Flashcards
Topic 4.2 Solutions of Ionic Compounds
Cards in this deck (14)
- 1Are ionic substances soluble in water?- Many ionic substances are soluble in water.
- Being an ionic substance, the ions separate and interact. - 2What happens to ionic substances if they're not very soluble in water?When ionic substances are not very soluble in water they form precipitates when solutions containing the relevant ions are mixed.
- 3What is an ion-dipole interaction?An ion has a full positive or negative charge (rather than the partial delta charge of a dipole) and so can interact with the dipoles of water.
- 4What is the solubility of ionic compounds determined by?Solubility of ionic compounds is determined by the strength of the ionic bond – the stronger the ionic bond, the more force holding the ions together, the more difficult to break and the less soluble the compound will be.
- 5Example of solubility of ionic compounds being determined by the strength of the ionic bondFor example, sodium chloride (NaCl) is water soluble, while aluminium chloride (AlCl3) is not water soluble.
All group 1 metal salts are soluble (they have a 1+ charge). All nitrates are soluble. - 6What nitrates NO3- compounds are soluble?All nitrates
- 7What Chloride Cl-, Bromide Br-, and Iodides I- compounds soluble?Soluble = Most halides
Insoluble = Silver, Lead, and Mercury halides - 8What is a dissociation reaction and what does this entail?When an ionic compound dissolves in water, the compound splits into its component ions. This is called dissociation.
- 9Give an example of a dissociation reactionNaCl(s) --> Na+(aq) + Cl-(aq)
- 10What is a hydration reaction? Give an exampleAn anhydrate is the substance that remains after the water is removed from a hydrate. When a hydrate is heated the water molecules are driven off as steam, leaving behind the water-free anhydrate.
- 11What is a precipitation reaction?- A precipitation reaction refers to the formation of an insoluble salt when two solutions containing soluble salts are combined. The insoluble salt that falls out of solution is known as the precipitate, hence the reaction's name.
- Precipitation reactions can help determine the presence of various ions in solution. - 12Give an example of a precipitation reactionSilver nitrate + sodium chloride --> silver chloride + sodium nitrate
AgNO3(aq) + NaCl(aq) --> AgCl(s) + NaNO3(aq) - 13What can the solubility table be used to identify in a precipitation reaction?The precipitate
- 14Why does soap form scum in water containing calcium ions?- In hard water, the presence of Ca2+ and Mg2+ ions react with the soap to form a precipitate
- The precipitate is known as soap scum
Calcium and Magnesium form a strong ionic bond with the carboxylate anion
- calcium carboxylate and magnesium carboxylate salts are insoluble
- These carboxylate salts clump together and do not perform the function that the ionic head in soap is required to perform to cut away dirt and grease.
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- Chemistry Stage 1 Flashcards on Topic 4.2 Solutions of Ionic Compounds , created by Mabel G on 16/08/2018.
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