Question

NutraSweet is 57.14% C, 6.16% H, 9.52% N, and 27.18% O by mass. Calculate the empirical formula of NutraSweet and find the molecular formula. (The molar mass of NutraSweet is 294.30 g/mol).

Answer 1

we have mass of each elements as:

C: 57.14 g

H: 6.16 g

N: 9.52 g

O: 27.18 g

Divide by molar mass to get number of moles of each:

C: 57.14/12.01 = 4.7577

H: 6.16/1.008 = 6.1111

N: 9.52/14.01 = 0.6795

O: 27.18/16.0 = 1.6987

Divide by smallest:

C: 4.7577/0.6795 = 7

H: 6.1111/0.6795 = 9

N: 0.6795/0.6795 = 1

O: 1.6987/0.6795 = 2.5

multiply by 2 to get simplest whole number ratio:

C: 7*2 = 14

H: 9*2 = 18

N: 1*2 = 2

O: 2.5*2=5

So empirical formula is:C14H18N2O5

Molar mass of C14H18N2O5 = 14*MM(C) + 18*MM(H) + 2*MM(N) + 5*MM(O)

= 14*12.01 + 18*1.008 + 2*14.01 + 5*16.0

= 294.304 g/mol

Now we have:

Molar mass = 294.3 g/mol

Empirical formula mass = 294.304 g/mol

Multiplying factor = molar mass / empirical formula mass

= 294.3/294.304

= 1

So molecular formula is:C₁₄H₁₈N₂O₅