problems

  1. K

    Need Help Solving Problems!!

    A) Equal masses of water at 20 Celsius and iron at 40 Celsius are put together in a Styrofoam cup. The water has a specific heat of 1 cal/g C and the iron has a specific heat of 0.113 cal/g C. What do you think the final temp will be of both the water and the iron in the Styrofoam cup? Show your...
  2. H

    Cooling Chemicals

    Hey Guys, I have been given a class challenge on finding a way to make a device that could cool the body safely using a chemical reaction. I am having a huge mind blank and can't think of anything. Could someone help? Thanks :)
  3. M

    Need help with these two Geochemistry Problems

    1. Water from a septic tank drainage field enters an aquifer. The water contains a significant amount of dissolved organic carbon. Oxidation of this dissolved organic carbon adds CO2 to the groundwater. The system is effectively isolated from the atmosphere and after the breakdown of the...
  4. kamigreed

    Series Of Chemistry Problems

    Hi guys, I am new to this forum and I was hoping if you guys can help me out with these questions I have tried but I am unsure whether they are correct or not. These are questions to practice for my upcoming examinations so I am hoping to score well for it since I do not perform well enough...
  5. J

    Need help with a couple chemistry problems

    Please help me with these questions: 1.) A 100 ml solution contains 25.0g KOH and has a density of 1.21 g/ml. What is the percent KOH in the solution? 2.) 20.1 ml of 1.00 M NaOH is used to titrate 75.0 ml of an acid solution to the phenolphthalein end point. What is the molarity of the acid...
  6. A

    Please help with these solution problems

    1.) If i make a solution by adding 83grams of sodium hydroxide to 750 mL of water.. a) what is the molality of NAOH in this solution? b) what is the percent by mass of NAOH in this solution? C) what is the mole fraction of NAOH 2) Explain how you would make 450 mL of a 0.25M Calcium chloride...
  7. D

    some multiple choice problems

    I included the question and the possible answers and what I believe is the correct one (I put my answer in magenta), but for the ones i got wrong, can someone explain the right answer and why it is such? Thanks 1. (I have no idea how to do this one since it's been so long since I last did...
  8. J

    Formulas to calculate problems

    Can someone tell me the formulas to calculate these problems I have for my chemistry class? I can'y find a formula that uses just the given information to do the problems. Here they are: 1 Considering the reaction: 2KClO3 → 2KCl + 3O2 How...
  9. E

    Problems with chemical bonding

    I would be grateful if you help me clear my ideas for some of the basic concepts about chemical bonding: First: How do you determine the length of a molecular bond Question: Which of these bonds is less longer: O=O C=0 C-C or c(with three lines)C Second: Bonding stability Question: Which of...
  10. T

    Can you please check these? (Stoichiometry problems)

    So i'm generally good with Molarity problems but on a few they threw mg/ml into the mix and its throwing me off. I think i did these right but could someone check them? The first problem is, you weigh out exactly 0.250g of CaCo3 (form. weight= 100.09g/mol) and disolve it in exaclty 250 ml of...
  11. S

    Organic Chemistry problems help..

    Hi everyone! A test is near and I have some difficulties with some problems in organic chemistry, I would sincerely appreciate any help. Most of them consist of finding the organic compound (mostly Alkenes, alkanes, alkines, alkynes and benzene), my troubles are when the relative density...
  12. M

    Solving Equilibrium Problems

    Hydrogen iodide decomposes according to the reaction 2HI(g)<-->H2(g)+I2(g) A sealed 1.50 L container initially holds 0.00623 mol of H2, 0.00414 mol of I2, and 0.0244 mol of HI at 703 K. When equilibrium is reached, the concentration of H2 is 0.00467 M. What are the concentrations of HI and...
  13. M

    please help me! i keep having problems

    ok so im trying to make a waterbased hair pomade or a really thick hair gel. so i bought glycerin, sea kelp extract, carbomer 940, peg-40 hydrogenated castor oil, propylene glycol, ceteareth-20, and peg-7 glyceryl cocoate. i dont know what i am doing i just read a bunch of labels of products...
  14. S

    Kinetics problems, please I need your help...

    Hi everyone, I really need your help. Although I've been stuying here and there from the internet, someone at my class stole my book and it's not the same, I still have unclear things on my mind... I have a test tomorrow for the kinetics chapter and I need your help with the following problems...
  15. M

    Heat absorbed per mole and other math problems

    Hello, We're working on bond energies in my chemistry course, and I'm having some trouble with bond energies. I used the Table of Bond Energies, but didn't end up even close to the answer for this and other math-related questions: I'm not too sure how to know which is which. Thanks!
  16. N

    concentration and molarity problems

    I need help with these problems please! ch. 9 drills 17. a) a stock bottle of aqueous sulfuric acid indicates that the solution is 90.0% H2SO4 by mass and has a density of 1.2 g/mL. Calculate the molarity of the solution (Ans 11.0 M) e) If the concentration of Na+ (sodium ion) in an...