U4 Organic materials, structure & properties Flashcards
B.p M.p trends with number of carbon atoms in Alkanes&Alkenes
More carbon atoms, larger size of moelcule, stronger IMF bonds, higher temp needed to overcome bonds.
Straight chain higher b.p than branched.
What is volatility? Discuss volatility in terms of the functional groups
Volatility refers to the ease of a substance becoming a gas. Low volatility = High energy needed to become gas. Breaking of Intermolecular forces of the molecules results in gaseous form. Stronger IMF, More energy needed to break, lower the volatility.
Solubility trends of organic in water.
More carbons, the more hydrophobic non-polar parts, the more insoluble it becomes. Alcohol/Carboxylic etc have polar bonds, so more easily soluble.
What is a polymer?
Many monomers bonded together through polymerisation. -> Condensation / Addition
Brief describe Primary vs Secondary vs Tertiary vs Quarternary
Primary: Different order sequence of monomers. e.g ABUHD vs ODJBL
Secondary: The shape of these polymer. a-helix / b-pleated sheets. Due to IMF interactions.
Tertiary: Refers to the overall 3-D shape of polymer. Depends on types of bonding etc
Quarternary: Shape of two ore more polymers bonded together.
Biodegradability in polymers
The breakdown of organic matter. Natural polymers easier to degrade. Enzymes break down substances like protein etc.
Density in polymers
The mass per unit of volume. Increase in branching / side chain = Decrease in ability to compact = Decrease in density
What are enzymes, and describe the characteristics of biological catalysts.
Enzymes are biological catalysts, usually large proteins, used to increase reaction rates. They have high catalytic power and display high specificity for the substrates (don’t interact with other substances)
Usually end with -ase
What are amino acids
Organic substances that contain both an amine and carboxylic acid function groups.
What are proteins? Explain polypeptides and peptides.
Proteins are one or more polypeptides. Polypeptides are a specific type of polyamide where there is chain of many bonded peptides. Peptides are polymers of amino acid monomers bonded together through condensation polymerisation.
What are the amide bonds (peptide bonds) in a polypeptide.
The bond between the carbon of the carboxylic tail of one peptide to the nitrogen amine tail of another peptide.
Explain the secondary structure of proteins. (a-helix b-sheets)
A-helix, forms a spiral like structure due to the hydrogen bonding between the oxygen in the carbonyl group (C=O) to the hydrogen (H-N) in the amine group of another peptide.
B-sheets forms folded paper like structure also due to the hydrogen bonding.
What are carbohydrates?
Natural polymers that are made of mono/di/polysaccharides.
What are monosaccharides?
Sugars that cannot be further decomposed. Have the empirical formula CH2O. Contain either aldose (aldehyde group) or ketose (ketone group) and several -OH.
What are the differences between a-glucose and b-glucose?
In a-glucose, the right-most OH group facing down. (In data booklet) In b-glucose this OH group facing up.
Explain the structural properties of starch.
Made of amylose and amylopectin, which are both entirely made of a-glucose monomers. Amylose is straight chain 1-4 glycosidic linkage, whereas amylopectin is branched 1-4/1-6.
Explain structural properties of cellulose.
Polymer of b-glucose. Forms a strong crystalline cross-linked structure.
What are lipids and their types.
Lipids are polymers and large ester molecules like triglycerides. If liquid at room temp, then it is an oil. If solid at room temp, then it is a fat.
What is glycerol?
Propan-1,2,3-triol. 3 Carbons, 3 -OH ends.
What is a fatty acid? Distinguish between poly/mono/un/saturated.
A very long carbon chain with a carboxylic end. Can have 1 C=C double bond (monounsaturated), many double bonds (polyunsaturated) or no double (saturated).
How are triglycerides formed? Include reversal reaction
Glycerol + 3 fatty acids -> triglyceride + h2o.
In condensation reaction.
Hydrolysis reaction can be used to split.
How are soaps produced? Explain their structure + why they are useful
Triglceride reacts with NaOH/KOH -> Glycerol + Sodium salts of fatty acids.
Has a carboxylate ion head O- Na+, which is polar and bonds with the polar water, whereas the long carbon chain is hydrophobic but bonds with the dirt and grease.
Can soaps be used in hard water?
Hard water is water with calcium or magnesium ions however the carboxylic tail of the soap molecules forms an insoluble precipitate when reacting with the ions. Detergents do not contain a carboxylate tail but does have a hydrophilic tail.
What is polyethene and how is it created?
Polyethene is when multiple ethene molecules link together through addition polymerisation to form long chains. They can either be LDPE or HDPE.
