Explicație:
1 mol de element conține 6,022 × 10²³ atomi.
a)
1 mol S..........6,022 × 10²³ atomi S
20 mol S..........x atomi S
x = 20 × 6,022 × 10²³ = 1,2044 × 10²⁵ atomi S
b) 0,02 kmol = 20 mol
1 mol Au..........6,022 × 10²³ atomi Au
20 mol Au..........y atomi Au
y = 20 × 6,022 × 10²³ = 1,2044 × 10²⁵ atomi Au
c) A(Ag) = 108 g/mol
2 kg = 2000g
1 mol Ag..........108g Ag
z mol Ag..........2000g Ag
z = 2000 : 108 = 18,51 mol Ag
1 mol Ag..........6,022 × 10²³ atomi Ag
18,51 mol Ag..........w atomi Ag
w = 18,51 × 6,022 × 10²³ ≈ 1,1146 × 10²⁵ atomi Ag
d) A(Fe) = 56 mg/mmol
1 mmol Fe..........56 mg Fe
a mmol Fe..........560 mg Fe
a = 10 mmol
1 mmol Fe..........6,022 × 10²⁰ atomi Fe
10 mmol Fe.......... b atomi Fe
b = 6,022 × 10²¹ atomi Fe
-Mihai
