chemistry! URGENT

61,637 results, page 29

  1. Chemistry

    Hi I was hoping to get some help on this. It's review for my chemistry text on Monday and I would be grateful if someone could help me out. My teacher has been out for two weeks but we still have to know this material. 1. The following data was collected for the reaction ...
  2. chemistry

    Posted by Jenni on Monday, December 13, 2010 at 3:32pm. Determine the molarity of nitrate ions in a solution prepared by mixing 25.0 mL of 0.50 M Fe(NO3)3 and 35.0 mL of 1.00 M Mg(NO3)2 Please explain fully do not know where to start? chemistry - DrBob222, Monday, December 13...
  3. Chemistry

    DrBob222, I don't know how to solve this problem either. And yes, this is the question for this problem. I even double check it. Please help. Chloroform (CHCL3) has a normal boiling point of 61 'C and an enthalpy of vaporization of 29.24 kJ/mol. What is the value of delta Gvap...
  4. Chemistry

    Indicate how each of the following would affect the value of the absorbance (too high, too low, or not effect) of the indicated solution. I really need help. I do not understand these questions! This is from a chemistry activity to determine the unknown concentration of an ...
  5. Science (Chemistry)

    I did not understand the lesson today in my Chemistry I honors class. We went over the Law of Conservation of Mass for roughly 15 minutes and he gave us this worksheet. Could someone please display how to do this, I'll pull a problem from the worksheet. When 9.56g of Copper ...
  6. statistics

    Leslie took two midterm exams and earned the following scores: 82 on the chemistry exam (class distribution: μ = 75, σ = 6.25) and 63 on the physics exam (class distribution: μ = 59, σ = 3.57). Rounding to two decimal points, on which exam should Leslie get...
  7. chemistry

    High-pressure liquid chromatography (HPLC) is a method used in chemistry and biochemistry to purify chemical substances. The pressures used in this procedure range from around 500 kilopascals (500,000 Pa ) to about 60,000 kPa (60,000,000 Pa ). It is often convenient to know ...
  8. chemistry??

    Oxidising and reduction- Chemistry? Oxidation and reduction can be described as the loss and/or gain of electrons from an ion or atom (species) in a chemical reaction. For thefollowing aqueous reaction, select the species that is oxidized and similarly the one that is reduced...
  9. Chemistry

    High-pressure liquid chromatography (HPLC) is a method used in chemistry and biochemistry to purify chemical substances. The pressures used in this procedure range from around 500 kilopascals (500,000 Pa ) to about 60,000 kPa (60,000,000 Pa ). It is often convenient to know ...
  10. Chemistry

    In chemistry lab we did an experiment trying to find the empirical formula of an oxide and tin. The question is "suppose some of the oxide splattered out of the crucible. How would this affect your calculated ratio of the number of moles of oxygen to the number of moles of tin...
  11. chemistry

    I'm having trouble naming this organic chemistry compound. (I'm not sure how to include a picture in this, so I'll try my best to explain it in words and attempt to type it out) The full formula is C9H16. It's an alkyne and the longest carbon chain is 5 carbons long, so I know...
  12. Chemistry

    Income tax for some states is computed by taking 3% of the excess income over $3,000 plus 1% of the first $3,000. How much tax is charged on a income of $12,000? 12,000 1 percent on first 3000 3 percent of (12,000 - 3000) I'm trying to figure the relationship between income ...
  13. Chem

    if the pressure was increased in this reaction : 2NO(g)+ O2 =====> 2NO2 <==== wouldnt the product side be favored? Please tell me if I'm right or wrong There are three volumes on the left, two on the right. If pressure is increased, the reaction to the right is favored. ...
  14. Science help! URGENT. Check answers

    1. True or False: If the net force of an object is 0 N, the forces are considered unbalanced. (True) 2. Which of the following forces causes a feather to fall slower than a blowing ball? gravity ← rolling friction sliding friction air resistance 3. A small fish in the ...
  15. Chemistry

