Some Chemistry Questions

Can anybody help me? :frown:

- Explain why the melting point of boron trichloride is much lower than that of Sodium Chloride.

- Bromine Gas has the formula Br². When a sample of bromine was analysed in the mass spectrometer, three peaks of m/e values 158, 160 and 162 were identified. Give the formulae of the species responsible for the peaks.

- Why is Carbon Dioxide a gas at room temperature, but silicon dioxide a solid with a very high melting temperature?

- What is the overall ionic equation for the reduction of Fe³± ions by iodide ions?

Thank you so much if you can help. I have been trying to figure these out all day.....

Reply 1

cobra

- Bromine Gas has the formula Br². When a sample of bromine was analysed in the mass spectrometer, three peaks of m/e values 158, 160 and 162 were identified. Give the formulae of the species responsible for the peaks.

Bromine has more than one isotope each with a different atomic mass

Reply 2

e-n-i-g-m-a

the intermolecular forces found in CO2 are weak van der wal forces which require less energy to be overcome. Silicon dioxide is a a macromolecule consisting of a network of strong covalent bonds whihc require a large amount of energy to be broken.

Reply 3

Erana

seaspray

- Explain why the melting point of boron trichloride is much lower than that of Sodium Chloride.

NaCl has a giant ionic lattice structure, whereas BCl₃ has a covalent molecular structure. Within NaCl there are strong electrostatic forces of attraction between oppositely charged ions, which require a lot of energy to overcome and break. Within BCl₃, there are only weak Van der Waals forces, which are easily broken. Hence less energy is needed to break the intermolecular bonds in BCl₃ than is needed to break the bonds in NaCl.