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60 Cards in this Set
- Front
- Back
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Steroisomers
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Same molecular formula but same structural formula
but different spatial arrangement of atoms |
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Structural isomerism
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Same molecular formula but different structural formula
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Homologous series
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A series of organic compounds having the same functional group and each member differs from the next by CH2
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Functional group
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A group of atoms responsible for the characteristic reactions of a compound
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What is E/Z and trans/cis
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Entegegen zusammen
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What do you need to mention at all times when you
mention E/Z groups? |
Double bonds restricts rotation
each C in the C=C double bond bonded to 2 different atoms or groups |
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Curly arrow
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Curly arrows show the movement of electron pairs
Tails need to point at the bond or lone pair Head if next to the atom form a bonding pair If head is pointed at the atom it forms a lone pair |
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Percentage yield
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Acutal/theoretical x100
Percentage yield is a measure of conversion of reactants into products |
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Atom economy
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Molecular mass of desired product/molecular mass of all products x100
Atom economy considers all the products form a reaction |
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Explain the Boiling points/volatility of Alcohols
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Alcohols have high boiling points and relatively high volatility compared to alaknes
Alcohols have hydrogen bonds and Van der waals forces acting between molecules.Therefore more energy is required to break the hydrogen bonds If you get asked to compare two ethanol's just mention 2 hydroxides |
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Explain the Solubility of alcohols
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Smaller molecules of alcohol are way more soluble then larger molecules of alcohol.This is due to hydroxides forming hydrogen bonds with the water.
In larger molecules the rest of the chain is not attracted by the water. |
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How do you classify alcohols
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Primary
-The carbon that is bonded with OH is also bonded to 1 Secondary Same as above but the carbon is bonded to 2 Tertiary Carbon is bonded to 3 |
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How do I produce alcohols
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Either through fermentation or hydrating ethene
C6H12O6-->2C2H5OH+2CO2 for fermentation and C2H4 +H2O -->C2H5OH |
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How would you answer a big question on producing alcohols?
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Points to make-
-Mention that fermentation is renewable and hydrating ethene is non- renewable -Mention that more energy is required to start the hydration reaction -Hydrating ethene has a 100% economy where as fermentation has CO2 as a waste product |
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Equations for working out alkenes and alkanes
CnH2n+2 for alkenes CnH2n for alaknes CnH2n for cyclos be careful not think that they are an alkene |
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Equation for working out an alcohol
CnH2n+1OH |
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When a question asks why cyclos are produced mention that they reduce engine knocking
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Fractional distillation points to make dependant on question:
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-hydrocarbons have different boiling points.
-The bigger the molecule the stronger the VdW force. -The column gets cooler as you go to the top -The column produce smaller molecules at the top larger one stay at the bottom due to (see dash 2 @ top) -Molecules at the top are much easier to ignite (don't mention flammable) -Volatility (how easy it forms into a gas) increases as you go to the top -Viscosity decreases as you go down -The chain length decreases |
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Complete incomplete combustion from GCSE
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Reminder:
CH4+O2-->CO2 + H2O (complete combustion = (blue flame) CH4+O2 (lack of oxygen)--->CO + C (sut/silt) +H2O (yellow/orange flame when burning) |
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In the exam they might use Alkynes! instead of alkenes.There is no difference but the equation is CnH2n-2 not +2
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What is Electrophilic addition?
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A type of addition reaction in which an electrophile is attracted to an electron-rich centre or atom,where it accepts a pair of electrons to form a new covalent bond.
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radical
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a species with an unpaired electron
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Homolytic fisson
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a covalent bond breaking with both electrons from the bonding pair atoms going to each atom
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Hetrolytic fission
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A covalent bond breaking with both electrons only going to one atom.Forming a positive and negative ion.
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Enthalpy change (delta H)
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Change in heat constant at constant pressure
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Standard condition
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298 K or 25 temp. and 1 mole of solution
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Standard enthalpy change of formation
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Enthalpy change when 1 mole of a substances is formed form its constituent elements with all reactants and products in standard states under standard conditions
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Standard enthalpy change of reaction
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The enthalpy of change that accompanies a reaction in the molar quantities expressed in a chemical equation where the reactants and products are in standard states and standard conditions.
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Standard enthalpy change of combustion
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Enthalpy change when 1 mole of a substances is reacted by being completely burned in oxygen for combustion, with all reactants and products in standard states under standard conditions
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What is nucleophilic substitution
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A type of substitution reaction in which a nucleophile is attracted to an electron deficient centre or atom, where it donates a pair of electrons.
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Average bond enthalpy (might be refereed to as just bond enthalpy)
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The average enthalpy change when one mole of of given type of bond is broken, homolytic fission, in the molecules of a gaseous species.
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Markovnikov's rule states that when addition reaction takes place the Bromine for example goes to the more stable side due to the molecule being unsymmetrical.If symmetrical the Br would go to both sides.
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Examiners might trick you with a dicarboxyl acids just be careful when interpreting a question that the empirical formula doesn't screw you over.Just double it to sort it or draw it out if your really stuck.
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What is the boltzman's distribution principle?
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A graph that shows how many molecules are above or below the average energy.
When the temp. decreases the line moves above the "normal line" and to the right behind the "normal line" When temp. increases the line moves below the average line and and further out the the right side of the line indicating that more molecules are in the activation energy zone. A catalyst will only move the Eact further up the line.A catalyst only provides different path for molecules to go and decreases the Eact overall. |
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A carbon chain has what bond angels?
