Block 2 Flashcards
Why is water wet?
Its a liquid due to its hydrogen bonding
What are 3 different intermolecular forces?
(London) dispersion forces, Van der Waals, Hydrogen bonding.
What are (London) dispersion forces?
The London dispersion force is the weakest intermolecular force. The London dispersion force is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles.
What are Van der Waals forces?
A distance-dependent interaction between atoms or molecules. Unlike ionic or covalent bonds, these attractions do not result from a chemical electronic bond; they are comparatively weak and therefore more susceptible to disturbance. The van der Waals force quickly vanishes at longer distances between interacting molecules.
What is hydrogen bonding?
A hydrogen bond is a partial intermolecular bonding interaction between a lone pair on an electron rich donor atom, particularly the second-row elements nitrogen, oxygen, or fluorine, and the antibonding orbital of a bond between hydrogen and a more electronegative atom or group.
What are electrostatic interactions?
Electrostatic interaction (van der Waals interaction): The attractive or repulsive interaction between objects having electric charges.
What are temporary dipoles?
Temporary dipoles are created when electrons, which are in constant movement around the nucleus, spontaneously come into close proximity. This uneven distribution of electrons can make one side of the atom more negatively charged than the other, thus creating a temporary dipole, even on a non-polar molecule.
What are permanent dipoles?
Permanent dipoles. These occur when two atoms in a molecule have substantially different electronegativity: One atom attracts electrons more than another, becoming more negative, while the other atom becomes more positive. A molecule with a permanent dipole moment is called a polar molecule.
Temperature is directly proportional to…?
The average speed (Kinetic energy) of all the particles in the material.
Changing a liquid to a gas is referred to as the…?
The enthalpy of vaporisation
What is enthalpy?
Enthalpy, a property of a thermodynamic system, is equal to the system’s internal energy plus the product of its pressure and volume
What is a non-polar molecule?
A molecule that is symmetrical and/or has no difference in electronegativity within its bonds.
What is a polar molecule?
A molecule that is non-symmetrical and has a difference in electronegativity within its bonds.
True or False? Hydrogen bonds have to be overcome before the water molecules can move faster and the temperature can increase.
True
How come metals can conduct electricity?
Metals conduct electricity because the electrons inside the metal are relatively free to move. So when electricity is through metals, electrons carry electricity and spread it all over the metal. The mobility of electrons is the reason why metals conduct electricity.
What is a solution?
A solution must be clear.
What is a solution?
Tiny particles of solute dispersed in a solvent. A solution must be clear.
What is an emulsion?
An emulsion is a mixture of two or more liquids that are normally immiscible (Cant be mixed or blended together)
What is a suspension?
In chemistry, a suspension is a heterogeneous mixture that contains solid particles sufficiently large for sedimentation
What are adhesive properties?
Adhesion is the ability of dissimilar molecules to stick together.
What are cohesive properties?
Cohesion is the ability of like molecules to stick together. Water is strongly cohesive
What is a Solvent?
The ‘thing’ that does the dissolving. (The larger amount)
What is a Solute?
The ‘thing’ that gets dissolved. Solids, liquids and gases can be dissolved. (The smaller amount)
What determines the strength of an ionic lattice?
How close the atoms are together.