finding

  1. C

    Finding solubility constants in a titration

    For a lab we are doing in class, we were given this data: Mass of Potassium Hydrogen Phthalate: 0.10g (this was in the Erlenmeyer flask) Volume of Water: 50 mL (also in the Erlenmeyer flask) Volume of Calcium Hydroxide Used to Titrate: Trial 1-162.80mL, Trial 2-190mL, Trial 3-163.10 mL...
  2. S

    Finding pH of solution (KOH, HCl, NaCl)

    Solution made of 230 mg KOH 8.71 ml 0.802 mol/l solution of HCl 3 g m/m% NaOH = 3.97 diluted to 618 ml m/m% is weight percent of substance. What is pH of this solution?
  3. C

    Finding unknown element

    Hi folks! A chem student here. I have a homework problem that I feel might be a curve ball and thought i should get a second opinion. Here it goes.... ​A mass of 0.6807g of carbon and a mass of 3.453g of an unknown element contain equal number of atoms.Find the identity of the unknown element...
  4. B

    Finding the molar mass from an Osmotic Pressure

    An unknown, non-ionizing compound with a mass of 0.108 g is dissolved in water to make 100.0 mL of solution. If the solution has an osmotic pressure of 0.169 atm at 20.8 ºC, what is the molar mass of the substance? -------- The answer is 154.1g/mol. I got this question wrong and can't figure...
  5. X

    Finding Riboflavin Concentration in Tablet

    I need help understanding how to solve for the riboflavin concentration in a tablet. Here's the problem: The ribofalvin concentration in an unknown powder solution is 50.4 ppm. The total volume of the unknown powder solution is 250.00 mL. What is the concentration in the tablet (mg...
  6. J

    finding heat from moles

    How much heat is liberated in the reaction of 5.0 g of Al and 20.0 g of Fe2O3 producing extensively Fe and Al2O3? deltaH(Al2O3)= -1676 deltaH(Fe2O3)= -824 I'm having such a hard time figuring out this problem, please help me!:(
  7. S

    Finding molar mass of copper

    Hi, in my experiment I determined that copper has a specific heat capacity of 0.275 J/(g* Celsius). How do I approximate it's molar mass using this piece of information?
  8. M

    Finding Lambda Max for Nitrobenzene

    Hello, I'm embarrassed to say I don't understand this question where I need to find lambda max of the lowest energy optical absorption band of nitrobenzene. I have to use SciFinder to locate the answer. I figured that the search would be fairly easy but everything article I find containing...
  9. S

    Finding the percent concentration of hydrogen peroxide in a consumer product?

    We were given a lab last week in Chemistry class, the problem was to find the percent concentration of hydrogen peroxide in a consumer product. A titration happened between acidic hydrogen peroxide solution and KMnO4. Previously I calculated the KMnO4's molarity and placed it in the equation...
  10. E

    Finding activities and concentrations?

    Alright, So I have this problem: http://i.imgur.com/C8zCeuD.png. And I believe I've been able to successfully answer part A and B. However, on C, I've been completely lost for the last hour or so. How do I find the concentrations of these products, when I know that the activity coefficients...
  11. F

    finding composition in mol %, anyone?

    Copper can have improved wear resistance if alloyed with ceramic alumina, Al2O3. If a copper alloy has 8.5 wt.% Al2O3, What is its composition in mol %?
  12. C

    Finding the element

    Can someone check my answers please.It would be helpful. Find the element ,what is its electronic configuration and predict how each of these bond. 1.)R^15-pHOSPHORUS -2.8.5 non metal gain electrons 2)Z^9-Florine 2.7-Metal which gains electrons 3)Q^11-Na-2.8.1-metal which looses electrons
  13. D

    finding a % of an element in the compound

    Hi guys, I have a problem here. Tried to find this for a few days now however been struggling... :confused: My task is: Calculate % of iodide in the tin compound of each of the three samples and hence determine the formula of the compound. The only information I have is mass of all three...
  14. M

    finding a concentration using an msds sheet

    I would like to know the concentration of the sodium metabisulfite into the following msds sheet http://www.chemspecworld.com/fileshare/product_msds//pro/coffeestainremover.pdf i cannot find anything except i thought in section IX : "physical and chemical data" there is something that says...
  15. S

    Finding oxidation state of metal center?

    what is the oxidation state of the metal center in of [Cr(CN)ClF2(NH3)2]- Could anyone explain how exactly to know the charges of each component? I think the charge of (NH3)2 is -2 but Im not sure how to find the rest of the charges. Thanks for any insight.
  16. P

    Thermodynamics Question: Finding Equilibrium Constant

    Calculate the standard free energy change for the combustion of methanol at 25 deg. C. 2 CH3OH(l) + 3 O2(g) -> 2 CO2(g) + 4 H2O(g) My answer was -1.37E3 kJ, which was right. Now the part I need some guidance on: If instead of the theoretical 2 mol, the actual reaction uses reaction...
  17. I

    finding ion concentrations of solution in equilibrium

    An excess amount of silver chloride is added to a beaker of 2 M sodium cyanide. Calculate the concentration of all ions, other than OH- and H+, that are in solution once the system reaches equilibrium. (Hint, there should be 5 other ions present) Please explain through your answer!! I'm really...
  18. S

    Finding pH

    If the pKa of uric acid is 3.89 and the concentration is .0050 M, what is the pH of the solution? My work: Ka=10^-3.89 Ka=1.29x10^-4 1.29x10^-4 = x^2 / .0050-x 6.44x10^-7 - 1.29x10^-4x = x^2 x^2 + 1.29x10^-4x - 6.44x10^-7 = 0 quadratic [-1.29x10^-4 +/- sqrt( (1.29x10^-4)^2) -...
  19. Purplepiscean

    Chemistry, please help? Finding Kb?!?!?

    A 0.25 m solution of diethylamine, (ch3ch2)2nh has a ph of 12.15. What is the kb of diethylamine?
  20. S

    Finding initial rate

    Ok so I know you have to compare a concentration of a reactant that changes and the other stays constant. comparing experiment 1 and experiment 3 for NO , the concentration increases by 4 and the initial rate increases by ~4.01. I would estimate that to be an order of 1. Likewise for cl2...