7.1 - Acids and Bases Flashcards
What are acids? [2]
- substances that release hydrogen ions when dissolved in water
- resulting in a pH less than 7
What is pH? [2]
- a number
- shows how acidic or basic a solution is
What are bases? [2]
- substances that release hydroxide ions when dissolved in water
- resulting in a pH greater than 7
What is the reaction between acid + metal? [2]
acid + metal –> salt + hydrogen gas
What is the reaction between acid + base? [2]
acid + base –> salt + water
What is the reaction between an acid + base called and what is it? [2]
- neutralisation
- chemical reaction
What is the reaction between acid + carbonate? [2]
acid + carbonate –> salt + water + carbon dioxide
What is a Base? [2]
- usually oxides or hydroxides of metals
What are alkalis? [1]
- bases that are soluble in water
What is the reaction between base + acid? [2]
base + acid –> salt + water
What is the reaction between base + ammonium salts? [2]
base + ammonium salt –> salt + water + ammonia gas
What are acids defined as? [1]
proton donors
What are alkalis defined as? [1]
proton acceptors
What type of bonding is expected in acids? [1]
covalent bonds
What type of bonding is expected in alkalines? [1]
ionic bonds
What is an ionic bond? [2]
the electrostatic force of attraction between oppositely charged ions
What is a covalent bond? [2]
shared pair of electrons between two atoms
All ___ are ___ but not all ___ are ___. [4]
- alkalis
- bases
- bases
- alkalis
What is the pH for acids? [1]
<7
What is the pH for alkalines? [1]
> 7
Why is a H+ ion a proton? [2]
- hydrogen atom has one proton and one electron
- when it loses the electron only the proton is left
What is a strong acid? [2]
- an acid that completely dissociates in an aqueous solution
- all of its molecules break apart into ions
What is a weak acid? [2]
- an acid that only partially dissociates in an aqueous solution
- only some of its molecules break apart into ions
What is an example of a strong and weak acid? [2]
- strong: HCl
- weak: ethanoic acid
What is universal indicator? [2]
- a substance that changes colour
- shows how acidic or alkaline a solution is
How are the H+ concentration related to the acid strength and the pH? [3]
- the higher the hydrogen ion concentration
- the stronger the acid
- the lower the pH
How are the OH- concentration related to the alkali strength and the pH? [3]
- the higher the hydroxide ion concentration
- the stronger the alkali
- the higher the pH
How do we compare the neutrality, relative acidity and relative alkalinity using universal indicator? [2]
- add a drop of universal indicator into the substance to be tested
- compare its colour change to the pH colour chart
What does it mean if a substance is neutral? [3]
- turns green
- equal concentrations of H+ ions and OH- ions
- pH 7
What is the equation for neutralisation? [1]
H⁺ + OH⁻ –> H₂O
