Answer:
Explanation:
a ) one mole = 6.02 x 10²³ atoms
no of moles in given no of atoms
= 8 x 10⁹ / 6.02 x 10²³
= 1.329 x 10⁻¹⁴ moles .
b ) one mole of calcium = 40 gram
102 .5 g calcium
= 102 .5 / 40 moles
= 2.5625 moles
c )
no of moles in 5.04 g lead = 5.04 / 207
= 2.4347 x 10⁻² moles
= 2.4347 x 10⁻²x 6.02 x 10²³ no of atoms of lead
= 14.6568 x 10²¹ no of atoms .
d)
one mole = 6.02 x 10²³ atoms
2.85 mole = 17.157 x 10²³ atoms .
e )
moles of fluorine gas = 1.08 x 10³ / 6.02 x 10²³
= .1794 x 10⁻²⁰ moles
mass in grams = .1794 x 10⁻²⁰ x 38
= 6.8172 x 10⁻²⁰ grams
f )
no of moles in .584 g of benzene = .584 / 78
= 7.487 x 10⁻³ moles
no of molecules = 6.02 x 10²³ x 7.487 x 10⁻³
= 45.07 x 10²⁰ molecules .
g )
moles of atoms = 5.09 x 10⁹ / 6.02 x 10²³
= .8455 x 10⁻¹⁴ moles
mass in gram = .8455 x 10⁻¹⁴ x 1
= .8455 x 10⁻¹⁴ g
h )
.45 moles of Ca₃PO₄ = .45 x 6.02 x 10²³ molecules
= 2.709 x 10²³ molecules of Ca₃PO₄
no of atoms of Ca = 3 x 2.709 x 10²³
= 8.127 x 10²³ atoms of Ca .
