Question

diazomethane is a highly poisonous, explosive compound because it readily evolves n2. diazomethane has the following composition by mass: 28.57% c; 4.80% h; and 66.64% n. the molar mass of diazomethane is 42.04 g>mol. find the molecular formula of diazomethane, draw its lewis structure, and assign formal charges to each atom. why is diazomethane not very stable? explain.

Answer 1

The molecular formula of diazomethane is CH2N2. The Lewis structure of diazomethane consists of a carbon atom bonded to two nitrogen atoms and two hydrogen atoms. Diazomethane is not very stable due to the presence of a highly strained nitrogen-nitrogen triple bond which can easily break.

Step-by-step explanation:

The molecular formula of diazomethane can be determined by using the percentage composition by mass and the molar mass of the compound. In this case, the molecular formula is CH2N2. To draw the Lewis structure of diazomethane, start by placing the carbon atom in the center. Place a nitrogen atom on each side of the carbon atom, and then place a hydrogen atom bonded to each nitrogen atom. The formal charges of the atoms in diazomethane are as follows: carbon has a formal charge of 0, each nitrogen has a formal charge of +1, and each hydrogen has a formal charge of 0.

Diazomethane is not very stable because it readily evolves nitrogen gas (N2) when exposed to heat or light. This is due to the presence of the highly strained nitrogen-nitrogen triple bond in the compound, which is relatively weak and can easily break.

Answer 2

The molecular formula of diazomethane is CH₂N₂, and the main reason for its instability is precisely the fact that it can very easily evolve nitrogen, as nitrogen's triple bond is one of the strongest covalent bonds in nature, and the energy released in its formation is more than enough to compensate the energy lost in the breaking of C-N bonds. The Lewis structure of diazomethane with the formal charges is attached below.

To obtain the molecular formula of diazomethane, we can imagine that we have 100 g of it. Now we can calculate the number of moles (n) for each of the elements, using their respective masses (m) and molar masses (M = 12 g/mol for carbon, 1 g/mol for hydrogen, and 14 g/mol for nitrogen):

n = m/M

n(C) = 28.57 g / 12 g/mol

n(C) = 2.38 mol

n(H) = 4.80 g / 1 g/mol

n(H) = 4.80 mol

n(N) = 66.64 g / 14 g/mol

n(N) = 4.76 mol

We now divide each of these numbers with the smallest of them (2.38) to calculate the molar ratio of the elements:

carbon: 2.38 / 2.38 = 1

hydrogen: 4.80 / 2.38 = 2

nitrogen: 4.76 / 2.38 = 2

Now we use these numbers to get the empirical formula of diazomethane: CH₂N₂.

The molar mass of the empirical formula is:

12 g/mol + 2 * 1 g/mol + 2 * 14 g/mol = 42 g/mol

Since this value is equal to the molar mass given to us, that means that CH₂N₂ is also the molecular formula of diazomethane.