Explanation:
The formula mass of a molecule (also known as formula weight) is the sum of the atomic weights of the atoms in the empirical formula of the compound.
a. NO2
N = 14
O = 16
NO2 = 14 + (16 * 2) = 46 amu
b. C4H10
Empirical formular = C2H5
C = 12
H = 1
C2H5 = (12*1) + (1*5) = 12 + 5 = 17 amu
c. C6H12O6
Empirical formular = CH2O
C = 12
H = 1
O = 16
C2H5 = 12 + (1*2) + 16 = 30 amu
d MgBr2
Mg = 24
Br = 80
MgBr2 = 24 + (80*2) = 184 amu
e. HNO2
H = 1
N= 14
0 = 16
HNO2 = 1 + 14 + (16*2) = 47 amu
f. CBr4
C= 12
Br = 80
CBr4 = 12 + (80*4) = 332 amu
g. Cr(NO3)3
Cr = 52
N = 14
O = 16
Cr(NO3)3 = 52 + 3[14 + (3*16)] = 238 amu
