chemistry unit 3 and 4

What is a haloalkane?

An alkane with at least one halogen atom in place of a hydrogen atom. eg. chloro, bromo...

What is an alcohol?

A hydroxyl group (OH) that is attached to saturated carbons. the parent chain ends with 'ol'

what are the 3 groups of alcohols

primary secondary and tertiary

what is hydroxyl?

"Hydroxyl" refers to -OH

what is carbonyl?

refers to C=O

what is carboxyl?

"Carboxyl" refers to COOH (double bonded to an oxygen atom)

What is an aldehyde?

they contain oxygen at the end of a parent chain which is double bonded to a carbon. the carbon is always bonded to hydrogen. the name ends with 'al'

What are ketones?

they contain oxygen in the middle of a parent chain, double-bonded to carbon. the carbon is joined to 2 other carbons. the name ends with 'one'

carboxylic acids

the chain containing the COOH becomes the main chain. the name ends with 'oic' eg. butanoic.

what is an Amide?

they are derived from carboxylic acids. they are classified as primary, secondary or tertiary.

What is chromotography?

a technique for the separation of a mixture by passing it in solution or suspension through a medium in which the components move at different rates.

what are the phases of chromatography?

Mobile and stationary

What is the mobile phase?

a liquid or gas that carries the sample through the column

what is the stationary phase?

a solid to which the sample molecules absorb as they move through the column

What is size exclusion chromatography?

relies on porous beads; larger molecules elute first because they are not trapped in small pores. the ability of molecules to pass through pores in the stationary phases.

What is mass spectrometry?

it determines the molecular mass of a compound, and the isotopic composition of an element. Molecular ions are separated by their mass through a magnetic field and collected by a detector.

what is Infrared Spectroscopy?

determines the bonds and functional groups that are present or absent in a compound

open system

allows matter and energy to be exchanged with the surroundings.

closed system

allows only energy to be exchanged with surroundings.

Law of Conservation of Mass

in a chemical reaction, matter is neither created nor destroyed

Maxwell-Boltzmann distribution

Shows the distribution of the molecular energies in a gas at a constant temperature. The area under the curve indicates the total number of particles present.

Reversibility

physical changes are usually reversible but only some chemical reactions are reversible

What is dynamic equilibrium?

Equilibrium in a closed system where the reactions occur at exactly the same rate in each direction

What are catalysts?

a substance that increases the rate of a chemical reaction without participating in the reaction

Percentage yield

actual yield/theoretical yield x 100

Concentration

the amount of particles in a given volume

what effects equilibrium position?

temperature and concentration

How to change concentration

- add reactants/ products
- increase temp
- add inert gas

What is Le Chatelier's principle?

if you change the conditions of a reversible reaction at equilibrium, the system will try to counteract that change

pH

measure of concentration of hydrogen ions in a solution. tells us how acidic the solution is.

Equilibrium law

For the equilibrium aA+bB=cC+dD Kc=[C]^c[D]^d/[A]^a[B]^b

Exothermic

reactants have more energy

endothermic

products have more energy

monoprotic acid

an acid that can donate only one proton (hydrogen) to a base

polyprotic acid

an acid that can donate more than one proton per molecule

strong acids and bases

completely dissociate in water

redox reactions

When there is a transfer of one or more electrons from one reactant to another.

proton donor

a substance that can donate H+ (hydrogen ions)

strong acid vs weak acid

Strong-dissociates completely / more readily, releases more H+, weak acid does not, partly dissociates (same with strong and weak bases)

oxidation

when substances combine with oxygen

reduction

when substances give up oxygen

conservation of charge

The law that states that charges are neither created nor destroyed but only transferred from one material to another.

what is an anode in a galvanic cell

where oxidation occurs (negative charged)

what is a cathode in galvanic cell

where reduction occurs (positive charged)

which way do electrons flow in galvanic cell?

from anode to cathode

What is a fuel cell

a device that produces electricity combining hydrogen and oxygen without combustion

what is electrolysis?