    H6P7: Young's Modulus Rank the following 3 classes of materials in order of increasing typical Young's Modulus: metals such as copper, plastics such as HDPE (high density polyethelene), and ceramics such as alumina (Al2O3). Do not look up the values of Young's Modulus, instead...
  16. Chemistry

    I did a lab for Organic Chemistry I did a simple distillation for an unknown and found that it boiled at 76 degrees. I also found out that the unknown was ethanol since we knew what the 4 possibilities were and mine was closest to ethanol. I also did a fractional distillation ...
  17. Chemistry

    The term mole is used in chemistry to define an amount of a substance. For example, a mole of glucose, blood sugar, weighs 180.16 grams. A common concentration unit for solutions is moles of substance per liter of solution. We abbreviate this with the symbol M. For example, 0....
  18. chemistry

    3.) One method used in the eighteen century to generate hydrogen was to pass steam through red-hot steel tubes. The following reaction takes place: 3Fe(s)+4H20(g)--->Fe3O4(s)+4H2(g) 1. What volume of hydrogen at STP can be produced by the reaction of 6.28 g of iron? 2. What...
  19. chemistry

    The "Chemistry in Focus" segment A Magnetic Moment discusses the ability to levitate a frog in a magnetic field because electrons, when sensing a strong magnetic field, respond by opposing it. This is called diamagnetism. Atoms that are diamagnetic have all paired electrons. ...
  20. Chemistry

    In winemaking, the sugars in grapes undergo fermentation by yeast to yield CH3CH2OH and CO2. During cellular respiration, sugar and enthanol are "burned" to water vapor andCO2. A) Using C6H12O6 for sugar, calculate ÄH of fermentation and of respiration(combustion). B) Write a...
  21. Spanish (URGENT)

    Habia una vez hay un conejo pequeno. El no estaba contento. Queria mirar como les otros animales. Cuando él vio Mr. Bushy Tail, la ardilla, él quise una cola que se parecio las ardillas. Entonces, él vio Mr. Porcupine y el quise (quills). Entonces él pasó Mrs. PuddleDuck ...
  22. Chemistry(Please respond)

    A study of the system, H2(g) + I2(g) == 2 HI(g), was carried out. Kc = 54.9 at 699.0 K (Kelvin) for this reaction. A system was charged with 2.50 moles of HI in a 5.00 liter vessel as the only component initially. The system was brought up to 699.0 K and allowed to reach ...
  23. chemistry ................chemistry

    what is the color a mixture of sodium and potassium compounds?? What is the color a mixture of sodium and potassium compounds (use the cobalt glass)??
  24. Chemistry AP

    Calculate the pH of a 0.44 M aqueous solution of NH4Cl. Kb = 1.8 × 10−5 . I've tried used the Ka=Kw/Kb equation then used the resulting 5.5e-10 in Kw=([H+][Cl-])/[NH4Cl] , using that to get the [H+], but it isn't correct and I don't know what else to do. Chemistry AP - ...
  25. chemistry Dr BOB

    is this right? C2H6O + 3O2 = 2CO2 + 3H2O In winemaking, the sugars in grapes undergo fermentation by yeast to yield CH3CH2OH and CO2. During cellular respiration, sugar and enthanol are "burned" to water vapor andCO2. Write a combustion reaction for ethanol. I need help with ...
  26. chemistry

    1. A website promoting the use of alternative energy vehicles and hybrid technologies claims that, \"A typical automobile in the USA uses about 40 gallons of gasoline every month, producing about 750 lbs of carbon dioxide.\" To determine the truth of this statement, calculate ...
  27. MARKETING

    Mr. Pennymarch, the advertising manager for Chemistry Today magazine, is responsible for selling advertising space in the magazine. The magazine deals primarily with chemical processing technology and is distributed solely by subscription. Major advertisers in the magazine are...
  28. Chemistry

