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Ex1
1) N =Na xn
N = 6,02x10²³x2,78x10⁻³
N = 1,67x10²¹

2) N =Na x n
n = N/Na
n = 9,78x10²¹/6,02x10²³
n = 1,62x10⁻² mol

Ex4
1)
M = 8M(C)+9M(H)+2M(O)+M(N)
M = 8x12,0+9x1,0+2x16,0+14,0
M = 151,0 g/mol
2)
M = 9M(C)+10M(H)+3M(O)
M = 9x12,0+10x1,0+3x16,0
M = 166 g/ mol

Ex 6
1) n = m/M
n = 0,500/

2)
m = nxM
m = 8,04x10⁻³x