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What is extraction?<div><i>Choosing a solvent which selectively dissolves a particular&nbsp;</i><i>component</i></div>
What property does Solvent extraction exploit?<div>Solvent extraction exploits the fact that a solute may show the greatest difference&nbsp;in solubility between two solvents that are immiscible. When given the chance to&nbsp;dissolve in both, the solute becomes unequally distributed between the two, known as&nbsp;partition.</div>
How can solvents be separated with a separating funnel?The funnel is shaken, where since the two solvents are immiscible they will hence form two distinct phases.
What does solvent extraction require?<div>two immiscible solvents&nbsp;in which the required&nbsp;solute has very different&nbsp;solubilities.</div>
State the order of functional groups in increasing polarity and decreasing volatility?<div>amide &gt; carboxyl &gt; hydroxyl &gt; ketone &gt; aldehyde &gt; amino &gt; ester &gt; ether</div>
What is Fractional Distillation?<div>Fractional distillation is a separation technique which exploits differences in volatility through the use of a fractionating column.&nbsp; The process results in fractions, each of which contains a mixture of liquids which boil within a narrow temperature range.</div>
What is fractional distillation used for?<div>Fractional distillation is used in the isolation of drug products from liquid mixtures,&nbsp;and as part of the process used to separate chemical feed-stock, such as phenols and&nbsp;toluene, used in the synthesis of many drugs.</div>
What is the mole fraction?"<div>The mole fraction of a substance, shown with the symbol&nbsp;<b style=""color: rgb(31, 31, 31); background-color: rgb(255, 255, 255);"">Χ&nbsp;</b>refers to the fraction of the moles of the substance in a mixture</div>"
What is the vapour pressure?"<div>The vapour pressure is the pressure exerted by a vapour in equilibrium with its liquid&nbsp;at a given temperature in a closed system.&nbsp;&nbsp;</div><div><img src=""Screenshot 2024-09-13 at 1.39.54 PM.png""><br></div>"
What is Raoult's Law?<div>This states that the vapour pressure of a volatile substance in a solution is equal to the&nbsp;vapour pressure of the pure substance multiplied by its mole fraction in the solution.</div>
What is the formula to calculate total Vapour Pressure (P)?P_total&nbsp;= P_A&nbsp;+ P_B&nbsp;
What is the formula to calculate the vapour pressure using the vapour pressure of a pure substance (P^o)?P_A&nbsp;= P^o_A&nbsp;x X_A&nbsp;and P_B&nbsp;= P^o_B&nbsp;x X_B<br>P_total&nbsp;= P^o_A&nbsp;x X_A&nbsp;+ P^o_B&nbsp;x X_B
What is the vapour pressure of a solution of two liquids dependent on? What does this only occur in?"<div>the vapour pressure of a solution of two liquids depends on the vapour</div>
<div>pressures and proportion of each liquid present. The relationship applies only to&nbsp;so-called ideal solutions, those which contain fully miscible liquids.</div>"
Explain how Raoult's Law is used in Fractional Distillation<div>When a solution boils, it&nbsp;produces a vapour which is&nbsp;enriched in its more volatile&nbsp;component. When that vapour is collected, it condenses to form&nbsp;a solution which is also enriched&nbsp;in the more volatile component.&nbsp;&nbsp;By repeating the cycle of&nbsp;boiling and condensation, more&nbsp;and more separation of the&nbsp;components can be achieved.</div>
When does a solution boil?<div>A solution boils when its total vapour&nbsp;pressure reaches the external pressure</div>
What happens to boiling point up the fractionating column?Temperature decreases up the column, hence mixtures boiled at higher fractions having a lower boiling points of mixture.
