moles

  1. A

    Moles as Intermediate Questions

    What mass of CuBr is found in 4 L of 0.432 mol/L solution ? I n the boxes below place the following information: the moles of CuBr the molar mass of CuBr the mass of CuBr What mass of KNO3 is found in 0.44 L of 1.55 mol/L solution ? I n the boxes below place the following information: the moles...
  2. T

    Calculating number of moles from Keq

    Hello, I am having trouble with a question on my lab report that is as follows: "Calculate the number of moles of reactants and products in an equilibrium mixture. Complete the ICE table below." I am given the Keq which is 3 and the initial amount of acid and alcohol which are (0.25/V) each...
  3. J

    Cannot grasp how to find number of moles & mass of a solute

    I'm in week 2 of college chemistry and I am completely lost on how to work out one of my chapter problems. :confused: It's: Calculate the number of moles and the mass of the solute in each of the following solutions: (a) 325 mL of 8.23 × 10^−5 M KI, a source of iodine in the diet (b) 75.0 mL...
  4. B

    Theoretical Yield Ni + 2HCl yields NiCl2 + H2

    Hey All, I have the balanced equation of Ni (s) + 2 HCl (aq) -> NiCl2 (aq) + H2 (g) A.) If 12.0 moles of HCl were reacted, how many moles of Ni would be needed such that there was no excess? B.) What is the theoretical yield (in grams) of NiCl2 from reacting 12.0 mol HCl? C.) If 12.0 mol of...
  5. I

    Can you help me with these problems?

    Hi everyone,I just wanted to ask if you can help me with some of the problems that I have for homework.Although they are simple to most people, to me and some of my classmates , they are not, primarily because of our teacher.Thank you in advance. 1.How many moles of Calcium chloride hexahydrate...
  6. S

    How can you determine the mass, volume, or moles?

    I had a quiz today, and had no idea what the instructor expected us to do based off the information given. I'm trying to figure out how we were supposed to get the mass, volume, or moles to help solve the problems. I don't want any answers, just advice on how to use the information to get me to...
  7. 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!:(
  8. C

    Calculate moles

    Question: Nitric acid is extensively used in the manufacturing of fertilizer. A bottle containing 75mL of nitric acid solution is labelled 6.0M nitric acid. How many moles of nitric acid is in the bottle? My answer: M=moles of solute / moles of solution thus moles of solute = M x moles of...
  9. J

    How many fluorine atoms are present in 10 moles of SF6 (Sulfur Hexafluoride)

    I know I have to use avogadro number. The correct answer is 4 * 10 ^ 25 but how do you get that answer. Please help.
  10. D

    Energy of reaction: per moles of what?!

    Disclaimer: I've never had a chemistry class in my life. I'm reading a journal article that states the following: Thiosulfate + 2 Oxygen + Water → 2 Sulphate + 2 H+ has the standard Gibbs energy of −766 kJ/mol at 25ºC. So, this is energy produced per mole of what?! Reactant? Product? If so...
  11. T

    Calculations involving moles and percentage yield

    Hello all! I'm just starting out on chemistry and I don't even know where I would begin with these questions: What volume of a 2.40 mol/L magnesium bromide solution would contain 3.40 x 10^23 atoms of bromine? The reaction of 2.0g of Br2 with 4.0g of F2 produced BeF5 in 45% yield. How many...
  12. N

    Molarity and Number of moles please help..what to do next?

    The question goes like this: 10.0ml of a 0.1M K2Cr207 solution is added to 10.0ml of a 0.1M Pb(NO3)2 solution. What mass of PbCr207 is formed?? 0.1 = number and of moles of K2Cr207 divided by 0.01L, and number of moles is given mass divided by 294g/mol (molar mass), which gives 2.94g and with...
  13. O

    Calculating Moles

    I'm stuck on this question. Assistance would be greatly appreciated! Thank you. The question is: 1 Liter of a 5% glucose (w/v) solution is to be administered intravenously to a patient. How many moles of glucose (C6H12O6) will the patient receive from this IV?
  14. C

    mg to Moles

    I am stuck on a question and don't know if I am even doing this right. Here is the question...Caffeine has the formula C8H10N4O2. If an average cup of coffee contains approximately 125 mg of caffeine, how many moles of caffeine are in one cup? So far I have: 125mg of caffeine = .125g 193.9g...
  15. C

    mg to moles

    I am stuck on a question and don't know if I am even doing this right. Here is the question...Caffeine has the formula C8H10N4O2. If an average cup of coffee contains approximately 125 mg of caffeine, how many moles of caffeine are in one cup? So far I have: 125mg of caffeine = .125g 193.9g =...
  16. W

    Given moles, reaction, and Kc, calculate equilibrium concent'n at a different volume

    For the reaction i2 + BR2 = 2IBr Kc= 280 Suppose that 0.460 mol IBr is allowed to reach equilibrium in a 2.00 L flask... 1. What is the equilibrium concentration of IBr? 2. What is the equilibrium concentration of I2? 3. What is the equilibrium concentration of Br2? I've seriously spent about...
  17. J

    Adjusting for partial pressure of water wapor when calculating moles of gas produced

    In my chem lab, we did an experiment with electrolysis reactions. In the lab, hydrogen gas was produced and collected in an inverted buret that was originally filled with a sulphuric acid solution. One of the questions in the lab booklet asks me to find the number of moles of hydrogen gas...
  18. M

    Titration and equilibria?

    A mixture of 0.5 moles of ethanoic acid and 1.0 moles of ethanol was shaken for a long time to reach equilibrium. The whole mixture was titrated quickly with 1.00 mol dm^3 sodium hydroxide and 80cm^3 of alkali were required. (i) Write an equation for the reaction between ethanoic and ethanol...
  19. M

    Yet Another moles/gas law question :( Please Help me :D

    Hi all, sorry to ask another question but this is for an assignment and I can't leave them blank :( A small amount of zinc granules were reacted with an excess of dilute HCL according to the following equation: Zn(s) + 2HCl(aq) --> ZnCl2(aq) + H2(g) The hydrogen gas produced was collected...
  20. M

    Chemistry Moles and Gas Law Question? Please Help?

    Hi! So the question is: Hydrochloric acid of concentration 2.0 mol dm^-3 is used to descale a kettle containing 25 grams of scale (calcium carbonate) (i) what volume of water containing 0.002 ml dm^-3 calcium hydrogen carbonate Ca(HCO3)2 would need to be boiled to produce this amount of...