Chapter 11 - Physical Properties and Chemical Reactivity!!

Question 1

boiling

Answer 1

liquid to gas phase change

Question 2

melting

Answer 2

solid to liquid phase change

Question 3

how does melting/boiling happen?

Answer 3

energy disrupts intermolecular forces present

Question 4

intermolecular forces def and different types

Answer 4

electrostatic forces that occur between atoms, ions, molecules

dipole - dipole, hydrogen bonding, london (dispersion) forces

Question 5

are covalent bonds broken in melting or boiling?

Answer 5

NO!!!

Question 6

solubility

Answer 6

the ability to form a solution with a substance

like dissolves like (ex non polar x non polar or polar x polar)

Question 7

what happens when a substance is dissolved in a liquid?

Answer 7

ions are separated and interact with solvent molecules.

ionic compound dissolves if the resulting intermolecular forces strong enough to overcome forces of attraction between ions

Question 8

dipole - dipole interaction

Answer 8

electrostatic attraction between partial positive charge one molecule and partial negative on other

higher boiling point than non polar, middle of strengths

can be attractive (opposite charges) or repulsive (same charges)

attractive results in greater coulombic force therefore stronger than repulsive

Question 9

hydrogen bond

Answer 9

dipole dipole interation between a hydrogen atom and N, O, or F (all very electronegative atoms)

the H-N H-O H-F bonds are SUPER polar and interact with other electronegative atoms to form a hydrogen bond

Strongest intermolecular force, but not as strong as covalent

Question 10

london force OR dispersion force OR london dispersion force

Answer 10

interactions between instantaneous dipoles, which could influence the distribution of atoms in adjacent atoms, resulting in induced dipole in the other atom and temporary electrostatic attraction between them

weaker of the intermolecular forces, could be more significant for large species

occurs in ALL atoms, ions, molecules etc

Question 11

polarizability

Answer 11

ease with which electron distribution in atom or molecule is distorted

larger atoms are more distortable because held less tightly by nucleus, therefore london dispersion forces are stronger and more energy is required to interupt intermolecular forces therefore higher boiling point

Question 12

van der waals forces

Answer 12

include dipole-dipole, hydrogen, and london forces

Question 13

what distance do dipole dipole interactions need based on r (distance between centres)

Answer 13

1/(r^3)

Question 14

what distance to london (dispersion) forces need based on r (distance between centres)

Answer 14

1/(r^6)

Question 15

how does hydrogen bonding in h2o affect the way ice floats on water?

Answer 15

when solid, water forms an ordered crystal structure in which hydrogen bonds are held still and are slightly further apart than in liquid water

this means ice is less dense than water and thus floats on top

Question 16

deprotation

Answer 16

removal of a proton (or hydron or hydrogen cation) from a Bronsted-Lowry acid

Question 16

deprotation

Answer 16

removal of a proton (or hydron or hydrogen cation) from a Bronsted-Lowry acid

Question 17

carboxylic acid group

Answer 17

organic acid containing a carboxyl group attached to an R-group

general formula A-COOH or R-CO2H

Question 18

ionic solid

Answer 18

consist of positive and negative atomic and/or molecular ions

strongly attracted to one another and form a crystal lattice

Question 19

coulombs law

Answer 19

energy of electrostatic attraction between a cation and an anion proportional to magnitude of two charges and inversely proportionate to distance between nuclei

E (squiggly proportionate symbolnot =) = [(n)*(m)]/dM-X

where n is charge of cation (+)
m is charge of anion (-)
dM-X is distance between ion centres

Question 20

lattice energy

Answer 20

energy required to convert one mole of crystalline solid into constituent ions at infinite separation in the gas phase (completely break intermolecular forces, sepeaate into ions)

units: kJ/mol

magnitude proportional to how strongly ions attract one another in ground state - stronger intermolecular forces, more energy required to break therefore greater lattice energy

Question 21

metallic bonding

Answer 21

electrons are able to move through a sample of metal because the difference between the ground state and excited state is very small\

interactions between atoms strong, so high melting and boiling point

conduct electricity, electrons can travel through metal wire in a circuit

Question 22

molecular solids

Answer 22

to exist as solid at room temp and pressure, intermolecular forces large enough to hold atoms relatively still

