If caffeine is soluble in hot benzene but insoluble in hot petroleum ether, how could you use this information to design a crystallization procedure?
  6. Chemistry URGENT

    I need help balancing a equation for the combustion of cellulose in oxygen to produce carbon dioxide and water vapor. C6H10O5 = 6CO +5H2O I know this is not correct but I don't know what else to do to get this to balance. Thanking you in advance.
  7. chemistry urgent

    if 100 g of iron were reacted with 100 g of oxygen according to the reaction below, the maximum yield in grams of Fe2O3 would be: Dr. Bob. Please help.
  8. Chemistry Urgent please help! Test tomorrow

    if you have a mixture of sodium chloride and sodium bromide, could you use its conductance to determine the concentration of each solution? explain
  9. chemistry urgent!

    what is the net ionic for these following balanced equations: 2(NH4)3PO4(aq) + 3Ba(OH)2(aq) -> Ba(PO4)2(s) + 6H2O(l) + 6NH3(g) 2HNO3(aq) + K2CO3(aq) -> H2O(l) + CO2(g) +2KNO3 NaF(aq) + HCl(aq) -> NaCl(aq) + HF(aq)

    a sample of oxygen that occupies 1.00 x 10^6mL at 575mmHg is subjected to a pressure of 1025atm. what will the final volume of the sample be if the temperature is held constant? how do uu set up the equation

  12. Socials Studies *URGENT*

    Research Territory, Food, Shelter, Transportation and Effect of European contact for Ojibwa, Assiniboin, Cree, Chipewyan, Inuit. Please help this is URGENT. I can't seem to find "Effects of European contact" for any of the groups. Although I don't quite understand what it ...
  13. chemistry first yera

    A 0.4 g sample of monobasic acid requires 16cm3 of 0.1 mol per dm3 of NaOH for complete neutralization . what is the relative mass of the acid?? Plz ans me urgent

    Which answer explains why there isn’t a hyphen between well and behaved in the following sentence? The students were so well behaved that Ms. Irvin dismissed them early. (1 point) The words well and behaved don’t end in -ly. The words well and behaved are on the same line...
  15. chemistry PLEASE HELP URGENT

    Calculate the amount concentration of the cations in the following solutions: A) 0.5 mol/L sodium carbonate B) 0.2 mol/L ammonium sulfite C) 1.5 mol/L iron 3 sulfate
  16. Chemistry! Urgent!!

    0.080 m FeCl3 find the boiling point it. so i did ( 0.080)(.51)(4)+100 and i got 100.16 whyy is that wrong?
  17. chemistry. urgent!

    where woudl i put the propyl in 2-propyl benzoate? i thought the propyl had to be attactched to the O and wouldnt that just be 1-propyl not 2?
  18. chemistry! URGENT!!!

    A gaseous mixture of O2 and N2 contains 30.8 % nitrogen by mass. What is the partial pressure of oxygen in the mixture if the total pressure is 365 mmHg?
  19. Chemistry urgent please

    How much mL of dilute nitric acid is needed to add in control solution in chloride limit test in sodium hydroxide sample???can u please give me Answer urgently??
  20. chemistry

    URGENT!!! what is the chemical reaction of hyrodgen peroxide + NH3 ... The chemical formula and written formula!!
  21. Chemistry *Urgent*

    The maximum number of electrons that can occupy ONE f orbital is: A. 14 B. 6 C. 2 D. 18 E. 10 Wrong Points Earned: 0/2 Your Response: A Seriously can't an f orbital hold 14 electrons?
  22. Chemistry(Urgent, please answer)

    If you are given the slope and y intercept how do you find the rate constant of a chemical equation??? Would I multiply the slope and the y intercept???
  23. Chemistry(URGENT!)

    determine whether the following salts will form acidic, neutral or basic solutions in water. Na2HPO4 CaNO2 NH4CH3COO Al2SO4 NaF Please, i need the answer to this question within 2 hours of when i post this!
  24. Chemistry(Urgent, please help)

    I have to calculate the concentration of I2 produced (# of moles of I2 produced / L) based on the stoichiometric ratio in the following equation. 2S2O3^2- + I2 -> 2I^- + S4O6^2- Would the # produced be 2 for I2. I am not sure what to use for L?
  25. chemistry (urgent)

    can you tell me how the beta-plus decay process may be understood (i) at the level of individual nucleons and (ii) at the level of quarks, by writing a decay reaction in each case.
  26. Chemistry

    Zinc coats Iron and prevents it from rusting. However Iron cannot be used to coat zinc and prevent it from corroding.Explain this phenomenon.HELP PLEASE URGENT!!
  27. chemistry urgent

    what volume in liters of gaseous hydrogen chloride can be prepared from 40.0 liters of hydrogen with an exces of chlorine? all volumes are measured at STP: H + Cl -> HCl
  28. Chemistry VERY URGENT PLEASE

    What does the chemical formula, MgSO4 * 7H2O, become when the hydrated is heated? I got so far is MSO4 * 7H2O + Heat ---> MgSO4 + H + O
  29. chemistry urgent

    if 500 ml of HCl solution is needed to react with 2.43 g of Mg, what is the molarity of the HCl solution?

