[test1234567]

1)If one atomic mass unit is equal to 1.6606 x 10-24 g, what is the mass in grams of 19145 atoms of Cu?

2)Each molecule of CH4, methane, consists of 1 atom of C and 4 atoms of H. If you have 296.098 g. of CH4, how many molecules of CH4 do you have ?

3)The radioactive isotope Thallium-201 (201Tl) is used in medical diagnosis and treatment. A gamma ray emitted by an atom of 201Tl has an energy of 0.167 MeV. (1 MeV is 1 x 106 eV and 1 eV = 1.6022 x 10-19 J). What is the frequency in Hz of this gamma ray?

4)How many moles of H2 are produced when 6.86 grams of CaH2 and 1.82 grams of H2O react ?

thanks so much

[enahs]

http://www.chemicalforums.com/index.php?topic=9037.0
#4

We are here to help, not do your work for you.

[X-18]

Hello:

enahs is right, we can't do you work for you. Although I think this should steer you in the right direction.

Numbers 1 and 2 you need to use Avogadro's number for (molecules / mol) hint: didn't put the stuff in brackets for my health!

Number 3 is actually a physics question, it requires 2 formula. You should have a formula sheet or something with them written down.

Number four I have written the steps down and explained it here:
http://www.chemicalforums.com/index.php?topic=12424.0

Question to enahs, mod, or the like, is that amount of info alright? I'm new here so I wasn't sure if I should put the two physics formula down. Please PM me and tell me if I'm still safe . Thanks.

X-18