R-ATCHE-8 model collision theory $[]\uparrow$ answer
R-ATCHE-9 industrial process
R-ATCHE-10 acid bases start
R-ATCHE-11 buffers
R-ATCHE-12 buffers 2
R-ATCHE-13 buffers 3
R-ATCHE-14 indicators
R-ATCHE-15 Acid and Base - Reactions
R-ATCHE-16 Volumetric Analysis (Titrations)
R-ATCHE-17 VA 2
R-ATCHE-18 indicator choice in a titration
R-ATCHE-19 calc for titration
R-ATCHE-20 calc for titration 2
R-ATCHE-21 organic start
R-ATCHE-22 carboxylic acids, aldehydes and ketones
R-ATCHE-23 continued organic (oxidation of alcohols, ketones)
R-ATCHE-24 esters!
R-ATCHE-25 experiment 31: reactivity of alcohols
R-ATCHE-26 amines amides
R-ATCHE-27 empirical formula - gas!
R-ATCHE-28 polymers! (addition)
R-ATCHE-29 polymers! two! (condensation)
R-ATCHE-30 amino acids
R-ATCHE-31 proteins
R-ATCHE-32 soap (synthesis section)
R-ATCHE-33 biodiesel
R-ATCHE-3(S) concluding acid base + titrations(volumetric analysis)
R-ATCHE-4(S) Ocean Equilibrium
R-ATCHE-5(S) volumetric analysis and pH calcs missing General Titrations Procedure subheading!!!!!!
R-ATCHE-6(S) titration procedure
R-ATCHE-7(S) organic
worship the datasheet data data data
Organic Chem Questions Organic Cheat sheet Empirical formula questions
The Acid base cheatsheet
H3PO4 - weak acid
H2PO4 - weak acid
HPO4 - weak base
PO4 - weak base
H2CO3 - weak acid
HCO3 - weak base
CO3 - weak base (but at the same time generally quite strong?? Wtf please ask mr norrie)
CH3COONH4 - NEUTRAL! K values for both acid/base reaction are 9.25 pka
HOWEVER, this can be applied to things that are arrhenius acid/base. for example, i could have 100g of NaOH but it wouldnt be basic until i put water
Pranav Question
a) in the first stage of the production of nitric acid, ammonia is reacted with oxygen to produce nitrogen monoxide.
A hot platinum catalyst is used. The reaction is highly exothermic, and the heat given out by the reaction is sufficient to maintain the temperature needed to give a fast rate.
The system is at equilibrium until t1 and then at t1, the volume of the vessel is reduced at constant temperature. Equilibrium is re-established at t2.
$4NH_{3} + 5O_{2} \rightleftharpoons 4NO + 6H_{2}O$ , $\Delta H<0$
Sketch the rate-time graph for the forward and reverse reactions to show the changes in rate until the return to equilibrium
b) Using "increase, decrease or no change" in the table below, identify the effect of reducing the volume of the mass and concentration of NH_3 and NO once equilibrium has been re-established.
NH3 | NO | |
---|---|---|
Mass | ||
Concentration |
c) The second stage involves the reaction of nitrogen monoxide with more oxygen to form nitrogen dioxide. $2NO + O_{2} \to 2NO_{2}$
At t0, 2.5 mol of NO and 1 mol of $O_{2}$ was injected into a 500mL container. At t1, equilibrium was re-established with only 1 mole of NO remaining.
Use this information to construct a detailed graph for how the concentrations of $NO_{2}$, $O_{2}$ and $NO_{2}$ varied between t0 and t1
"An unknown mass of $HCl$ was accidentally spilled into a swimming pool of volume $5.00\times10^6 L$ by a maintenance staff member. To determine the mass of $HCl$ dropped, the technician took a $22.10 mL$ solution of $HCl$ and titrated this solution with standardised $0.1210 molL$ $NaOH$ solution. The titration was carried out using a pH monitoring machine. The titration was stopped when $35.40mL$ of $NaOH$ has been added. At this point the pH of the resulting solution was measured to be exactly 9.7 as excess $NaOH$ had been added and thus the solution was now a consistent pink(as phenolphthalein indicator was used)."
a) Determine the concentration of $HCl$ in ppm that was present in the swimming pool after the mishap if the density of the poll solution is $1.318gmL^{-1}$.
$$\begin{align} [H^{+}] = 10^{-pH} = 10^{-9.7}=1.995\times 10^{-10} molL^{-1} \\ \text{Assume }25° C\text{, }\therefore K_{w}=[H^{+}][OH^{-}], \therefore [OH^{-} ] =\frac{1\times \times 10^{-14}}{1.995\times 10^{-10}}=5.01\times 10^{-5}molL^{-1} \\ n=cV, \therefore n(OH^{-}) = 5.01\times 10^{-5} \times 0.02210= 1.11\times 10^{-6}mol \\ n=CV, \therefore n(OH^{-} \text{ added}) = 0.1210\times 0.03540=4.28\times 10^{-3} mol\\ \therefore n(OH^{-} \text{reacted}) = n(OH^{-} \text{ added}) - n(OH^{-}) = 4.28\times 10^{-3} - 1.11\times 10^{-6} = 4.28 \times 10^{-3} mol \\ OH^{-} + HCl \to Cl^{-} + H_{2}O \\ \therefore \text{1:1 ratio, } n(HCl) = n(OH^{-}) = 4.28 \times 10^{-3}mol \\ \end{align} $$b) THe person carrying out the titration noticed that the pH metre recorded a sharp increase near the equivalence point but as the volume of $NaOH$ added increased and the solution colour remained pink, the pH maintained at a very high value and increased gradually. Explain these two observations with reference to the appropriate chemical principals. You may refer to the pH curve given.
(The pH curve given starts acidic and goes basic, equivalence is at neutral (7))
The pH is increasing.
Weak acids don't titrate any differently
Diprotic
Boiling melting, viscosity, look, colour, smell(?)
Revise IMF related to carboxylic acids.
Tartaric acid:
Malic acid:
Malic acid is a lot less able to dissolve in water, due to a reduced hydrogen bonding capability.
They are probably going to ask us for a hypothesis on this.
Make sure "If.. Then" is quantitiative.
i.e. "If TA of wine increased, concentration of tartaric acid has decreased(proportional to malic acid, maybe???!??!?)".
Independent variable
Dependent variable
Control variables
Accuracy: how close to true values
Precision: closeness of your measured values
Reliability: consistency of findings over time
Validity: whether it addresses what it intends to do (the aim of the experiment)
Revise systematic, random error, probably make a list of systematic, random error for titrations.
A $200mL$ sample of wine was diluted to $250mL$ of water. $25mL$ of the diluted wine was titrated against $0.085molL^{-1}$ NaOH with an average aliquot of $20.55mL$
Assuming tartaric acid is the only acid $\implies$ find its concentration in $gL^{-1}$ and comment on whether its dry or sweet
Recall that 7-8.5 is sweet, 6-7.5 is dry
Recall that tartaric acid is essentially the same as malic acid, but tartaric acid has extra -OH
Biofuels
made of biomass
renewable feedstocks
carbon neutral, NOT carbon negative
natural $\implies$ less toxic to humans
sulfur: literally none. petroleum based sulfur: acid rain time
"burn cleaner" $\implies$ less particulates
BAD: make $NO_{x}$, ruh roh
Green chemistry of bioethanol
random
green chemistry(ornot) of ethanol
random
starch
As length of hydrocarbon chain increases, $K_{a}$ of carboxylic acid decreases as $-OH$ bond becomes less polar, hence proton is less able to be donated