    HNO3 with pH 3 is mixed with 2 L KOH with pH 12. assuming volumes are additive what is the pH of the final solution? I have absolutely no idea how to do this. I do know the answer, though. I have a test tomorrow and I would really appreciate it if someone could help!!!!

    24cm^3 of a mixture of methane and ethane were exploded with 90cm^3 of oxygen. After cooling to RTP the volume of gases was noted and it decreased by 32cm^3 when treated with KOH. Calculate the composition of the mixture.

    Which of the following pairs of compounds will give a precipitate in a diluted solution? Question 4 options: A) Cu(NO3)2 and Na2CO3 B) KNO3 and NaCl C) MgCl2 and Ba(NO3)2 D) NH4Cl and Al2(SO4)3 ALL OF THEM ARE SOLUBLE? WHAT DO I DO?
  33. URGENT chemistry

    Mulitple choice What is the concentration of H^+ in solution given the [OH^-]= 1.32x10^-4 a)7.58x10^-11M b)1.32x10^-11M C)1.0x10^14M d)not enough information E)none of the above

    An electron transition in a single H-atom from n=3 to n=2 results in the release of a single photon. What is the wavelength of this photon in nanometers? NEED ANSWER CUZ MINE ISNT WORKING
  35. Social Studies (URGENT)

    Pleae help. It's urgent! 10. Why did many Native people start adapting to Victorian society? a.) Was this the only way that things could have gone between the Natives and the colonists? Explain your response. b.) Why didn't the settlers adapt to Native customs and traditions? ...
  36. chemistry urgent

    I think I balanced these equation right please check and let me know. i am suppose to complete and balance the equations representing the reactions. NaHCO3 (s) + HCL (aq) >>>> NaCl + 2CO+H2O CaCo3 (s) + HCL (aq)>>> CaCl + CO3H Thanks
  37. Chemistry URGENT/DR BOB

    I have a couple of unfinished experiments i need help with as well. If you can help me. Thanking you in advance. If I tested the ph of NaOH and its H+ was 12.2 how would I express this in a power of 10? I really have no clue. Need help.

    How to draw line graph for showing changes in test tubes while showing that exhaled air contains more carbon dioxide than inhaled air
  39. Chemistry (urgent!)

    A titration of 15.0 cm3 of household ammonia, NH3, required 38.57 cm3 of 0.78M HCl. Calculate the molarity of the ammonia. Please show steps so that I may unders tand how solve this. Thank you
  40. Chemistry

    In an IR spectrum at wavelength = 1454cm-1 its where a CH2 group is present but then when it come to writing it down do I write v(CH) bend or v(CH2) bend please if your unsure dont answer me its urgent thankyou
  41. Chemistry(Urgent, please check)

    For C4H10O a constitutional isomer can be written as C-C-C-C-O-H with hydrogens also coming off of the 4 carbons. I know that this is an alcohol. I need to know if there are stereoisomers for this other than conformers. I think that there are stereoisomers because you can just...
  42. chemistry URGENT!

    each tablespoon of the liquid contains 95mg of aluminum hydroxide and 412mg of magnesium many moles of hydronium ion can be neutralized by one tablespoon of it?al(oh)3 =78g/mol ;mgCo3 =84.3 g/mol
  43. chemistry-URGENT

    Hydrazine is used as a rocket fuel. When 1.50 g of hydrazine, N2H4, was burned in a bomb calorimeter, temperature increased from 23.57 °C to 28.84 °C. The heat capacity of the calorimeter was 5.510 kJ/°C. Determine the enthalpy of combustion of octane.
  44. Chemistry

    2 NO + O2 --> 2 NO2 The reaction rate is increased five­fold when the temperature is  increased from 1400 K to 1500 K. What is the activation energy for the reaction?  I have no idea how to do this and would greatly appreciate some urgent help!
  45. Chemistry- urgent!

