Calculating the Number of Moles of HNC

Oct 13, 2025 by wbrum.org 117 views

Introduction

In chemistry, calculating the mass of a substance required to achieve a specific concentration in a solution is a crucial task. In this article, we will discuss how to calculate the mass of HNC (Hydrocyanic acid) that must be dissolved in water to obtain a 300cm^3 solution with a concentration of 0.6M. We will use the given atomic masses of H (1), C (12), and N (14) to perform the calculation.

Understanding the Problem

To solve this problem, we need to understand the concept of molarity (M) and the formula for calculating the mass of a substance required to achieve a specific concentration in a solution. Molarity is defined as the number of moles of a substance per liter of solution. The formula for calculating the mass of a substance is:

m = n x M x Molar Mass

where:

m = mass of the substance in grams
n = number of moles of the substance
M = molarity of the solution
Molar Mass = molecular weight of the substance

Calculating the Number of Moles of HNC

First, we need to calculate the number of moles of HNC required to achieve a concentration of 0.6M in a 300cm^3 solution. Since the solution is 300cm^3, we need to convert this volume to liters:

300cm^3 = 0.3L (since 1L = 1000cm^3)

Now, we can calculate the number of moles of HNC required:

n = M x V (in liters) = 0.6M x 0.3L = 0.18 mol

Calculating the Molar Mass of HNC

The molecular formula of HCN is H-C-N. To calculate the molar mass of HNC, we need to add the atomic masses of H, C, and N:

Molar Mass = Atomic Mass of H + Atomic Mass of C + Atomic Mass of N = 1 + 12 + 14 = 27 g/mol

Calculating the Mass of HNC Required

Now that we have the number of moles of HNC required and the molar mass of HNC, we can calculate the mass of HNC required:

m = n x Molar Mass = 0.18 mol x 27 g/mol = 4.86 g

Conclusion

In this article, we discussed how to calculate the mass of HNC required to achieve a concentration of 0.6M in a 300cm^3 solution. We used the given atomic masses of H, C, and N to perform the calculation. The results show that approximately 4.86g of HNC is required to achieve the desired concentration.

References

CRC Handbook of Chemistry and Physics, 97th Edition
IUPAC Compendium of Chemical Terminology, 2nd Edition

Frequently Asked Questions

Q: What is the molecular formula of HCN? A: The molecular formula of HCN is H-C-N.
Q: What is the molar mass of HNC? A: The molar mass of HNC is 27 g/mol.
Q: How many moles of HNC are required to achieve a concentration of 0.6M in a 300cm^3 solution? A: Approximately 0.18 mol of HNC is required to achieve the desired concentration.