Calculate The Mass of N in 2.34 G of N2h4

Hydrazine (N2H4) is a chemical compound containing nitrogen and hydrogen. Calculating the mass of nitrogen in a given mass of hydrazine is a common stoichiometry problem. This guide explains how to perform this calculation, including the formula, assumptions, and interpretation of results.

How to Calculate the Mass of N in N2H4

To determine the mass of nitrogen (N) in a sample of hydrazine (N2H4), follow these steps:

Determine the molar mass of hydrazine (N2H4).
Calculate the moles of N2H4 in the given mass.
Use the mole ratio from the chemical formula to find the moles of nitrogen.
Convert the moles of nitrogen to mass.

The key assumption is that the sample is pure hydrazine with no impurities. The calculation uses the molar masses of nitrogen (14.007 g/mol) and hydrogen (1.008 g/mol).

Formula Used

The mass of nitrogen (m_N) in a sample of hydrazine (N2H4) can be calculated using the following formula:

m_N = (mass of N2H4 × molar mass of N) / molar mass of N2H4

Where:

mass of N2H4 = given mass of hydrazine
molar mass of N = 14.007 g/mol
molar mass of N2H4 = (2 × 14.007) + (4 × 1.008) = 32.052 g/mol

Worked Example

Let's calculate the mass of nitrogen in 2.34 grams of hydrazine:

Molar mass of N2H4 = (2 × 14.007) + (4 × 1.008) = 32.052 g/mol
Moles of N2H4 = mass / molar mass = 2.34 g / 32.052 g/mol ≈ 0.0730 mol
Moles of N = 2 × moles of N2H4 = 2 × 0.0730 ≈ 0.146 mol
Mass of N = moles × molar mass = 0.146 mol × 14.007 g/mol ≈ 2.04 g

Therefore, 2.34 grams of hydrazine contains approximately 2.04 grams of nitrogen.

Interpreting the Results

The result shows that nitrogen constitutes about 87.7% of the mass of hydrazine (2.04 g / 2.34 g). This is consistent with the chemical formula N2H4, which contains two nitrogen atoms and four hydrogen atoms.

Note: The calculation assumes pure hydrazine. If the sample contains impurities, the actual mass of nitrogen may differ. Always verify the purity of the sample when precise results are required.

Frequently Asked Questions

What is the molar mass of hydrazine (N2H4)?

The molar mass of N2H4 is approximately 32.052 g/mol, calculated as (2 × 14.007) + (4 × 1.008).

How do I calculate the mass of nitrogen in N2H4?

Use the formula: mass of N = (mass of N2H4 × molar mass of N) / molar mass of N2H4. For 2.34 g of N2H4, this gives approximately 2.04 g of nitrogen.

What percentage of hydrazine is nitrogen?

Nitrogen constitutes about 87.7% of the mass of hydrazine, based on the molar masses of the constituent elements.

Can I use this calculator for other hydrazine derivatives?

This calculator is specifically for pure hydrazine (N2H4). For other derivatives, you would need to adjust the formula based on the specific chemical structure.