    Perform the following operations and express the results in the correct number of significant digits or decimal places. Express all results in scientific notation. Please help me I'm so confused on how to do this!! 15. (1.71 x 10^6)(6.73 x 10^-8)/2.25 x 10 20. (533)(24) 21. (1...
  46. Chemistry URGENT

    If a student starts with 615g of Co(NO3)2 and obtains a 57.3% yield of CoS, what mass of CoS is isolated? Co(NO3)2 + K2S ---> CoS + 2KNO
  47. character education

    What is the difference between proactive and reactive? proactive acts upon what is important; reactive acts only on what is urgent proactive does only what is convenient, reactive does what is urgent proactive changes one's circumstances; reactive adapts to one's circumst B?
  48. chemistry/physics Urgent!!

    how do i calculate the substrate concentration needed relative to Km to produce a rate relative to Vmax which is 0.1 x Vmax ?? I think i need to manipulate the michaelis menton eq but when i do it im left with [s] in the amount please help lib
  49. Chemistry urgent

    C6H14 + Cl2 in UV light Below are 5 products, say which one cannot be a product, prove this by showing how each of the other products were formed from the equation above. 1-chlorohexane 2-chlorohexane 2,2-dichlorohexane dodecane hex-1-ene
  50. Chemistry URGENT/DR BOB

    Hello DR. BOB, the correct value in the problem posted at 1:17pm regarding Student A and Student B accuracy and random error is the: MEAN of 2.63 g/mL. Could you take a look back at that post and let me know if i answered 2 and 3 correctly.

    carbon dioxide is moderately soluble in cold water but is completely boiled out if the water is boiled.Solubility increases rapidly with pressure. How is the above phenomenon used in the production of aerated drinks?
  52. chemistry

    can anyone tell me about the molecular orbital energy order in energy level diagrams????its molecular n not atomic..... plz tell me its very urgent!!!!
  53. Chemistry! URGENT!

    Calculate the solubility, in molL―1, of lead sulfate, PbSO4, in a 0.0185 M solution of sodium sulfate, Na2SO4 . Ksp (PbSO4) = 1.6 x 10―8 I get 8 x 10^-9...but that is not right! Thanks!
  54. Chemistry- urgent help needed

    How do I prepare 40% v/v from 95% ethanol? When we say 95% ethanol, do we usually mean 95% w/w ethanol unless otherwise stated? Please show me the calculation steps to prepare 40% v/v from 95% w/w ethanol. Thanks.
  55. URGENT Chemistry Question!

    This might be a silly question, but... Is 6-8 on the pH scale considered neutral? If so, 6.23 pH is neutral and 8.78 should be considered basic. Is this correct?
  56. chemistry

    URGENT!!! How many grams of sodium benzoate (NaC6H5CO2) must be added to 500 mL of 0.15 M benzoic acid (HC6H5CO2) to make a buffer solution with pH of 5.0? Assume no volume change upon sodium benzoate dissolution. Ka = 6.46 x 10-5 How would I go about this question?
  57. Chemistry URGENT!

    If the reaction of 0.500 grams of aluminum metal with excess aqueous HCl releases 9.72 kJ of heat, what is the ΔH value for the reaction? 2 Al(s) + 6 HCl(aq) → 2 AlCl3(aq) + 3 H2(g) All I have is: .500gAl*(1 mol Al/26.98gAl) Please and thank you so much!
  58. Statistics PLZ HELP Urgent!!!!

    PLZ Help me with the following questions! very urgent! The marketing department of a company would like to introduce 12 monthly special products in the coming 12 months. If these monthly special products are selected randomly from 24 products, find the probability that two ...
  59. chemistry urgent

    calculate the number of joules of heat required to change 85.0 grams of water at 25oC to steam at 10oC (heat of vaporization of water = 2260 j/g and specific heat of water = 4.18 j/g oC)
  60. Chemistry URGENT

    I need help understanding oxidation I have a problem that states: The proper assignment of oxidation numbers to the elements in the compound LiAsO3 would be: I think the answer is +1 for Li, +3 for As and -2 for O. I think I am confusing oxidation with ionic charge. PLEASE HELP
  61. Chemistry

    How do you do the question: react 3.50 g of solid sodium metal with water to produce hydrogen gas and sodium hydroxide. If,at the end of the reaction there is 6.8 L of solution, what is the concentration of sodium hydroxide? This is realy quite urgent. I need to know for my ...
  62. urgent help chemistry!!

    2H2 +O2 ---> 2H20 A container at a o degrees celcius is filled with a mixture of oxygen and hydrogen. The fastest way to establish an equilibrium is.. 1. add more H2 2. do nothing, equilibrium will occur 3. increase the temperature 4. increase surface area. which is correct?
  63. Chemistry Very Urgent!!

