Mixing and dissolving Lesson 6 of the chemistry course of Mova's primary school: 16 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: the lesson at school .
1 Water molecules crowd round each tiny sugar molecule and carry it off into the liquid, so the sugar is still there, only spread out too small to see. 2 The sugar plus the water make a solution; let the water evaporate and the sugar comes back. 3 Not everything dissolves: sand just sinks, and a glass of water can only hold so much salt before the rest settles at the bottom. 4 Heat, stirring and small grains all make dissolving faster, which is why loose sugar vanishes before a sugar cube does. 5 When something dissolves, its particles spread out among the water particles; it is still there and still has its taste. 6 A dissolved solid can be got back by letting the water evaporate. 7 Hot water dissolves sugar faster and can hold more of it than cold water. 8 Water can hold only a certain amount of salt; after that it is saturated and extra salt settles at the bottom. 9 The Dead Sea is so salty that people float on it like corks; salty water holds you up more than fresh water. 10 Sand does not dissolve in water, because its particles are joined too strongly for water to pull them apart; nail varnish does not dissolve in water either, but it does dissolve in nail varnish remover. 11 Small grains dissolve faster than a lump, because they have more surface for the water to touch; stirring helps too. 12 Squash is a solution: more water makes it more dilute, and a sieve or filter cannot take the cordial back out. 13 Gases dissolve in water too; fish breathe oxygen dissolved in the water, taking it in through their gills, and warm water holds less of it. 14 A bath bomb holds a dry acid and baking soda that react only when water lets them meet, making carbon dioxide bubbles. 15 Instant coffee is coffee liquid that was dried; ground coffee does not fully dissolve, so it needs a filter. 16 As sugar dissolves you can see wavy streams, because the sugary water bends light differently from plain water. ← previous Melting, freezing, boiling and condensingnext → Oil and water, and things that won't mix↑ back to Chemistry This page in Markdown → https://md.mova.elamur.ai/free/en/corpora/school/chemistry/6-mixing-and-dissolving/