Question

Calculate the formula mass for each compound. a. NO2 b. C4H10 c. C6H12O6 60. Calculate the formula mass for each compound. a. MgBr2 b. HNO2 c. CBr4 d. Cr(NO3)3

Answer 1

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