Poland Liceum ogólnokształcące, klasa IV Chemistry (extended level)
Chapters: 6
1. Esters and fats
Esters and fats
- Esters: Sweet-Smelling Compounds From Acids and Alcohols – An ester forms when a carboxylic acid reacts with an alcohol: acid + alcohol ⇌ ester + water. The acid loses –OH, the alcohol loses H, and the ester bond –COO– joins the two parts. Concentrated sulfuric acid is the catalyst and also removes water, so more ester forms. Esters smell fruity and are used in flavours, perfumes and solvents. Water splits esters back (hydrolysis); with an alkali this is saponification. Fats and oils are esters of glycerol with three fatty acids; boiling them with NaOH gives soap and glycerol.
2. Nitrogen-containing organic compounds
Amines · Amino acids and peptides
- Amines: Structure, Naming, Preparation, Basicity and Reactions – An amine is ammonia with one, two or three H atoms swapped for carbon groups. The N keeps a lone pair, so amines are bases and nucleophiles. Count the C atoms on N to get 1°, 2° or 3°. Make them by reducing nitro compounds, nitriles or amides, from alkyl halides + NH₃, by Gabriel (1° only) or Hofmann bromamide (one C fewer). Alkyl groups push electrons and raise basicity; the ring in aniline pulls the pair away and lowers it. Key reactions: salts with acids, acylation, carbylamine test (1°), Hinsberg test (1°/2°/3°), nitrous acid and ring substitution in aniline.
- Proteins and Enzymes: Amino Acids, Peptide Bond, Structure and Denaturation – Proteins are long chains of amino acids. Each amino acid has an amino group (–NH₂), an acid group (–COOH), a hydrogen and a side group R on one carbon. The –COOH of one amino acid joins the –NH₂ of the next, losing water, to make a peptide bond (–CO–NH–). The order of amino acids is the primary structure; coils and sheets are the secondary structure; the full 3D fold is the tertiary structure; several chains together make the quaternary structure. Heat, acid or alcohol can undo the folds (denaturation). Enzymes are mostly proteins that speed up reactions in the body.
3. Proteins
Proteins
- Proteins and Enzymes: Amino Acids, Peptide Bond, Structure and Denaturation – Proteins are long chains of amino acids. Each amino acid has an amino group (–NH₂), an acid group (–COOH), a hydrogen and a side group R on one carbon. The –COOH of one amino acid joins the –NH₂ of the next, losing water, to make a peptide bond (–CO–NH–). The order of amino acids is the primary structure; coils and sheets are the secondary structure; the full 3D fold is the tertiary structure; several chains together make the quaternary structure. Heat, acid or alcohol can undo the folds (denaturation). Enzymes are mostly proteins that speed up reactions in the body.
4. Sugars
Carbohydrates
- Carbohydrates: Classification, Glucose, Disaccharides and Polysaccharides – Carbohydrates are sugars and the big molecules made from sugars. Chemically they are polyhydroxy aldehydes or ketones (many –OH groups plus one C=O), or things that give these on hydrolysis. We sort them by how many sugar units they have: one (monosaccharide), two to ten (oligosaccharide) or many (polysaccharide). Glucose is an aldose with six carbons; fructose is a ketose. Two units join by a glycosidic (–O–) bond to give disaccharides like sucrose, maltose and lactose. Hundreds join to give starch, cellulose and glycogen.
5. Chemistry around us
Chemistry in daily life
- Science in Daily Life – Science is not only in labs. Cooking uses chemical changes. Soap cleans because one end of its particle likes water and the other likes oil. Acids and bases react, for example vinegar and baking soda give carbon dioxide. Sport is full of forces and motion. Films, adverts and social media use science too, so we must check claims for evidence.
6. Environmental protection
Environmental chemistry
- Pollution: Air, Water, Land and Noise – Pollution is the release of harmful substances or energy into air, water or land faster than nature can remove them. Main air pollutants are particulates, carbon monoxide, sulfur dioxide, nitrogen oxides and ozone; they cause acid rain and smog. Water pollution by nutrients, sewage and toxins causes eutrophication and biomagnification. We reduce pollution by cutting emissions at the source, cleaning waste before release, and the 3Rs.