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15 Cards in this Set
- Front
- Back
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Explain why the second ionisation enthalpy of calcium is smaller than the third ionisation enthalpy of calcium |
-(2nd IE) - removing electron from shell further nucleus or (3rd IE) removing electron from shell closer or nucleus - (2nd IE) electron experiences less attraction or (3rd IE) (electron experiences) more attraction from nucleus |
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Define the term electronegativity |
- The ability of an atom to attract electrons in a (covalent ) bond |
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What is the name given to the group -SO3H and -SO3- ? |
- Sulfonic acid - sulfonate |
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What is mean by unsaturation in fatty acids? |
- The presence of C=C/alkene groups |
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What is E/Z (CIZ/Trans) isomerism? |
- the C=C double bond prevents rotation - there must be two different groups on each carbon of the carbon-carbon double bond |
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Explain the E(trans) form of an unsaturated fatty acid has a higher melting point than the Z(cis) version? |
- molecules / chains can pack/ line up together more closely - Intermolecular bonds are stronger - more energy required to melt/break i.m.b's |
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What is an enantiomer? |
a non-sumperimposable mirror image |
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Explain the meaning of the term 'pharmacophore' |
-part/area or region of the molecule/structure that either binds to a receptor /enzyme or is responsible for the medicinal action of the drug |
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Explain how inhibition slow down the rate of enzyme-catalysed reaction |
-Inhibitor binds with/ forms bonds into the active site of the enzyme |
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A substance used as an antidote for arsenic poisoning is itself toxic. Suggest a test chemists would do before this drug is a allowed to be used |
- determining a safe does of the chemical - determining how toxic it is compared to arsenic |
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An insecticide is toxic to people and animals. Suggest 2 arguments that farmers may give to able to continue using this product |
- no effective alternatives available -it can be used with suitable care in low concentrations - it is needed to produce a better yield of food or to boost crop profit/keep food price cheap |
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identify some of the steps involved in going from discovering a substance discovered in fungi to a synthetic statin fro medical use |
- show that a compound has medicinal properties - analyse /work out the pharmacophore - synthesise (similar molecules ) - clinical trials |
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What is an electrophile? |
- molecule /ion with partial positive / positive charge - attracted to regions of high electron density/negative charge - accepts a pair of electron to form a covalent bond |
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Give the conditions needed for the coupling reaction between a diazonium salt and an aromatic amine or phenol to make an azo dye |
- alkaline conditions / NaOH - low temperature / below 10*C |
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Why is an ionic substance soluble in water? |
- Ionic bonds in the lattice have to be broken and hydrogen bonds between water molecules have to be broken - require energy ( endothermic ) - ion-dipole bonds formed between water molecules and ions - forming ion-dipole bonds releases energy (exothermic ) - if more energy released than put in the substance is likely to be soluble |