-4 bonds -3 bonds |
4= 109.5 tetrahedral shaped molecule (when no double bonds are present)
3= 120 Trigonal planar shaped molecule (only when double bond is present) |
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The term for acitation energy
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The minimum amount of energy required for reactants to react.
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Hess' Law?
(and how would you calculate it) |
The enthalpy change of a chemical equation is the same, independent of the route to achieve the products.
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Mass spectrum how to find the ions and more?
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Look at the total mass of the compound next look at the mass that has the highest abundance (usually 100%) and calculate the mass of element s until the highest abundance is met.
Eg. a compound with a mass of 60 and the highest abundance at 31 m/z what part of the molecule is it? CH2OH=12+1+1+16+1=31 |
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Ethene can be widely used as what?
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dichloroethane used as paint remover
Ethane 1,2 diol used for antifreeze Ethanoic acid used for vinegars |
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Examiners twists they might use to confuse polymerisation.
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-they might put symbols instead of H
-They might put a chain number on for example a chain of 3000 which would be wrong to put as n just divide it by the number of carbons -they might put two types of polymers on and ask you to connect them eg. C2H4 and C2F3CH3= both connected with the second molecule as m not n |
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How would I draw the bonds on C-C molecule
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Draw the two C's
Draw the area of electron density and call it sigma Draw 2 more electron dense areas above and below the sigma bond and call them pi bonds pi for p orbitals and sigma for s orbitals. |
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They might mix an addition reaction with a precipitation reaction what are the key points of ppt?
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Add Silver nitrate (AgNO3)
Forms a white(Cl-), cream (Br-) or yellow (I-) precipitate Cl precipitate dissolves in Dilute NH3 Br dissolves in conc. NH3 I does not dissolve in any NH3 |
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What is hydrogenation?
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Adding hydrogen to an already existing C=C double bond and make it single bonded.
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Define volatilaty
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volatility is the ease of evaporation of a molecule
high boiling point = low volatility low boiling point = high volatility |
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define intermolecular bonds
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The forces of attraction between molecules
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How are alkoxides formed from alcohols?
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using a group 1 element (mostly) attach it to the O of the alcohol and remove the H
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What is the (element) used for in later processes?
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The element is used for feedstock in other reactions, reactions such as :
(the reactions the element is associated with) |
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Define the term Catalyst
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It is a compound or atom that is able to lower the activation energy of a reaction ,by creating a different pathway of reaction, and not use itself up.
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what is the difference between an ester and a carboxylic acid what functional group do the posses?
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Carboxylic acids: have Double bond O, single bond O and H molecules
Esters:Have a double bond O, and a single bond O attached to another part of C. |
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What 4 things can I make through the process of evaporating an alcohol through a condenser (leibig tube)?
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1)Refluxing causes a carboxylic acid to form when primary,when secondary a ketone is formed.
2)When distilling |
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What is hydrolysis?
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Hydrolysis is the addition of water of a molecule they both form corresponding molecules
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Describe the Equilibria position change during these conditions:
When temperature increases/decreased? When a higher and lower pressure is applied? When a catalyst is added? When the container volume is decreased? When a product or reactant is removed? |
-Temperature when increased cause the equilibria (eq) to move relative to the forward or backward reaction through the endothermic way.When decreased the eq will move to through the exothermic way.(examiners will give you clues which way is exo and which way is endo for example they will give you a enthalpy change number)
-A higher pressure forces the equlibira to move to the point of lower pressure in atoms it is the side with the least amount of moles that will be the lower pressure. -A catalyst has no effect on eq but it increases the rate of the reaction -Decreasing container volume is like decreasing pressure. -The eq will move to side of were the molecule or atom has been removed. |
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Why do factory not use a high pressure and temperature to get the best yield?
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They do not use higher pressure due to safety regulations and cost.
-Higher temperature again contradicts with safety and if temperature is to low, the reaction slows due to Acitvation energy not being high enough to react. -Instead companies use a moderate temperature and pressure to regulate equilibrium reactions to their favour. |
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State the Le Chatelier's principle?
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When a system in dynamic equilibrium is subjected to a change, the position of the equilibrium will shift to minimise the change.
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How do I achieve a dynamic equilibria?
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When the rate of the forward and backward reaction stays the same and does not move due to change.Or the pressure remains the same.When a reaction goes deq the rate of the forward reaction first speeds up before balancing to an equal.
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How does Ozone deplete in the atmosphere?
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Cl reacts with O3 makes ClO and O2
ClO and O react inroder to form O2 overall the reaction is O3+O=2O2 |
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How can I look for fragments in mass spectrometry graph? and what are the important features?
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-Find the total weight (always on the right)
-look for the highest abundance -divide the total weight by 14 (remove any functional groups) -find the fragment that equals the highest abundance and put + at the end as in every spectrometry an electron is removed. |
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Methods of carbon capture?
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Injecting CO2 into the ocean
Reacting them with metal oxides |
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Why are catalyst useful other than cost?
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-Lower activation energy required to start the reaction (lower temperatures)
-Increase in atom economy as less waste is made |
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Describe the stages of the catalytic converter reaction?
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-Molecules are adsorbed not absorbed
-the bonds are weakened between molecules decreasing activation energy -The molecules are then desorbed as products. |
