Salts from metals Flashcards
(11 cards)
Define salt.
A salt is a chemical compound formed when the hydrogen ions (H⁺) in an acid are partially or completely replaced by metal ions or ammonium ions (NH₄⁺).
Name a salt formed between a metal and sulfuric acid or hydrochloric acid.
Zinc + sulfuric acid → zinc sulfate + hydrogen
Salt formed: ✅ Zinc sulfate (ZnSO₄)
Magnesium + hydrochloric acid → magnesium chloride + hydrogen
Salt formed: ✅ Magnesium chloride (MgCl₂)
What is the general word equation for making a salt from a metal and an acid?
Metal + Acid → Salt + Hydrogen gas
Which types of metals are suitable for reacting with acids to make salts?
Metals above hydrogen in the reactivity series
Must not be too reactive (e.g. avoid potassium, sodium)
Examples: Magnesium, Zinc, Iron
What acids are commonly used to make salts? What salts do they form?
Hydrochloric acid → chlorides
Sulfuric acid → sulfates
Nitric acid → nitrates
Describe the method for making a salt by reacting a metal with an acid.
1.Add excess metal to dilute acid
2.Reaction produces salt + hydrogen gas (fizzing)
3.Wait until fizzing stops (acid used up)
4.Filter to remove unreacted metal
5.Evaporate solution gently
6.Allow crystals to form and dry
Why is excess metal used in the reaction?
To ensure all the acid reacts
Prevents leftover acid in final salt solution
📝 1. Describe how you would make pure, dry crystals of copper sulfate in the lab.
Pour about 50 cm³ of dilute sulfuric acid into a beaker and gently heat it using a Bunsen burner.
Add small amounts of copper(II) oxide to the warm acid and stir with a glass rod.
Continue adding the copper(II) oxide until no more dissolves (the excess is visible).
Filter the mixture using filter paper and a funnel to remove the unreacted copper oxide.
Pour the filtrate (blue solution) into an evaporating basin and gently heat until some water has evaporated.
Leave the solution to cool, and blue copper sulfate crystals will form. Remove and dry them with filter paper.
📝 2. Why is it important to add excess copper oxide when reacting it with sulfuric acid?
To ensure all the sulfuric acid has reacted, so the reaction goes to completion.
This prevents any acid from remaining in the final solution, giving a pure salt.
📝 3. What would you observe when copper(II) oxide is added to sulfuric acid?
The solution gradually turns a clear blue as copper sulfate forms.
The black solid copper oxide disappears until excess is added, which remains unreacted.
📝 4. Write the word and balanced symbol equation for the reaction.
Word Equation:
Sulfuric acid + Copper(II) oxide → Copper sulfate + Water
H2SO4+CuO→CuSO 4+H2O
