1. S

    Mass spectro

    Hello:) Can anyone help me with this question? I don't understand it :(:confused:
  2. S

    Fluorine Peak Height Difference on Mass Spec

    I have these three compounds with a Fluorine attached to different carbons. If you look at the chromatograph, two of the Fluorine peaks (the 213) are relatively the same size, however one of the compounds the fluorine does not come off as readily (3-fluoro-AMB). I've been researching on why this...
  3. 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...
  4. 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...
  5. T

    Determine Ti in Ilmenite sample using Inductively Coupled Plasma Mass Spectrometry

    How to determine Ti in Ilmenite sample using Inductively Coupled Plasma Mass Spectrometry?
  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. F

    Is there any change in mass as the electron changes energy levels.

    Does anything happen to the electron, as it changes energy levels, does its mass increase, or decrease, or velocity speed up, or slow down.? The electron will speed up when its away from the nucleus, when its in a higher shell like shell level 3. But is there anything like a visible sign that...
  8. J

    How would i determine the mass of the other Isotope PLEASE HELP

    Silver has two naturally occurring isotopes. The first, with a mass of 106.9 amu, has a natural abundance of 51.85%. Given its atomic weight of 107.9 amu, determine the mass of the other isotope. I know the answer is 109.0 amu. But how do you get it. Please Help...
  9. A

    Calculate pH of a solution given the mass and the acid dissociation constant

    Hi everyone! The problem: "2,50 g of ammonium chloride NH4Cl is dissolved in water and the volume of the solution is 100 cm^3. At current temperature, the Ka for NH4^+ is 5,7 * 10^-10 mol/dm^3 What pH does the solution of ammonium chloride have?" My attempt: H2O + NH4^+ <=> H3O^+ + NH3...
  10. S

    How can I find out the mass in this equation

    given the thermochemical equation: 2Cu2O(s) ------- 4Cu(s) + O2(g) delta H : +333.8 calculate the mass of copper produced when 1.47 x 10^4 is consumed in the reaction the answer is 11.2 kg BUT HOW ?:confused:
  11. A

    Mass %

    Find the mass % of all elements in CuSO4, and then find mol % in CuSO4 I found that there is w(Cu)=40% w(O)=40% and w(S)=20%, so this means in 100g that there is 40grams of Cu 40grams of O and 20grams of S, now Im having trouble to get right answer of x=n/n(sum of all elements in CuSO4) i tried...
  12. W

    Mole and Molar Mass

    Is the number of atoms in 0.5 mol of oxygen gas and 0.5 mol of iron the same? My answer is NO because: Oxygen gas exists as molecules (2 oxygen atoms in one oxygen molecule) Therefore, in 0.5 mol of oxygen gas, there were 0.5 x 2 x 6 x 10^23 = 6 x 10^23 oxygen atoms. But, 0.5 mol of iron has...
  13. C

    Percentage by mass of Aresenic

    Arsenic can be oxidized to arsenic (V) acid, H3AsO4. This acid oxidises I- ions to I2, which can be estimated by titration against a standard thiosulphate solution: As + 5HNO3  H3AsO4 + 5NO2 + H2O H3AsO4 + 2HI  H3AsO3 + I2 + H2O If 0.1058 g of a sample containing arsenic required 28.7...
  14. S

    Given mass and Atoms find Unknown element

    5.44 grams of an element contains 3.24x10^22 atoms which element is this? I know avogadros # is 6.022x10^23 Not really sure what to do, I have been in my university chemistry class for over a month now. This is not a test question or an assignment, just a practice sheet worth no marks.
  15. 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?
  16. A

    Percent mass sugar in water

    Hi, If I put 2.00g of sugar in 50.0mL of water, what is my percent mass sugar? Is it just 4.00%, or do I need to do some calculations to the water data. Thanks so much in advance.
  17. S

    Mass of Copper in Penny! HELP!!

    We preformed an experiment in which we dissolved a 2.2453g penny in 20mL nitric acid. The dissolved penny and acid was transferred to a 100mL flask and diluted with distilled water. 25mL of this solution was pipetted to another 100mL flask, 10mL of ammonia was added, then it was again diluted to...
  18. H

    Stoichiometric Virtual Lab Help?

    Hey, I'm new here! Anyway, I'm doing a virtual chemistry lab on stoichiometric. I have completed the actual experiment; what I'm stuck on are the questions. Here is one of the questions: Below is the balanced equation for the reaction. Review the results of your...
  19. B

    Converting mg/mL to sample mass?

    Hi everyone. I've got a problem that I've never been taught the solution to and I'm having difficulty in finding a clear answer. Here is my problem. I have an aspirin tablet and I want to find out if the amount of aspirin content in the tablet is the same as advertised on the box. It was...
  20. B

    A Molecule With a Similar Molar Mass as CCl4?

    I need to find a molecule that has a similar mass as CCl4 but it can't be another non-polar molecule. PCl3 was the closest I could get it but had a lower melting and boiling point. I need to prove that a polar molecule with a similar molar mass will have a higher melting and boiling point...