C4 - Chemical Changes Flashcards
(21 cards)
Front
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What is the pH scale used for?
To measure how acidic or alkaline a solution is, from 0 (very acidic) to 14 (very alkaline).
What is a neutral pH?
pH 7
What ions do acids produce in aqueous solution?
H⁺ ions
What ions do alkalis produce in aqueous solution?
OH⁻ ions
What is the name of the reaction between an acid and a base?
Neutralisation
What is the word equation for neutralisation?
Acid + Base → Salt + Water
What is a base?
A substance that reacts with an acid to form a salt and water (includes alkalis).
What is an alkali?
A soluble base that produces OH⁻ ions in water.
What is a salt?
A compound formed when the hydrogen in an acid is replaced by a metal or ammonium ion.
Name the salt formed: Hydrochloric acid + sodium hydroxide
Sodium chloride
Name the salt formed: Sulfuric acid + magnesium
Magnesium sulfate
Name the salt formed: Nitric acid + potassium hydroxide
Potassium nitrate
What type of reaction occurs between acids and metals?
Acid + Metal → Salt + Hydrogen
What test confirms the presence of hydrogen gas?
A lit splint makes a squeaky pop.
What is the reactivity series?
A list of metals in order of how easily they lose electrons (how reactive they are).
What is a displacement reaction?
A more reactive metal displaces a less reactive metal from its compound.
What is electrolysis?
The breakdown of an ionic compound using electricity.
Why must the ionic substance be molten or in solution for electrolysis?
So ions are free to move and carry charge.
What type of ions are attracted to the anode during electrolysis?
Negative ions (anions)
What type of ions are attracted to the cathode during electrolysis?
Positive ions (cations)
