1 / 18

What is the mass in grams of one atom of a particular isotope?

What is the mass in grams of one atom of a particular isotope?. 12 C 6. Consider 1 atom of C-12. The isotope notation is:. 6 protons. X 1.67 x 10 -24 g/proton = . 1.002 x 10 -23 g. 6 neutrons. X 1.67 x 10 -24 g/neutron = . 1.002 x 10 -23 g. 6 electrons.

gregory
Download Presentation

What is the mass in grams of one atom of a particular isotope?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. What is the mass in grams of one atom of a particular isotope? 12 C 6 Consider 1 atom of C-12. The isotope notation is: 6 protons X 1.67 x 10-24 g/proton = 1.002 x 10-23 g 6 neutrons X 1.67 x 10-24 g/neutron = 1.002 x 10-23 g 6 electrons X 9.11 x 10-27 g/electron = 5.466 x 10-26 g 2.010 x 10-23 g/atom

  2. 2.010 x 10-23 g/atom is a very small amount. Scientists cannot measure small quantities like this in the lab. Scientists want (NEED!) to be able to work with a useable quantity such as 10 grams or 50 grams. Is there a convenient way to measure larger quantities of atoms?

  3. Why not use the average atomic mass that is already on the periodic table? It is already a relative mass, right? Why reinvent the wheel?

  4. But the atomic mass on the chart is in AMU, not grams! We do not have an AMU balance!

  5. Then let’s convert the number on the periodic chart from AMU to grams!

  6. We already know that 1 atom of C-12 has a mass of 2.010 x 10-23 g. (This is also equal to 12 amu!) We also want the atomic mass of 12.0 amu to become 12.0 g. Let’s review what we already know…….. So, the problem becomes this…….. 2.010 x 10-23 g/atom C-12 X ????? atoms = 12.0 g C-12

  7. ????? = 6.0 x 1023 atoms This quantity is called a MOLE.

  8. 12 steers 12 dinosaurs 12 flags A MOLE (mol) is just a word representing a quantity. What does dozen mean? Yep, it means 12. But 12 what?

  9. Just like the word dozen can stand for 12 things, the mole stands for 6.02 x 1023 things. Things, however, are limited to Atoms Molecules Ions

  10. You have finally arrived at the MOLE. You can now start applying this new knowledge in many different ways! Have Fun!

  11. Stuff to Do With the Mole

  12. What Is The Mass Of 1 Mole Of Cu Atoms? This is easy! We just learned that 1 mole of an element is equal to the atomic mass listed on the periodic table. 1 mole of Cu atoms has a mass of 63.5 grams. Remember,1 atom of Cu has a mass of 63.5 amu. 1 mole of Cu atoms has a mass of 63.5 grams! Menu

  13. What Is The Mass Of 1 Mole Of Cu(NO3)2? This is easy! We just learned that 1 mole of a compound is equal to the sum of the atomic masses of each element in the compound. 1 mole of Cu atoms has a mass of 63.5 grams. + 2 moles of N atoms have a mass of 28.0 grams. + 6 moles of O atoms have a mass of 96.0 grams. One mole of Cu(NO3)2 has a mass of 187.5 g/mole. Menu

  14. How many moles of Cu atoms are there in 75 g of Cu? Molar mass Cu = 63.5 g/mol Use this as a proportion! If we know that… then we also know that… 63.5 g Cu 1 mole 75 g Cu x mole = X = 1.18 mol Another way to set this up…. 75 g Cu x 1 mole Cu = 1.18 mol 63.5 g Cu Menu

  15. How many moles of Cu(NO3)2 are there in 150 g of Cu(NO3)2? Molar mass Cu(NO3)2 = 187.5 g/mol Use this as a proportion! If we know that… then we also know that… 187.5 g Cu(NO3)2 1 mole 150 g Cu(NO3)2 x mole = X = 0.8 mol Another way to set this up…. 150 g Cu(NO3)2 x 1 mole Cu(NO3)2 = 0.8 mol 187.5 g Cu(NO3)2 Menu

  16. How many atoms of Cu are present in 200 g of Cu? You have to expand your mind a bit on this one. Is there a direct conversion between numbers of atoms and grams of an element? NO! Well, what do we know that will help us, then? • We know there are 6.02 X 1023 atoms in a mole of something. • We know 63.5 g of Cu is equal to one mole of Cu atoms. How can we use these two facts to help us solve the problem?

  17. How many atoms of Cu are present in 200 g of Cu? • Find out how many moles is equal to 200 g Cu. • Find out how many atoms there are in this many moles. 1. Molar mass Cu = 63.5 g/mol Use this as a proportion! 63.5 g Cu 200 g Cu ------------ = ------------- x = 3.15 moles Cu 1 mole x mole 2. There are 6.02 X 1023 atoms of Cu in a mole of Cu. 6.02 X 1023 atoms Cu x atoms Cu --------------------------- = ------------------- x = 1.9 X 1024 atoms 1 mole Cu 3.15 moles Cu of Cu

  18. How many atoms of Cu are present in 200 g of Cu? A much shorter way…Dimensional Analysis! 1mole Cu 6.02 x 1023 atoms Cu 200 g Cu x ------------- x -------------------------- = 63.5 g Cu 1 mole Cu x = 1.9 X 1024 atoms of Cu Menu

More Related