    I am unsure how to write hypotheses for my experiments for pH, salinity using tirration(agno3), turbidity, conductivity of water samples. The teacher wants the hypothesis in this format Hypothesis format - If (relationship between independent variable and dependent variable) ...
  29. chemistry

    Online chemistry lab preparing standards help? I was told to prepare some standard for a chemistry lab and here where the instructions: Obtain a solution of known phosphate concentration. In this lab we will use (1.e-002M) potassium dihydrogen phosphate, KH2PO4. Note the ...
  30. Chemistry

    a) The element with the greatest density is osmium, which has a density of 22.6g/cm3. calculate the mass of 32.1 cm3 of osmium. Answer: 22.6g x 32.1 = 725.46 Did I have right answer? b) A team of students determined the density of a sample of wood to be 0.52g/cm3. A handbook ...
  31. chemistry

    I did a project for lab chemistry where my aim was to see which substance, from a selection of 4 chlorides, recrystallises from a solution to form the most crystals. The 4 chlorides were KCl, NaCl, MgCl2 and CaCl2. KCl and NaCl didn't form any crystals, they formed a saturated...
  32. Chemistry

    I did a project for lab chemistry where my aim was to see which substance, from a selection of 4 chlorides, recrystallises from a solution to form the most crystals. The 4 chlorides were KCl, NaCl, MgCl2 and CaCl2. KCl and NaCl didn't form any crystals, they formed a saturated...
  33. CHemistry

    I did a project for lab chemistry where my aim was to see which substance, from a selection of 4 chlorides, recrystallises from a solution to form the most crystals. The 4 chlorides were KCl, NaCl, MgCl2 and CaCl2. KCl and NaCl didn't form any crystals, they formed a saturated...
  34. Chemistry

    Ok i'm supposed to google these values for my teacher, but i can't get the answer im looking for...if you have them can you give them to me? Latice Energy for: Ammonium Nitrate and Calcium Chloride Hydration Energy for: Ammonium ion, Calcium Ion and Chloride ion Thanks I had ...
  35. Chemistry

    If you have 200 ml of a 0.1M solution of acetic acid (pka=4.75), 1. How many ml of a solution of 1.O M NaOH would you need to adjust the pH to 5.2? "Chemistry - DrBob222, Wednesday, June 29, 2011 at 8:41pm 200 mL x 0.1M = 20 mmoles. 1. ............HAc + OH^- ==> Ac^- H2O ...
  36. chemistry

    The letters CHEMISTRY were spray painted in blue paint on the snow. After a while the sun comes out and the snow under the blue paint melts while the snow around the letters do not. Why did the snow under (rather than around) the blue paint melt?
  37. chemistry

    Strychnine, C21H22N2)2(aq) is a weak base but a powerful poison. Calculate the pH of a 0.001 mol/L solution of strychnine. The Kb of strychnine is 1.0 x 10^-6 DrBob222, I am planning on obtaining a pHD in about nine years:P Can you give me some advice on how to be that 1% of ...
  38. Urgent!

    Project: Data Analysis The following chart lists the average low, average high, record low, and record high temperatures for the month of April in Denver, Colorado. Day Average Low Average High Record Low Record High April 1 32°F 58°F 6°F 78°F April 2 32°F 58°F -3°F 79...
  39. chemistry

    I wanted to check my True and False Chemistry HW. I am not 100% they are correct. 1.the number of neutrons in an atom is reffered to as its atomic number False 2.the periodic table is arranged by increasing atomic number True 3.atomic number is equal to the number of electrons...
  40. chemistry

    Hey guys please help me answer these chemistry questions.? 1. can a strong acid be diluted. explain in detail 2. can a weak acid be diluted. explain in detail 3. how does your observation of sunlight change when you place two different concentrations of food colored solution ...
  41. Chemistry Equation(again!)

