Question

What is the empirical formula for a substance that contains 3.730% hydrogen, 44.44% carbon, and 51.83% nitrogen by mass?\?

Answer 1

Given data:

Hydrogen (H) = 3.730 % by mass

Carbon (C) = 44.44%

Nitrogen (N) = 51.83 %

This means that if  the sample weighs 100 g then:

Mass of H = 3.730 g

Mass of C = 44.44 g

Mass of N = 51.83 g

Now, calculate the # moles of each element:

# moles of H = 3.730 g/ 1 g.mole-1 = 3.730 moles

# moles of C = 44.44/12 = 3.703 moles

# moles of N = 51.83/14 = 3.702 moles

Divide by the lowest # moles:

H = 3.730/3.702  = 1

C = 3.703/3.702 = 1

N = 3.702/3.702 = 1

Empirical Formula = HCN