1a.) Define homologous series (2)
Share functional group, share general formula
(Therefore similar chemical reactions and add CH2 for each next in chain)
1bi.) What is the general formula of cycloalkanes? (1)
CnH2n
1bii.) Why does the boiling point increase down the group of cycloalkanes? (2)
Larger molecules down the group so more electrons, therefore stronger Van der Waals, therefore more energy to break apart molecules or same argument with surface contact.
1c.) What product do you get with the addition of bromine to cyclopropane? (1)
1,2 - dichloropropane
1d.) Shape and explanation for cycloalkane (2)
Tetrahedral – 4 bonding pairs, equal repulsion
1e.) Draw E/Z isomers of structural isomer of cyclobutane (1)
E-But-2-ene and Z-But-2-ene
1f.) Fill in equations for free radical substitution with Br2 and C6H12 (5)
Initiation - Br2 -> 2Br
Propagation - Br + C6H12 -> C6H11 + HBr
Br2 + C6H11 -> C6H11Br + Br
Termination – Br + Br -> Br2
C6H11 + C6H11 -> C12H22
C6H11+Br -> C6H11Br
1g.) How does the initiation step have homolytic bond fission? (1)
Covalent bond breaks and 1 e- to each Br (forms two radicals).
1h.) Give the equation for when C5H10Br2 forms. (1)
C6H12 + 2Br2 -> C6H10Br2 + 2HBr
What is the bond enthalpy of N-O bond? (3)
90 KJ/mol^-1
What is the atom economy of the reaction? (1)
Forty something I think (47?)
How can you increase the atom economy? (1)
Use LiBr or NaBr
What is the percentage yield of the reaction? (3)
88.x (forgot what the 3rd sf was)
What is the enthalpy change of this reaction? (4)
-38.4? (think this is what I got, was negative 30 something – though some argument on whether moles should have been multiplied, need to see question paper to confirm)
Draw the Boltzman energy distribution for lower temperature and state why rate decreases (or higher and increases maybe?) (4)
Lower temp has higher peak but by the end is closer to 0. The activation energy is fixed. More particles with more energy than activation so more successful collisions. Axes labelled as number of particles on y and energy on x.
What effect does decreasing pressure have on the rate? (2)
Lower pressure = fewer particles per unit volume, therefore less collisions per second so slower rate.
What else is needed for the dynamic equilibrium to be true? (1)
Rate of forward reaction = rate of backwards
How does pressure affect equilibrium? (1)
None – same moles of gas on both sides
How does increase in temp affect compound concentration (2)
More H2 and I2, less HI as position goes in endothermic direction, so left.
What is the equation for storing CO2 with metal oxide? (1)
CaO + CO2 -> CaCO3 (could have replaced calcium with other group 2 metal or balance equation if with group 1)
What is the activation energy of the reverse reaction? (1)
182
Enthalpy change with 336 dm^3 (2)
+63
Definition of enthalpy of formation with standard conditions defined. (3)
Change in heat energy content when 1 mole of a compound is formed from constituent elements in standard states – conditions = 298K and 100KPa
Equation for deltaH of formation, with state symbols. (2)
0.5N2(g) + 2O2(g) + 2H2(g) + 0.5Cl2(g) -> NH4ClO4(s)
Mechanism of COH3 ion with 1-bromobutane. (3)
Delta + on carbon, delta – on bromine. Minus on O. Arrow goes from pair of electrons or negative sign on oxygen to carbon atom and arrow goes from C-Br bond to Br.
What do you get when nucleophilic substitution happens with CH2COO- ion? (1)
Butyl ethanoate
How does rate change with C-I instead? (1)
Rate up, C-I bond weaker so less energy to break
Give another example of CCS. (1)
Store liquid CO2 undersea
Geological formations
Etc….
Catalytic converter equation (1)
2NO + 2CO -> N2 + 2CO2
2 factors on how CO2 affects greenhouse effect (2)
Concentration of CO2 in atmosphere
Amount of ir absorbed by C=O
Incineration of CH3Cl (1)
CH3Cl + 2O2 -> CO + CO2 + HCL + H2O (I put H2 though think it’s wrong, not certain though)
Polymerisation of CH3Cl equation (2)
n(CH3Cl) -> CH3Cl n
What is the product of methylbutene with reagent a? (1)
Br on each carbon atom of double bond
What is reagent a? (1)
Bromine water
State reagents and conditions for reagent B (1)
Can’t remember
Two structural isomers of the alcohol. (2)
Why does methylbutane not dissolve in water compared with alcohols (2)
No polar bonds which can form H bonds in methylalkane. Alcohol has OH, can form hydrogen bonds due to O.
Define structural isomerism. (1)
Same molecular, different displayed formula
Define stereoisomerism. (1)
Same structural formula, different arrangement of atoms in 3D space
Give equation, specific condition and temperature for fermentation. (2)
C6H12O6 -> 2C2H5OH + 2CO2
25-37 Celsius
anaerobic
Give the conditions, reagents, equations with structural formulae and colour change for oxidation of propan-1-ol. (6)
Colour change for both was orange to green
Distillation, heated K2Cr2O7 with acid catalyst, makes propanal:
CH3CH2CH2OH + [O] -> CH3CH2CHO + H2O
Reflux with heated K2Cr2O7 and acid catalyst makes propanoic acid:
CH3CH2CH2OH + 2[O] -> CH3CH2COOH + H2O
8a.) Formulae of B,C,D,E and F and Mr of B. (6)
Mr B = 74
B = butan-2-ol
C =
D = Propanoic acid (maybe ethanoic)
E and F = Water and 2-butyl propanoate (maybe ethanoate)
8b.) What is the empirical and molecular formula of G, what ions cause the peaks to arise at X and Y, what is the structure of G? (7)
e.f = C2H3O
m.f = C4H6O2
X = C3H5+, Y = COOH+
Structure was CH2C(CH3)COOH or CH2CH2CHCOOH
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