    Posted by chrissy on Saturday, January 6, 2007 at 1:23pm. In a lab expirement you add copper(II)nitrate to pure zinc. Write a balanced equation for this expirement and predict if a reaction will occur. For Further Reading Chemistry Equation - DrBob222, Saturday, January 6, ...
  42. Physics Urgent please help

    At low speeds (especially in liquids rather than gases), the drag force is proportional to the speed rather than it's square, i.e., F = -c_1*r*v , where c_1 is a constant. At time t = 0, a small ball of mass is projected into a liquid so that it initially has a horizontal ...
  43. Physics pls anyone can help me? its urgent

    At low speeds (especially in liquids rather than gases), the drag force is proportional to the speed rather than it's square, i.e., F = -c_1*r*v , where c_1 is a constant. At time t = 0, a small ball of mass is projected into a liquid so that it initially has a horizontal ...
  44. Chemistry

    A cup of teat containing 400g of liquid at 20 degrees celsius was heated. If 58.5 kj of heat was absorbed by the tea, what would the final temperature be? Assume that the specific heat of the tea is the same as that of water (4.18). I am not sure how to start this problem. ...
  45. Chemistry

    Can someone explain the molecular orbital theory and how to find the bond strength, bond length, and bond order? I'm also confused about the geometry of molecules & ions, like how to find the angles? (Like NH3 is 107 degrees, and H20 is 104.5 degrees, how do I find this when I...
  46. Chemistry Help! Thank you :)

    Assuming the final solution will be diluted to 1.00 , how much more should you add to achieve the desired pH? Information: Imagine that you are in chemistry lab and need to make 1.00 L of a solution with a pH of 2.80. You have in front of you: 100 ml of 7.00×10−2 M HCl...
  47. Chemistry (A level)

    I was given a Chemistry question on the titration of a strong base being added to a weak acid. The question was: "Calculate the pH in a titration when 10.0cm^3 of a 0.10moldm^-3 solution of NaOH is added to a 10.0cm^3 of 0.25moldm^-3 solution of ethanioc acid? (Ka = 1.76 x 10...
  48. maths

    In a class of 60 students,the number of students who passed biology is 6 more than the number who passed chemistry.Every student passed at least one of the two subjects.i.how many students passed biology ii.how many students passed chemistry iii.how many students passed only ...
  49. chemistry

    Hey guys please help me answer these chemistry questions.? 1. can a strong acid be diluted. explain in detail 2. can a weak acid be diluted. explain in detail 3. how does your observation of sunlight change when you place two different concentrations of food colored solution ...
  50. Chemistry

    Imagine that you are in chemistry lab and need to make 1.00 L of a solution with a pH of 2.70. You have in front of you * 100 mL of 6.00×10−2 M HCl, * 100 mL of 5.00×10−2 M NaOH, and plenty of distilled water. You start to add HCl to a beaker of water when ...
  51. Chemistry

    Hi Dr. Bob, this is a chemistry question. I don't know how to go about solving this problem: What is the pH of the solution created by combining 11.40 mL of the 0.10 M NaOH(aq)with 8.00 mL of the 0.10 M HC2H3O2(aq)? Here's what I have so far: (0.10M NaOH)(0.0114L)= 0.00114 mol...
  52. Chemistry

    For a chemistry lab the experiment was to carry out an acid-base titration to determine the exact concentration of a sodium hydroxide solution. Two trials were completed and the data collected was: mass of weighing paper, mass of weighing paper + KHP, mass of KHP, initial ...
  53. chemistry

    I don't think there is any benzene in Elmer's glue. In fact, I suspect finding something with benzene in it will be tough to do unless you have some OLD OLD bottles of something. Its a carcinogenic thing. If you are looking for something aromatic (meaning aromatic as in ...
  54. chemistry

    472 mL of H2 gas was collected over water when 1.256 g of Zn reacted with excess HCl. The atmospheric pressure during the experiment was 754 mm Hg and the temperature was 26 degrees C. A. Write the balanced chemical equation (I have this) Zn + HCl ---> ZnCl2 + H2 B. What is...
  55. Chemistry