How does a fractionating column function?<div>The surface&nbsp;area inside the column is increased by the presence of glass beads or glass projections.&nbsp;&nbsp;As the solution boils, vapour rises up the column until it condenses and falls back&nbsp;down. This vapour is then reboiled by ascending vapour, and the process repeats. The&nbsp;temperature decreases as the vapour rises up the column, allowing for a succession&nbsp;of boil–condense cycles. Eventually, the vapour exiting the flask is collected and&nbsp;condensed to form a liquid enriched in the more volatile component.</div>
What are Steroids??<div>Steroids are lipids with a structure consisting of four fused rings, known as a steroidal&nbsp;backbone</div>
Explain the use of Anabolic Steroids as performance enhancers<div><ul><li>Male steroid&nbsp;hormones are collectively called androgens, of which testosterone is the most&nbsp;important.&nbsp;</li><li>These hormones are known as anabolic steroids, due to their role in&nbsp;promoting tissue growth, especially of muscles.&nbsp;</li><li>They have been used as performance enhancing&nbsp;drugs by athletes in sports such as weight-lifting and cycling, as they&nbsp;can increase strength and endurance.&nbsp;</li><li>Anabolic steroids are usually synthesized from&nbsp;testosterone, and include drugs such as nandrolone, stanozolol, and furazabol.</li></ul></div>
Why are anabolic steroids banned?<div><ul><li>These compounds are toxic to the liver and can be associated with an&nbsp;increased risk of cancer and heart problems.&nbsp;</li><li>They also disturb the hormone balance in&nbsp;the body, causing changes in secondary sexual characteristics such as hair distribution&nbsp;and risks to fertility</li></ul></div>
What is the most common method used for detection of steroids in blood and urine samples, and state what each component doesThe most common method is gas chromatography - mass spectrometry<br><ul><li>Gas chromatography: separates chemical mixture into pure chemicals</li><li>Mass spectroscopy: Identifies and quantifies the components.</li></ul>
Describe the procedure for gas chromatography<ul><li>Useful technique for separating and identifying components of a mixture</li><li>Basic principle is that components have different affinities for two phases. stationary phase and mobile phase.</li><ul><li>Stationary Phase - microscopic layer of non-volatile liquid, usally a polymer, coated on the walls of an inert solid support</li><li>Mobile phase - an inert carrier gas, such as helium</li></ul></ul>
How is separation of components in gas-chromatography determined?<ul><li>Based on different rates at which they move through instrument</li><li>Rates differ according to the boiling points and solubilities of each component, these determine relative associations of the molecules with the liquid and gas phases.</li><li>Components thus partition themselves between the two phases.&nbsp; Molecules which spend more time in the gas phase move more quickly, while those with higher boiling points and greater solubility in liquid move slower.</li></ul>
Describe how gas chromatography is carried out?<ul><li>Sample introduced into instrument by injection then heated to vaporisation</li><li>The gas is mixed with the inert carrier gas and passed into the column</li><li>Temperature in the column is controlled and is typically lower than initial temperature, so that some of the components condense and may dissolve in the liquid phase on the walls of the column.</li><li>Depending on how they partition themselves between the two phases, components of mixture are eluted at specific intervals of time, known as retention time (more volatile components are eluted quicker, shorter retention time)</li><li>A detector is used to record passage of each compound as a peak, and the area under the peak is a measure of its concentration relative to a known standard.</li></ul>
Describe why Ethanol can affect the body so quickly<ul><li>OH group forms hydrogen bonds with water, and so can quickly pass from the gut to the blood and circulate to all parts of the body.</li></ul>
What does Ethanol act as?<ul><li>Depressant</li><li>Decreases the activity of the central nervous system, causing short-term changes in behaviour and long-term dependency.</li></ul>
Why do countries set legal limits for ethanol concentrations?<ul><li>Person whose judgement is changed by presence of ethanol in blood is said to be impaired, which is a potentially dangerous condition.</li></ul>
What is the blood alcohol concentration measured in?milligrams of ethanol per cm³&nbsp;of blood&nbsp;
Why can ethanol be detected in the breath?"<ul><li>Ethanol is volatile, and hence establishes equilibrium in the lungs between solution in the blood and gas, released in exhaled breath.</li></ul><div><img src=""Screenshot 2024-09-13 at 2.14.23 PM.png""><br></div>"
What are breathalysers?<ul><li>Instruments that measure ethanol concentration in a sample of breath and convert it into blood alcohol concentrations</li></ul>
