Question

(question 1 continued) n₂ can react with h₂ to form the compound n₂h₄. (e) a sample of n₂h₄ has a mass of 25g. identify the numerical quantity that is needed to convert the number of grams of n₂h₄ to the number of moles of n₂h₄. (you do not need to do the actual calculation.) (f) the lewis electron - dot diagram of n₂h₄ is shown below. h—n—n—h | | h h (i) based on the lewis electron - dot diagrams of n₂ and n₂h₄, compare the length of the nitrogen - to - nitrogen bond in n₂ with the length of the nitrogen - to - nitrogen bond in n₂h₄. (ii) based on the lewis electron - dot diagrams of n₂ and n₂h₄, compare the strength of the nitrogen - to - nitrogen bond in n₂ with the strength of the nitrogen - to - nitrogen bond in n₂h₄. (iii) identify the hybridization of the n atoms in n₂h₄.

Explanation:

Step1: Recall mole - mass conversion formula

The formula to convert mass ($m$) to moles ($n$) is $n=\frac{m}{M}$, where $M$ is the molar mass. So for converting grams of $N_2H_4$ to moles, we need the molar mass of $N_2H_4$.

Step2: Analyze bond length in terms of bond order

The $N - N$ bond in $N_2$ is a triple - bond ($N\equiv N$), and in $N_2H_4$ is a single - bond ($N - N$). The higher the bond order, the shorter the bond length. So the nitrogen - to - nitrogen bond in $N_2$ is shorter than that in $N_2H_4$.

Step3: Analyze bond strength in terms of bond order

Bond strength is directly related to bond order. A triple - bond has a higher bond order than a single - bond. So the nitrogen - to - nitrogen bond in $N_2$ is stronger than that in $N_2H_4$.

Step4: Determine hybridization of N atoms in $N_2H_4$

Each N atom in $N_2H_4$ has 3 bonding pairs and 1 lone pair. Using the concept of hybridization, the steric number (sum of bonding pairs and lone pairs) of each N atom is 4. So the hybridization of N atoms in $N_2H_4$ is $sp^3$.

Answer:

(e) Molar mass of $N_2H_4$
(f)(i) The nitrogen - to - nitrogen bond in $N_2$ is shorter than that in $N_2H_4$.
(f)(ii) The nitrogen - to - nitrogen bond in $N_2$ is stronger than that in $N_2H_4$.
(f)(iii) $sp^3$