    Hi, I'm trying to solve some chemistry problems, like the ones my teacher says will appear on our exams. The problem reads like this: What is the hydrogen conentration in a bleach sample that register 9.55 using a pH meter? My Attempt: Since this sample register a 9.55 on a pH...
  56. chemistry

    To what volume should you dilute 131 mL of an 8.20 M CuCl2 solution so that 49.0 mL of the diluted solution contains 4.53g CuCl2 ? Chemistry...Help!! - Dr Russ, Wednesday, December 8, 2010 at 4:43am Molar mass of CuCl2 is 134.5 g mol^-1 so solution needs to contain 4.53 g / ...
  57. chemistry -------------chemistry

    If a flame on the candle burns red , how does energy of that flame compare to that of the Bunsen burner flame ? and why ? ans:The Bunsen burner flame has higher temperature than candle’s flame . Because flame of candle emit red ,and red has the least energy in visible light.
  58. lab chemistry

    I did a project for lab chemistry where my aim was to see which substance, from a selection of 4 chlorides, recrystallises from a solution to form the most crystals. The 4 chlorides were KCl, NaCl, MgCl2 and CaCl2. KCl and NaCl didn't form any crystals, they formed a saturated...
  59. Urgent Language Arts~!

    10. In the following sentence, "Abraham Lincoln was a widely admired politician,” which statement is correct? (1 point) Add a hyphen between widely and admired. Add a hyphen between admired and politician. Add a hyphen between Lincoln and was. No hyphen is needed. 11. In ...
  60. Chemistry

    How do you calculate alkalinity in chemistry? Ex: List the values for total alkalinity for Sample A and Sample B A 104 drops of titrant (5.25mL) 3 drops of C20 H14 O4 B 81 drops of titrant (4.25mL) 3 drops od C20 H14 O4
  61. chemistry

    I need help with this question please help, I just don't understand it Fe3+ (aq), Ca2+ (aq) and Ba2+ are all present in the same solution. Fully describe a procedure whereby you could separate these ions from one another Mr Pursley posted this response, but I don't understand ...
  62. (19) Chemistry - Science (Dr. Bob222)

    Use the following information to answer this question: Cu+(aq) + e- → Cu(s) E° = 0.521V Cu2+ (aq) + e- → Cu+ (aq) E° = 0.153 V. Given these half cell reactions, an aqueous solution of Cu+ ion in the absence of O2(g) : A. will be thermodynamically stable B. will ...
  63. chemistry

    home / study / questions and answers / science / chemistry / a chemical engineer studying the properties of ... Question A chemical engineer studying the properties of fuels placed 1.760 g of a hydrocarbon in the bomb of a calorimeter and filled it with O2 gas The bomb was ...
  64. Chemistry(Please respond, thank you!)

    For the system CaO(s) + CO2(g) = CaCO3(s), I added 1.00 mol of CaO(s) to 1.00L of 0.500M CO2(g) at 200 oC. At equilibrium the [CO2] = 0.150M. What is the value of Kp for this reaction? Kp would = CaCO3/(CaO)(CO2) I do not know what to do with the 0.500M and 1.00mol. Chemistry(...
  65. literature

    plz to anyone who has finished the lit book with 7 tests answer back need help. with exms like pair of silk stockings, pauls case,goodman brown, call of the wild PLZZZZZZZ help me it has been 15yrs http://www.trainingner.com/does-anyone-have-the-answers-to-the-penn-foster-...
  66. Reposted: chemistry for Vic

    Can anyone suggest any good online/pdf exercises that will hone my skills in being able to determine the number of 1H and 13C signals in NMR spectroscopy? Answers would also be helpful. Perhaps these will help you get started. http://wwwchem.uwimona.edu.jm:1104/spectra/...
  67. chemistry- some help plzz totally lost on this one

    Imagine that you are in chemistry lab and need to make 1.00 L of a solution with a pH of 2.70. You have in front of you * 100 mL of 7.00×10−2 M HCl * 100 mL of 5.00×10−2 M NaOH, and * plenty of distilled water. You start to add HCl to a beaker of water when ...
  68. Spanish (URGENT)