Describe and explain the technique used for the detection of ethanol in the breath&nbsp;"<div><b>Breathalyzer:&nbsp;</b></div><b>
</b><div>+ The roadside breathalyzer test uses acidified potassium dichromate(VI) which reacts with any ethanol present in the breath and converts it to ethanoic acid.&nbsp;</div>
<div>+ Potassium dichromate is reduced while ethanol is oxidized.&nbsp;</div>
<div>+ Color of solution changes from orange to green due to the presence of Cr3+ ion.&nbsp;</div>"
Write out the half reactions and the full redox reaction in breathalysers"<img src=""Screenshot 2024-09-13 at 2.16.39 PM.png"">"
Describe how mixtures are separated with fractional distillation<ul><li>continuous evaporation and condensation occurs</li><li>increased surface area in column helps condensation, where temperature decreases up the fractionating column.</li><li>liquids therefore condense at different heights</li><li>most volatile liquid is collected first</li><li>fractions/liquids collected in order of boiling point/volatility</li></ul>
Describe how gas chromatography enables the components of urine to be analysed<ul><li><div>«components have» different affinities for/partition between 2 phases/mobile and stationary phase&nbsp;&nbsp;</div></li><li><div>move at different rates through instrument and have different retention times</div></li></ul>
<div>Some mild analgesics contain a solid mixture of acidic aspirin and a non-acidic organic&nbsp;chemical of similar polarity to asprin.&nbsp; Discuss how acid-base properties and the process of solvent extraction can be used to&nbsp;separate aspirin from the mixture.</div>"<ul><li><div style=""display: inline !important;"">dissolve compounds in an organic solvent</div></li><li>add NaOH(aq)/OH^–(aq) «to the mixture» to convert aspirin to its water soluble salt</li><li>separate the two «immiscible» layers</li><li>convert salt «in aqueous layer» back to aspirin by reacting with acid/H⁺</li><li>«evaporate solvents and dry»</li></ul>"
<div>The pharmaceutical industry is one of the largest producers of waste solvents.&nbsp; State a green solution to the problem of organic solvent waste.</div><ul><li>«use of» alternative solvents such as supercritical/liquid CO₂<br></li><li>use of water «as solvent»<br></li><li>solvent-free reactions «for example, polymerization of propene»<br></li><li>solid-state chemistry<br></li><li><div>recycle «waste» solvents</div></li><li>catalysis that leads to better/higher yield<br></li><li><div>reducing number of steps</div></li></ul>
"<span style=""color: rgb(63, 63, 63); background-color: rgb(247, 247, 247);"">Explain how the concentration of ethanol in a sample of breath can be determined using a fuel cell breathalyser.</span>""<ul><li><span style=""color: rgb(63, 63, 63); background-color: rgb(247, 247, 247);"">ethanol is oxidized «to ethanoic acid»</span><br></li><li><span style=""color: rgb(63, 63, 63); background-color: rgb(247, 247, 247);""><div>electrons are released which pass through an external circuit</div></span></li><li><div>current/potential proportional to concentration «of ethanol»<br></div></li><li><div><span style=""color: rgb(63, 63, 63); background-color: rgb(247, 247, 247);"">current compared to a reference «to determine concentration»</span><br></div></li></ul>"
"<font color=""#3f3f3f""><span style=""background-color: rgb(247, 247, 247);"">How can fractional distillation be used to separate two different compounds?</span></font>""<ul><li>two compounds have different strengths of intermolecular forces and thus have different boiling points</li><li><span style=""color: rgb(63, 63, 63); background-color: rgb(247, 247, 247);"">temperature in&nbsp;</span><strong>«</strong><span style=""color: rgb(63, 63, 63); background-color: rgb(247, 247, 247);"">fractionating</span><strong>»&nbsp;</strong><span style=""color: rgb(63, 63, 63); background-color: rgb(247, 247, 247);"">column decreases upwards</span><br></li><li><span style=""color: rgb(63, 63, 63); background-color: rgb(247, 247, 247);""><strong>«</strong>components<strong>»&nbsp;</strong>condense at different temperatures/heights<br></span></li></ul>"
"<span style=""color: rgb(63, 63, 63); background-color: rgb(255, 255, 255);"">Explain how redox chemistry is used to measure the ethanol concentration in a breathalyser.</span>""<ul><li><span style=""color: rgb(63, 63, 63); background-color: rgb(255, 255, 255);"">oxidizing agent/«acidified» potassium dichromate(VI) converts ethanol to ethanoic acid&nbsp;</span></li><li><span style=""color: rgb(63, 63, 63); background-color: rgb(255, 255, 255);"">colour change «from orange to green» is measured/analysed «using photocell»&nbsp;</span></li></ul>"
"<span style=""color: rgb(63, 63, 63); background-color: rgb(247, 247, 247);"">State an analytical technique used to separate anabolic steroids from other compounds in an athlete’s urine or blood.</span>"<ul><li>gas chromatography</li><li>high performance liquid chromatography</li></ul>