4. what mass of urea is produced from 9.0 liters of ammonia?
the reaction is 2nh3(g) + co2(g) → h2nconh2(g) + h2og)

12.07 g.

Explanation:

2NH₃(g) + CO₂(g) → H₂NCONH₂(g) + H₂O(g),

It is clear that 2.0 moles of NH₃ react with 1.0 mole of CO₂ to produce 1.0 mole of H₂NCONH₂ and 1.0 moles of H₂O.

At STP, 9.0 L of NH₃ react with an excess of CO₂ gas:

It is known that at STP: every 1.0 mol of any gas occupies 22.4 L.

using cross multiplication:

1.0 mol of NH₃ represents → 22.4 L.

??? mol of NH₃ represents → 9.0 L.

∴ 9.0 L of NH₃ represents = (1.0 mol)(9.0 L)/(22.4 L) = 0.4018 mol.

Using cross multiplication:

2.0 mol of NH₃ produce → 1.0 mol of H₂NCONH₂, from stichiometry.

0.4018 mol of NH₃ produce → ??? mol of H₂NCONH₂.

∴ The no. of moles of H₂NCONH₂ = (1.0 mol)(0.4018 mol)/(2.0 mol) = 0.201 mol.

mass = n * molar mass = (0.201 mol) * (60.06 g/mol) = 12.07 g.

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.