Question 23

network covalent solids

Answer 23

solids held together by bonds forming extended array

IMPORTANT very high melting and boiling points because covalent bonds must be broken, no other solid requires covalent bonds to be broken

polar and non polar molecular solids, atoms covalently bonded forming discrete molecules

ionic solids weaker dipole-dipole or london forces hold molecules together to form the solid

network covalent solids are network solids atoms held together by covalent bonds

Question 24

allotropic

Answer 24

elements which exist in more than one form in the same physical state

ex white phosphorus (a molecular solid) 4 covalently bonded phosphoruses as a tetrahedron, highly reactive
(^ reactive because 60 degree bond angles)

red phosphorus 4 phosphoruses in linear chains, one bond broken and too another, less strain, less reactive

black phosphorus, forms sheet structure, non as reactive, less strained

Question 25

condensation reaction

Answer 25

covalent bond formed with the release of a small molecule (ex water)

chemical change

essentially two larger molecules bonding, and each gives a couple atoms that form a smaller molecule as well - rxn of two molecules resulting in 2 molecules one being super small

Question 26

soap micelles

Answer 26

oils etc arent soluble in water

soap molecules oriented in micelle (made of multiple molecules), dirt etc trapped on inside of the micelle (by non -polar “tails” of soap molecule), charged heads of soap molecule allow micelle suspended in water

Question 27

triacyclglycerols

Answer 27

contain 3 ester functional groups - broken apart by strong base ex hydroxide (saponification)

3 fatty acids and a molecule of glycerol

each fatty acid has a carboxylic acid functional group, can combine w glycerol form ester functional groups

Question 28

what are lipids used for in people?

Answer 28

source of energy, energy storage, in cell membrane structure, as hormonal messengers

Question 29

2 common lipid types

Answer 29

tricylglycerols

steroids

Question 30

functional groups

Answer 30

covalently bonded groups w predictable chemical behaviour (ex ability to undergo chemical reactions

Question 31

chem reaction to form a triacylglycerol

Answer 31

dehydration

essentially removing an h from glycerol and on oh from fatty acids to form H2O and the glycerol and fatty acid combine

Question 32

fatty acid

Answer 32

straight chain of even number carbon atoms, hydrogen atoms along length and at one end and carboxyl group -cooh at other end (which makes it an acid)

vary in length and where double bonds are along the chain

in nature carbon chain length varies from 4 to 28

building blocks of fats

Question 33

ester

Answer 33

organic compound made by replacing hydrogen if an acid w an alkyl or other organic group

Question 34

monosaturated fats

Answer 34

fat containing one double bond

location influences properties

Question 35

polysaturated fats

Answer 35

contain more than one double bond

location influences physcial properties

Question 36

what does Si form?

Answer 36

network covalent solids

Question 37

what does SiO2 form?

Answer 37

network covalent solids

Question 38

what do diamond and graphite form? what are they?

Answer 38

network covalent solids

allotropes of carbon

Question 39

saturated vs unsaturated hydrocarbons

Answer 39

saturated contain only single carbon carbon bonds while unsaturated contain at least one double - unsaturated are more reactive

Question 40

copy and pasted word for word explanation of trends in saturated vs unsaturated fatty acids

Answer 40

saturated and has the highest melting point, mono-unsaturated (i.e., has one
C=C double bond) giving it a lower melting point, di-unsaturated lowest
melting point.

The tetrahedral bond angles on the sp3 hybridized carbons results in an overall molecular geometry for
saturated fatty acids, such as stearic acid, that is relatively linear (albeit “zig-zagging”). This allows the
fatty acid molecules to closely “stack” together in the solid. The close intermolecular interactions result
in relatively high melting points.
In contrast, the presence of one or more planar double bonds (sp2 hybridized carbons) in the
hydrocarbon chain of unsaturated fatty acids results in one or more “bends” in the molecule. These
molecules do not “stack” very well, thus weakening their intermolecular interactions. As a result, the
melting points are lower for unsaturated fatty acids, such as oleic acid (and even more so, linoleic acid)
than for saturated ones.