Water Part 2 Flashcards
Define non-polar bonds.
When covalent bonds form between the same elements, the bond is non-polar as the electrons are shared equally.
Give an example of non-polar bonds.
In a molecule, such as hydrogen the electrons in the covalent bond are shared equally between the two identical hydrogen atoms.
Give an example of polar bonds.
Hydrogen chloride molecule is a polar bond, because the more electronegative chlorine atom attracts the electron of the bond more than the hydrogen atom. This makes the Cl atoms slightly negatively charged, and the H slightly positive. The bond is said to be polar because of the unequal charge distribution hence the name polar molecule.
Define Polar Molecule
Polar molecules are molecules with an overall unequal charge distribution.
Define dipole - dipole forces.
With polar molecules there is a greater attraction between molecules cause by the attraction between the slightly positive part on one molecule and the slightly negative part of a different molecule. Hence, this intermolecular force is called a dipole-dipole force.
Are all molecules with polar bond, polar? Give a reason why.
No, because sometimes the dipole of the polar bonds (the polarity) depends on the symmetry and the shape of the molecule. As the dipoles can cancel out due to the symmetry. E.g. C02 is a linear molecule O–C–O and the two dipoles cancel out, making it non-polar.
Define Polar Bonds.
Polar bonds are covalent bonds where the shared electrons are not shared equally.
Define dipole.
A structure with two charged ends . With a small positive charge at one end and an equal negative charge at the other end.
Why is the water molecule is a polar molecule?
The water molecule has two polar O-H bonds, the molecule is bent and the dipoles do not cancel, so waiter is a polar molecule.
Define intermolecular forces.
Weak attractive forces between separate molecules.
What are the three types of Intermolecular forces?
Dispersion forces
Dipole - Dipole forces
Hydrogen forces
Define dispersion forces.
Dispersion forces are caused by the attraction between the negatively charged electrons of one molecule and the positively charged nuclei of the atoms of another molecule. Forces between non-polar molecules e.g. Oxygen molecules.
Define hydrogen bonding.
This is a special type of dipole - dipole attraction between a slightly positive hydrogen atom in one molecule and the very electronegativity atom in another molecule.
