1.2 Structure and Bonding Flashcards
Fluorine has a greater attraction for bonding electrons than hydrogen. State the term used to describe the type of covalent bond in hydrogen fluoride.
Hydrogen bond occurs between molecules that have hydrogen (bonded to N, O or F)
This is because they are strongly electronegative.
Name a form of carbon
Graphite
State the term used to describe the structure of solid ionic compounds like lithium nitride
Explain how London dispersion forces arise.
They are formed as a result of electrostatic attraction between temporary dipoles and induced dipoles caused by the movement of electrons in molecules.
Explain fully why the London dispersion forces in sulfur are stronger than those in oxygen.
Explain fully why vitamin C is soluble in water.
Vitamin C molecule is polar due to its hydroxyl groups. Because it has a hydrogen bond (water) it is really polar.
Explain fully why the boiling points of the group 4 hydrides increase going down the group.
Intermolecular forces increase going down the group. London dispersion forces are broken between the molecules. The more electrons the stronger the LDFs.
Name the type of intermolecular force that is responsible for the anomalous boiling point of ammonia, NH3
Hydrogen bonding
Explain the difference in polarities of trichloromethane and tetrachloromethane molecules.
Trichloromethane is polar and tetrachloromethane is non polar. Trichloromethane has a permanent dipole and tetrachloromethane has no permanent dipole.
Explain why diatomic elements form non polar molecules.
State the name of the strongest type of intermolecular force found between hydrogen fluoride molecules and explain how this type of intermolecular force arises.
Explain fully why the boiling points increases from hydrogen chloride to hydrogen iodide.
Explain why the melting point of phosphorus, P4, is much higher than that of nitrogen, N2.
Stronger intermolecular forces between phosphorus compared with nitrogen. London dispersion forces are the intermolecular forces present. There are more electrons in P4 compared to N2.
Explain fully, in terms of structure and bonding, why silicon dioxide has a higher melting point.
Silicon dioxide is a covalent network. It requires high energy to break strong covalent bonds.
Explain fully why silicon oxide has a much higher melting point than silicon hydride.
In SiO2 covalent bonds are broken. In SiH4 LDFs are broken, covalent bonds need more energy to break intermolecular forces. So covalent bonds are stronger than LDFs.
Name the strongest type of intermolecular forces broken down when bromoethane, CH3CH2Br boils.
Suggest why hexane is used as a solvent, rather than water.
Hexane is a non polar solvent and water is a polar solvent
Give two reasons why coconut oil has a higher melting point than olive oil.
Coconut oil molecules can pack more closely together. The LDFs between the molecules in coconut oil are stronger than in olive oils.
Explain the difference in polarities of ammonia and trichloramine molecules.
Ammonia is polar and trichloramine is non - polar. Ammonia is more polar beacause it has a permanent dipole in the from hydrogen bonding resulting in a higher electronegativity. Trichloramine is less polar because it had LDFs.
Explain fully why the London dispersion forces in sulfur are stronger than those in oxygen.
Explain fully why carbon dioxide is much less soluble in water than sulfur dioxide is in water.
CO2 is a non polar molecule due to its linear shape of the molecule which cancels out the polarity molecule. SO2 has an angular shape and is a polar molecule due to the electronegativity difference between the two elements in the molecule which cancels. The more polar the molecule the higher the solubility in polar solvents like water is likely to be.
Explain fully why the boiling points of the halogens increase going down group 7. (2017)
Explain fully why, of these three chlorides, silicon tetrachloride is the most soluble in hexane.
Silicon nitride has a melting point of 1900 degrees and does not conduct electricity when molten.
