Ammonium Chloride is a white solid. When heated to 325 degrees C, it gives a vapor that is a mixture of ammonia and hydrogen chloride.
Suppose someone contends that the vapor consists of NH4Cl molecules rather than a mixture of NH3 and HCl. Could you decide between these alternatvie views on the basis of gas-density measurements? Explain.
To decide between the views that the vapor consists of NH4Cl molecules or a mixture of NH3 and HCl, you can use gas-density measurements. The basic idea behind gas-density measurements is that different molecules have different molar masses, so their densities will vary.
Here's how you can use gas-density measurements to determine the composition of the vapor:
1. Convert the given temperature of 325 degrees C to Kelvin by adding 273.15. So, 325 degrees C = 325 + 273.15 = 598.15 K.
2. Assume that a certain volume of the vapor is obtained and its mass is measured. Let's use the symbol 'V' to represent the volume of the vapor and 'm' to represent the mass of the vapor.
3. Calculate the density of the vapor using the formula: density = mass/volume.
4. Now, compare the measured density of the vapor with the known densities of NH4Cl, NH3, and HCl gases.
If the measured density of the vapor matches the density of NH4Cl, it would support the contention that the vapor consists of NH4Cl molecules. On the other hand, if the measured density matches the density of a mixture of NH3 and HCl, it would suggest that the vapor is indeed a mixture of NH3 and HCl.
NH4Cl has a molar mass of approximately 53.49 g/mol, NH3 has a molar mass of approximately 17.03 g/mol, and HCl has a molar mass of approximately 36.46 g/mol.
So, if the measured density matches the density of NH4Cl (around 53.49 g/mol), it would support the contention that the vapor consists of NH4Cl. However, if the measured density is closer to the density of a mixture of NH3 (around 17.03 g/mol) and HCl (around 36.46 g/mol), it would suggest that the vapor is a mixture rather than NH4Cl.
In conclusion, the comparison of gas-density measurements can help determine the composition of the vapor, whether it consists of NH4Cl molecules or is a mixture of NH3 and HCl.