Question

intr un diamant avand forma de cub cu latura 2 cm si densitatea 3,5 g cm cub se gasesc un nr necunoscut x de atomi de carbon.determinati x.

Answer 1

l cub= 2 cm
d=3.5g/cm cub
V cub= $l^{3}$
V cub= $2^{3}$ = 8 cm cubi.
d= m/V => m=V x d
m= 8 * 3.5 = 28 g diamant adica, Carbon
M C= 12 g/mol
m C = 28 g
n = m/M=> n C = m C/ M C 
n C = 28g / 12 g/mol = 2.33 mol C
1 mol C ... 6.023 × $10^{23}$ atomi
2.33 mol C .... x 
x = $\frac{2.33 * 6.023 *10^{23}}{1}$ 
x = 1.403359 ×$10^{24}$