    A 0.035 M solution of a weak acid (HA) has a pH of 4.88. What is the Ka of the acid? HA ==>H^+ + A^- Ka = (H^+)(A^-)/(HA) pH = -log(H^+) You know pH. Convert that to (H^+). (H^+)=(A^-) so plug those into the expression for Ka. (HA) = 0.035 M - (H^+). Plug that in. Calculate...
  64. Chemistry (URGENT)

    T=thickness, V=volume, A=area, m=mass D=density V=m/D Suppose T=V/A is a method used to find the thickness. How may this method be used in finding the size of molecules.? I really need help. Been thinking about it for awhile. Thanks in advance.
  65. CHEMISTRY LAB urgent assistance

    1 (A) This relation gives the dissociation constant of acetic acid (CH3COOH) Ka = [H3O+][CH3COO-]\[CH3COOH] Starting from this relationship show that pH = pKa + log [base]\[acid] urgently need assistance
  66. Chemistry

    Urgent! Considering the following equation. Na2Co3(s)+H3Po4(s)=>Na3Po4(s)+H2O(l)+CO2(g). a) what's the energy amount envolved in the reaction? b)what is the volum of the released gas? c)what the volum of the consumed phosphate acid, considering d=1,69g/ml? Really need to ...
  67. chemistry URGENT

    What is the total gas pressure in a sealed flask that contains oxygen at a partial pressure of 0.39 atm and water vapor at a partial pressure of 0.47 atm?
  68. URGENT Science question

    Justin wants to be the captain of an aircraft carrier when he gets out of school. Which subjects should Justin study to help him prepare for this career? biomedical science and meteorology oceanography and paleontology chemistry and biology physics and computer science*** Am I...
  69. Chemistry (urgent)

    1.Using Nerst, find the E of the cell for the dicromate redox system: A.under standard conditions. B.under neutral solutions instead of acid solutions. 2.Use Nerst and the hydrogen half equation to obtain an expression for pH.
  70. chemistry ( little urgent pls)

    For oxidation of iron 4Fe+3O2=2Fe2O3 the entropy change is -549.45JK^-1mol^-1 at 298K. Though it has negative entropy change in the reaction is spotaneous.why? (Delta r H theta ∆rH°=-1648×10^3 J ml^-1. Is it because ∆G is negative????

    A uniform ladder of length 20.0m and weight 750 N is propped up against a smooth vertical wall with its lower end on a rough horizontal surface. The coefficient of friction between the ladder and this horizontal surface is 0.40. (b) Work out and add the numerical values of ...

    1) the element Q has the electronic configuration 1S2, 2S2, 2p6, 3s2, 3p6, 4s2 3d10, 4p1. Write the atomic #. Q exist as 69Q and 71Q. What is the significance of the 2 #'s. What does it mean. B) find the atomic mass if 69Q is 60% anf 71Q is 40%
  73. Chemistry Urgent Help

    if 4.55 g of sodium sulphide and 15.0 g of bismuth nitrate are dissolved in separate beakers of water which are then poured togehter, what is the maximum mass of bismuth sulphide an insoulble compound that could precipitate? Which reactant was the limitting reactant? Na2S + Bi...
  74. high level chemistry

    can anyone tell me about the molecular orbital energy order in energy level diagrams????its molecular n not atomic..... plz tell me its very urgent!!!!
  75. urgent urgent algebra / precalculas

    For # 1, im getting stuck on this problem i don't understand this 1.4 = e ^ (0.03k) Now take the natural logarithm of both sides to solve for , ln 1.4 = ln e ^ (0.03k) ln 1.4 = 0.03k * ln e Recall that ln e = 1. ln 1.4 = 0.03 k Solve for k. Then try part b. For # 2, y = 3 + e...

    30cm^3 of a mixture of methane and ethane were mixed with 100cm^3 of oxygen at ordinary temperature and pressure and exploded. After cooling the residual gases occupied 61.5cm^3. Find the percentage by volume of each gas in the mixture, methane (CH4) and ethane(C2H6).
  77. Chemistry (URGENT)

    Suppose a reaction involved a finely ground powder reacting with a concentrated acid. Suggest three methods of decreasing the reaction rate. 1. By placing the reactants in cold water. 2. ? 3. ? Can someone please help? I can't think of what else I can do to slow down the ...
  78. Chemistry (urgent)

    Suppose a reaction involved a finely ground powder reacting with a concentrated acid. Suggest three methods of decreasing the reaction rate. 1. By placing the reactants in cold water. 2. ? 3. ? Can someone please help? I can't think of what else I can do to slow down the ...
  79. chemistry-URGENT!!

