200.0 grams of an organic compounds known to contain 98.061 grams of carbon, 10.381 grams of hydrogen, 32.956 grams of oxygen and the rest is nitrogen. what is the empirical formula of the compound? what is the molecular formula of the compound if its molar mass is 194.101?

1. The empirical formula is C₄H₅N₂O

2. The molecular formula is C₈H₁₀N₄O₂

Explanation:

The following data were obtained from the question:

Mass of compound = 200 g

Carbon (C) = 98.061 g

Hydrogen (H) = 10.381 g

Oxygen (O) = 32.956 g

Empirical formula =?

Molecular formula =?

Next, we shall determine the mass of nitrogen in the compound. This can be obtained as follow:

Nitrogen (N) = 200 – (98.061 + 10.381 + 32.956)

Nitrogen (N) = 200 – 141.398

Nitrogen (N) = 58.602 g

1. Determination of the empirical formula of the compound.

C = 98.061 g

H = 10.381 g

O = 32.956 g

N = 58.602 g

Divide by their molar masses

C = 98.061 /12 = 8.172

H = 10.381 /1 = 10.381

O = 32.956 /16 = 2.060

N = 58.602 /14 = 4.186

Divide by the smallest

C = 8.172 /2.060 = 4

H = 10.381 / 2.060 = 5

O = 2.060 / 2.060 = 1

N = 4.186 / 2.060 = 2

Thus, the empirical formula of the compound is C₄H₅N₂O

2. Determination of the molecular formula of the compound.

Empirical formula of the compound => C₄H₅N₂O

Molar mass of compound = 194.101 g/mol

Molecular formula =.?

[C₄H₅N₂O]n = 194.101

[(12×4) + (1×5) + (14×2) + 16]n = 194.101

[48 + 5 + 28 + 16]n = 194.101

97n = 194.101

Divide both side by 97

n = 194.101 /97

n = 2

Molecular formula => [C₄H₅N₂O]n

=> [C₄H₅N₂O]2

=> C₈H₁₀N₄O₂

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.