the process where electric current is used to bring about a redox reaction when it doesn't occur spontaneously.

what is an electrolyte?

substance that conducts electricity when dissolved in water

What is brōnstead lowery

states that acids are any species that donates protons and bases are any species that accepts protons

end point

the point in a titration at which an indicator changes color

equivilance point

when chemicals have reacted according to the molar ratio

boiling / melting point of hydrocarbons

they have the lowest melting and boiling points because they only have hydrogen and carbon atoms joined by non polar bonds

branched alkanes have lower boiling points than straight chains

Hydrocarbon solubility

they are not soluble in water because they are non polar

melting/boiling point of alcohols

is significantly higher than hydrocarbons, because of the hydrogen bonding. when there is more hydroxyl groups boiling point is higher

melting/ boiling points of aldehydes and ketones

the melting and boiling points are lower because there is no hydroxyl functional groups. they are more volatile than alcohols. the melting and boiling points are still higher than hydrocarbons.

Solubility of Ketones and Aldehydes

Small aldehydes and ketones are soluble in water
The longer the carbon chains, the less soluble they become

melting/ boiling point for carboxylic acids

they can hydrogen bond, and therefore they have higher melting and boiling points (higher than alcohol)

define substitution recation

when a substituent is replaced by another

Why is carbon susceptible to substitution reactions

because of its polarity (polar bonds)

Define esterification

The reaction of an alcohol with a carboxylic acid to produce an ester and water.

What is a condensation reaction?

A reaction in which two molecules combine to form a larger molecule, producing H2O as a by product

What is an amide synthesis reaction?

they are synthesised from carboxylic acids and amines

what is polymerisation

The chemical process during which hydrocarbon monomers are joined to make longer strings of molecules (polymers). addition of alkene monomers to form polymers

What is a homologous series?

A family of organic compounds that have the same functional group, similar chemical properties and the same general formula, but differ by 1 carbon atom

what is addition and elimination

addition occurs when atoms add across a double or triple bond in a hydrocarbon

what are the types of addition?

hydrogenation, halogenation, hydrohalogenation, hydration, polymerisation

what is hydrogenation

the addition of hydrogen to each carbon atom, converting alkenes to alkanes

What is halogenation?

the addition of a halogen to each carbon atom, converting alkenes to haloalkanes

What is hydrohalogenation?

The addition of HCl or HBr, converts alkenes to haloalkanes

What is Markovnikov's rule?

the carbon with the most H atoms gets the H

What is hydration?

addition of H2O, converts alkenes to alcohol

what is polymerisation

addition of alkene monomers to form polymers

What is the Haber-Bosch process?

an industrial process for producing ammonia from nitrogen and hydrogen, using an iron catalyst at high temperature and pressure.

what is the contact process

an industrial process used to make Sulfur dioxide

Define biodegradation

the breakdown of a substance into micro-organisms

what are the 3 stages of the contact process

S + O2 = SO2
2SO2 + O2 = 2SO3
SO3 + H2O = H2SO4

what is the difference between a reagent and a reactant

a reagent is used to detect something in a reaction (eg colour change) and a reactant is a molecule participating in the reaction.

What is a steroisomer?

compounds that have the same molecular formula and structural formula but a different arrangement of atoms in space

geometrical isomers

stereoisomers that have different arrangements of atoms around a rigid double bond. they can be cis or trans

Cis isomers vs trans isomers

Cis - Same Side of the double bond
Trans - Opposite of the double bond

Enantiomers

2 compounds that have the same atoms and bonding but a different arrangement of four substituents around a carbon atom

electrolysis

electrical energy is passed into a cell, using a power source, resulting int he reversal of spontaneous redox reactions

self ionisation of water

the reaction in which a water molecule loses a hydrogen ion to become a hydroxide ion and the hydrogen ion immediately reacts with another water molecule to form a hydronium

The Kw constant

is the constant for the self ionisation of water