A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 4 years ago

HELP! I have a variety of materials and I have to measure the mass, and calculate the number of mole, the number of individual units (molecules/compounds), and the number of atoms for a variety of samples.

  • This Question is Closed
  1. anonymous
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I already have the mass of four materials: Chalk (CaCO3): 2.04 g, Water (H2O): 32.0 g, Iron (fe): 15.87 g Copper (Cu): 0.59 g I know how to find the molar mass (calculate the number of moles?) but I don't know how to calculate the number of individual units (molecules/compounds), and the number of atoms for a variety of samples.. Please help!!

  2. JFraser
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    1 mole of anything is 6.022x10^23 humber of those things. 1 mole of calcium carbonate will have that many molecules of that substance. This means you can use the equality as a conversion factor: \[2.04g CaCO{_3} * (\frac{1mol CaCO{_3}}{100g CaCO{_3}})*(\frac{6.02x10{^2}{^3}molecules CaCO{_3}}{1mol CaCO{_3}}) \]

  3. anonymous
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Is number of entities (basically what you showed me where n=NA) the "number of individual units"? How do I find the number of atoms for a variety of samples? A teacher told me that I should just count how many atoms there are in a compound.. like say Al3O2, which means there are 3 Aluminum, and 2 oxygen or 5 in total.

  4. JFraser
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    A single molecular unit of something like Al2O3 has 5 atoms total, correct. 1 MOLE of Al2O3 will have 6.022x10^23 molecules, and also 2 moles of Al atoms and 3 moles of O atoms, for 5 MOLES of atoms total. A mole is a term of grouping, just like a dozen. If you had 1 dozen eggs, you'd have just as many THINGS as if you had 1 dozen elephants. The MASSES of those things would be very different, but the number of items would be the same.

  5. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.