unit 4

Question 1

VSEPR theory?

Answer 1

valence shell electron pair repulsion. based on mutual repulsion between valence electron pairs surrounding an atom. electron pairs want to be as far apart as possible, the atoms surrounding the central atom adopt an arrangement that minimises this repulsion.

Question 2

repulsion?

Answer 2

repulsion between bonding pairs dictates geometry.

Question 3

simple molecular geometry?

Answer 3

2 bonds - linear
3 bonds - trigonal planar 
4 - tetrahedral 
5 - trigonal bipyramidal 
6 - octahedral

Question 4

2 bonds with 1 lone pair or 2 bonds with 2 lone pairs?

Answer 4

bent.

Question 5

4 bonds and 1 lone pair?

Answer 5

seesaw.

Question 6

3 bonds 2 lone pairs?

Answer 6

t-shaped.

Question 7

3 bonds 1 lone pair?

Answer 7

trigonal pyramidal.

Question 8

5 bonds 1 lone pair?

Answer 8

square pyramidal.

Question 9

2 bonds 3 lone pairs?

Answer 9

linear.

Question 10

4 bonds 2 lone pairs?

Answer 10

square planar.

Question 11

bond angles?

Answer 11

linear - 180
trigonal planar - 120
tetrahedral - 109.5
trigonal bipyramidal - axial 90, equatorial 120
octahedral - axial 90, equatorial 90

Question 12

hybridization?

Answer 12

the mixing of two or more orbitals to form a new set of hybrid orbitals.

Question 13

sigma bonds?

Answer 13

covalent bonds formed by orbitals overlapping end to end with the electron density concentration between the nuclei of the two atoms involved.

Question 14

pi bonds?

Answer 14

covalent bonds formed by sideways overlapping orbitals with electron density concentrated above or below the plane of the nuclei of the two atoms involved.

Question 15

bonds?

Answer 15

single bonds - 1 sigma
double - 1 sigma 1 pi
triple - 2 pi 1 sigma

Question 16

dipole moments?

Answer 16

the measure of the polarity of a polar covalent bond.

Question 17

intermolecular forces?

Answer 17

london dispersion forces, dipole dipole moments, hydrogen bonds, ion dipole, ionic bonds.

Question 18

intermolecular?

Answer 18

attractive forces between molecules (41kj to vaporize 1 mole of water)

Question 19

intramolecular?

Answer 19

hold atoms together in a molecule (930kj to break all O-H bonds in 1 mole of water).

Question 20

LDF’s?

Answer 20

attractive forces that arise as a result of temporary dipoles induced in atoms or molecules.

Question 21

dipole dipole forces?

Answer 21

attractive forces between polar molecules.

Question 22

hydrogen bonding?

Answer 22

special dipole dipole interaction between hydrogen atoms in a polar N-H, O-H or F-H bond.

Question 23

ion dipole?

Answer 23

attractive forces between an ion and a polar molecule.

Question 24

boyle’s law?

Answer 24

P1V1=P2V2

pressure and volume are inversely proportional.

Question 25

charles’ law?

Answer 25

V1/T1 = V2/T2

directly proportional.

Question 26

gay-lussac law?

Answer 26

P1/T1 = P2/T2

directly proportional.

Question 27

avogadro’s law?

Answer 27

V1/n1=V2/n2

directly proportional.

Question 28

ideal gas law?

Answer 28

PV=nRT

Question 29

ideal gas?

Answer 29

a hypothetical gas whose pressure-volume-temperature behaviour can be completely accounted for by an ideal gas equation.

Question 30

density of a gas?

Answer 30

d = PM/RT

Question 31

partial pressure?

Answer 31

pressure of each gas in a mixture is proportional to the number of moles and if each gas behaves ideally the total pressure of a mixture of gases is the sum of the partial pressures of the component gases.

Question 32

daltons law of partial pressures?

Answer 32

gas particles in a mixture behave independently and exert the same pressure in the mixture that they would exert if they were in the container alone.