    A sample of ammonina gas at 65.5 degrees celsius and 524 torr has avolume of 15.31 L. What is it's volume at -15.8 degrees celsius and its pressure is 524 torr?
  80. Urgent chemistry

    Given the following reaction: 3 H2(g) + N2(g) <- -> 2NH3(g) + heat If the following changes were to occur what direction shift will it have (left or right) And what will be the reason of the shift Changes/Stress on system: Decreasing the pressure Adding heat Removing N2
  81. organic chemistry -urgent

    Which samples were pure and which were mixtures? How many different component compounds are in each mixture and what colour are they? Are there two different coloured ink samples that contain a common component? ( ALL THESE QUESTIONS ARE RELATED TO THE COLOUR CHROMOTAGRAPHY ...
  82. Chemistry(Urgent, please help,thank you)

    After performing a freezing point depression experiment I had to find the molecular weight of glycol. Now I have to answer the question what value did I assume "i" to equal and why did I make this assumption. My teacher told us the value of i to use for this was 1. I am not ...
  83. Chemistry (College) URGENT

    1.6g of an unknown monoprotic acid (HA) required 5.79 mL of a 0.35 M NaOH solution to reach the equivalence point. Determine the molar mass of the acid and given that the pH at the half way point to the equivalent point is 3.86. Calculate the Ka of the unknown acid.
  84. Chemistry- DrBob222 Urgent Please help

    Name these: a) CH2=CH-CH=CH2 b) CH3-CH=CH-C(TRIPLE BOND)CH c) CH3-CH2-CH2-CH(Cl)-CH(Br)-CH3
  85. chemistry

    Urgent. The melting point of pure acetylsalicylic acid is 135 degrees celsius. Comment on the purity of your product based on its melting point range. My melting point range was 105-115. I do not even know where to start for this question. Could you please help?
  86. Urgent Chemistry question!

    How do i combine 2 half ionic equations into an overall equation?? 4OHˉ → 2H2O + O2 + 4e 2H+ + 2e → H2 *The "H+" is the hydrogen ion The correct overall equation is 2H2O → 2H2 + O2 How do i get that???
  87. 11th grade [URGENT]

    Help with my research essay!? I have this assignment I have to do and its a research essay. I was wondering if this was a good topic (not too broad or not too specific) for my essay: Behind fast food, or like does fast food take effect on obesity? I've chosen to do something ...
  88. Chemistry (URGENT)

    What property of paradichlorobenzene may convince you that it is an ingredient in mothballs? Please help. I have no idea. I did search up mothballs and (PDB) is an ingredient but I don't know what property of PDB convinces that it's an ingredient. Any help greatly appreciated.
  89. chemistry-urgent

    Silver nitrate is added to a solution and precipitate forms. This precipitate dissolves when concentrated ammonia is added. What anion was present in the original solution? I don't know how to answer this. Also can someone please explain how to identify a cation and anion in a...
  90. algebra

    6x+8y=24, 8y-6x=2 what is x and what is y? urgent! thanks:)
  91. math urgent!!!!!!!!

  92. algebra URGENT HELP

    A)p(x)= x(x+2)(x-4) b)p(x)=(x+2)^3(x-1)
  93. Maths urgent

  94. Urgent Chemistry!!

    1 mol of an ideal gas expands under isothermal conditions (T=298.15K). The initial pressure and volume is 2.00 atm and 1.00L respectively, and the final pressure is 1.00 atm. Find the expansion work. The answer is w = -101.325 J. I am unsure how to get this answer. Can someone...

    A hot-air balloon has a volume of 970 L at 28 degrees C . To what temperature must it be heated to raise its volume to 1200 L , assuming the pressure remains constant? so it would be 970L/28degreesC=1200L/x? I did that and I got 34.6 degrees C and when i put it into my answer ...
  96. Algebra 2 URGENT

    Simplify: 4s^-2-(4t)^-2
  97. Algebra 2 URGENT

    Simplify: (1)/(z-4)-(1)/z+4
  98. Algebra 2 URGENT

    Simplify: (x)/(x-1)-(1)/(x+1)
  99. Algebra 2 URGENT

    Simplify: (1)/u^2-(2u)/(1)/(u^2-4)
  100. Algebra 2 URGENT

    Simplify: (1)/(t^2+t)+(1)/(t^2-t)
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