posted by jaz .
Find the mass in grams.
a. 4.30 x 10^16 atoms He, 4.00 g/mol
b. 5.710 x 10^23 molecules CH4, 16.05 g/mol
c. 3.012 x 10^24 ions Ca^2+, 40.08 g/mol
a. divide the atoms by avogradros number to the moles, then multiply by 4g/mol
You must learn to do these yourself. They are worked the same way I showed you earlier in the evening except there are two factors. One to convert molecules or atoms to moles and the second to change from moles to grams.
#molecules x (1 mole/6.02 x 10^23 molecules) x (zz grams/mole) = ?? grams.
so a= 1.075*10^16