    Can someone please check my work? Write a paragraph describing your party. La fiesta está en una grande mansión. Tiene seis cuartos, una recamára principal, tres (guest rooms), ocho baños, un comedor, un grande patio, una piscina interior, (and outside mini golf course) y...
  69. chemistry

    how many g/ml are there in 1M?
  70. AP Chemistry

    Which value of Ke
  71. chemistry

    what is (1.2*10^2)*(8.9*10^2)
  72. Chemistry

    X=\MX=\MX=\M What is this?
  73. chemistry

    3.5g
  74. Chemistry

    12.
  75. chemistry

    Thanks for the Help
  76. chemistry

    how do i d
  77. Chemistry

    What is pH
  78. Chemistry

    What does "Kc" mean?
  79. CHEMISTRY

    10-g what does it mean?
  80. Chemistry

    what is mm^2?
  81. Chemistry

    Can a pH be below 1?
  82. Chemistry

    1.0 x 10^5 mL=m^3
  83. Chemistry, pH

    What is the (OH-) when pH = 4.25
  84. chemistry

    How many \({\rm m}^{3}\) are in 7.40 \({rm cm}^{3}\)?
  85. Chemistry

    How
  86. Chemistry

    1.42 g/cm^2 to mg/mm^2
  87. chemistry

    when does 4+4=9
  88. chemistry

    thanks!
  89. chemistry

    in chemistry what is aq
  90. Chemistry

    How do you get the pH 13.68 into OH^-^?
  91. Chemistry

    Mg>Al>Ca>Rb>I
  92. Chemistry

    Did u think about it?
  93. chemistry

    what is the
  94. Chemistry

    Good morning. I need help solving 2 problems for chemistry. For #1 I need someone to check my work and tell me if I did it wrong and show me how and where I went wrong. And for #2 I need someone to help me figure out how to solve it and explain. 1. With the balanced equation ...
  95. CHemistry....Please help...DrBobb

    I posted this up yesterday: I have to use the equation : density= mass/ volume: But i don't know how to find out the volume using the edge length of the unit cell which is 5.88* 10^2 pm. CHemistry....Please help - DrBob222, Sunday, January 25, 2009 at 10:41pm If the edge ...
  96. chemistry

    what is the atomic number of ununhexium and the full symbol is this a transitional element that is a metal and what is its highest hydride and highest fluoride of ununhexium thanks What is known about Uuh can be found here. Look for element number 116. Go to www.webelelements....
  97. chemistry

    Table of enthalpy of solution for selected cesium salts Compound and ΔsolH kJ mol-1: - Cesium bromide: 25.98 - Cesium iodide: 33.35 - Cesium chloride: 17.78 - Cesium fluoride monohydrate: -10.46 - Cesium fluoride sesquihydrate (·1.5H2O): -5.44 Data taken from CRC ...
  98. chemistry help!

    I have a chemistry test tomorrow and I'm trying to study but none of these questions in the book make sense to me:( Help! 1. Commericially available concentrated sulfuric acid is 95% H2SO4 by mass and has a density of 1.84g/mL. How many milliliters of this acid are needed to ...
  99. Math *URGENT

    Please give the answers and solutions for each. 1.If the second term is 2 and the seventh term of a geometric sequence is 64, find the 12th term. 2. Which term if the geometric sequence 18,54,162,486,... is 3,188,646? 3. Determine the geometric mean of 8 and 288 4.Find x if ...
  100. cHEMISTRY

    wHAT IS THE SYMBOL FOR THE ION WITH 13 PROTONS AND TEN ELECTRONS? CAN U EXPLAIN HOW TO GET YOUR ANSWER, AND CAN YOU GIVE ME A WEBSITE THAT HELPS ME WITH CHEMISTRY 13 protons will be element with atomic number of 13. Look on the periodic table and see atomic number 13 is ...
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