Soluble Salts Flashcards

All 6 cards in this deck

Which types of insoluble solid can be added to a dilute acid to make a soluble salt?

Metals, metal oxides, metal hydroxides and metal carbonates.

Why is the insoluble solid added to the acid in excess when preparing a soluble salt?

So that all the acid reacts, and the excess solid can then be filtered off.

Give one observation showing that the insoluble solid added to an acid is in excess.

Solid remains in the mixture (it no longer disappears), or effervescence stops with a carbonate.

Why is the reaction mixture filtered when preparing a soluble salt?

To remove the excess insoluble solid, leaving a solution of the salt.

What are the steps to obtain solid crystals from a salt solution?

e.g. from zinc chloride solution

1. Heat the solution gently to evaporate some water, until crystallisation point (crystals start to form).
2. Leave the solution to cool and crystallise.
3. Pat the zinc chloride crystals dry with filter paper.

True or false? Any metal can be added to a dilute acid to make a soluble salt.

False. Unreactive metals such as copper do not react with dilute acids, so a copper oxide or copper carbonate must be used instead.