Question

A compound contains only C, H, and N. Combustion of 35.0 mg of the compound produces 33.5 mg of CO2 and 41.1 mg of H2O. What is the empirical formula of the compound.

Answer 1

I'll tell you how to solve it- 
all the C ends up as CO2 
mg of C = (12.011/44.011) x 33.5 mg CO2 = 9.142 mg C 
all of the H ends up as H2) 
mg H = (2.016/18.016) x 41.1 mg H2O = 4.599 mg H 
mg N = 35.0 - 9.14 - 4.60 = 21.26 
CxHyNz represents the empirical formula 
where x = moles of C atoms, y = moles of H atoms, and z = moles of N atoms in (1 mole of) the molecule 
Calculate the moles of C, H, and N that you found. 
Determine the ratio of the moles x : y : z 
Do that and then look at my calculations- 
9.14 mg C / 12.011 mg/mmol = 0.76 millimol C 
4.60 mg H / 1.008 mg/mmol = 4.60 millinol H 
21.26 mg N / 14.006 mg/mmol = 1.52 millimol N 
divide by the smallest number (0.76) 
C = 1 
H = 6 
N = 2

Answer 2

When the atoms of a chemical reaction are represented as the whole number ratio of atoms present then it is called the empirical formula.

C atom generally forms CO₂ and H atoms as H₂.

• mg of C atom can be calculated by:

      $\dfrac{12.011}{44.011} \times 33.5 \text{ mg CO{2} }$

     = 9.142 mg C

• mg of H atom can be calculated by:

      $\dfrac{2.016}{18.016} \times 41.1 \text{ mg H{2}O}$

 

      = 4.599 mg H

• Therefore, the mg of N atom in the compound will be:

        = 35.0 - 9.14 - 4.60

        = 21.26 mg N

The empirical formula can be represented as:

CxHyNz

where, x = moles of C atoms, y = moles of H atoms, and z = moles of N atoms

Moles of the atoms can be calculated:

• 9.14 mg C / 12.011 mg/mmol

       = 0.76 millimol C

• 4.60 mg H / 1.008 mg/mmol

       = 4.60 millimol H

• 21.26 mg N / 14.006 mg/mmol

       = 1.52 millimol N

Now divide the moles calculated by the smallest number that is 0.76:

C = 1

H = 6

N = 2

So, the ratio of the moles x : y : z = 1:6:2

Therefore, the empirical formula and the compound will be:

CH₆N₂, methanediamine.

To learn more about empirical formulas follow the link:

https://brainly.com/question/14044066