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ScotlandChemistry

Area 2: Nature's Chemistry

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What chemistry gives food its flavour and aroma?

Flavour molecules, the effect of cooking on flavour, the difference between aldehydes and ketones, oxidation of aldehydes, and the volatility and solubility of flavour and aroma compounds.
An SQA Higher Chemistry answer on the chemistry of cooking, covering flavour molecules, how cooking changes flavour, the difference between aldehydes and ketones and their carbonyl group, the oxidation of aldehydes to carboxylic acids, and the volatility and solubility of aroma compounds.
10 min answer →

How are esters, fats and oils made and broken down?

The formation of esters by condensation of an alcohol and a carboxylic acid, the ester link, hydrolysis of esters, and the structure of fats and oils as esters of glycerol and fatty acids, including saturated and unsaturated chains.
An SQA Higher Chemistry answer on esters, fats and oils, covering the condensation reaction that forms an ester from an alcohol and carboxylic acid, the ester link, hydrolysis, and the structure of fats and oils as glycerol esters of saturated and unsaturated fatty acids.
11 min answer →

What chemistry lies behind fragrances and protecting skin from the Sun?

Essential oils and terpenes as components of fragrances, the structure of terpenes built from isoprene units, the oxidation of terpenes, and how UV light damages skin and how sunblocks and free-radical scavengers protect it.
An SQA Higher Chemistry answer on fragrances and skincare, covering essential oils and terpenes built from isoprene units, the oxidation of terpenes to flavour and aroma compounds, how ultraviolet light damages skin, and how sunblocks and free-radical scavengers provide protection.
10 min answer →

Why does food go off, and how do antioxidants protect it?

Oxidation as the loss of electrons, the oxidation of alcohols and aldehydes, the rancidity of edible oils caused by the oxidation of carbon-to-carbon double bonds, and the action of antioxidants in preventing oxidation.
An SQA Higher Chemistry answer on the oxidation of food, covering oxidation as electron loss, the oxidation of alcohols to aldehydes and carboxylic acids, the rancidity caused by oxidation of double bonds in edible oils, and how antioxidants protect food by being oxidised themselves.
10 min answer →

How are proteins built from amino acids and how do enzymes work?

Amino acids as the building blocks of proteins, the formation of the peptide (amide) link by condensation, the hydrolysis of proteins to amino acids, essential amino acids, and how heat denatures the structure of enzymes.
An SQA Higher Chemistry answer on proteins, covering amino acids as building blocks, the formation of the peptide link by condensation, hydrolysis back to amino acids, essential amino acids, and how heating denatures enzymes by changing their three-dimensional shape.
10 min answer →

How do soaps and detergents clean, and how do emulsifiers keep mixtures stable?

The production of soap by alkaline hydrolysis of fats and oils, the structure of soap with hydrophilic and hydrophobic ends, how soap removes oily dirt, hard water, detergents, and the action of emulsifiers in emulsions.
An SQA Higher Chemistry answer on soaps, detergents and emulsions, covering how soap is made by alkaline hydrolysis of fats and oils, the hydrophilic and hydrophobic ends of a soap ion, how oily dirt is removed, the advantage of detergents in hard water, and how emulsifiers stabilise emulsions.
10 min answer →