What is produced when an acid reacts with a metal?
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What is produced when an acid reacts with a metal?
When an acid reacts with a metal, it produces a salt and hydrogen gas.
What is an alkali?
An alkali is a water-soluble base.
What colour does litmus paper turn in acidic conditions?
In acidic conditions, litmus paper turns red.
True or False?
Thymolphthalein turns blue in alkaline conditions.
True.
Thymolphthalein turns blue in alkaline conditions.
Why is litmus not suitable for titrations?
Litmus is not suitable for titrations because its color change is not sharp and it goes through a purple transition color in neutral solutions.
What is an indicator?
An indicator is a substance that changes colour in acidic or alkaline conditions, used to determine the pH of a solution.
Define the term neutralisation.
A neutralisation reaction is a reaction between an acid and a base to form a salt and water.
True or False?
Effervescence is produced when an acid reacts with a metal oxide or hydroxide.
False.
Effervescence is produced when an acid reacts with a metal carbonate, due to the formation of carbon dioxide gas.
Name the products formed from the reaction between sodium hydroxide and hydrochloric acid.
The products formed from the reaction between sodium hydroxide and hydrochloric acid are sodium chloride and water.
What is the general equation for the reaction of a metal carbonate with an acid?
The general equation for the reaction of a metal carbonate with an acid is:
metal carbonate + acid ⟶ salt + carbon dioxide + water
Write the word equation for the reaction between sodium carbonate and sulfuric acid.
The word equation for the reaction between sodium carbonate and sulfuric acid is:
sodium carbonate + sulfuric acid ⟶ sodium sulfate + water + carbon dioxide
What determines the identity of the salt produced in an acid-base neutralisation reaction?
The identity of the salt produced depends on the acid used and the positive ions in the base.
What substances act as bases in acid-base reactions?
Metal oxides, metal hydroxides and metal carbonates act as bases in acid-base reactions.
Which ions causes a substance to be acidic?
The ion that causes a substance to be acidic is a hydrogen ion / H+.
Which ions causes a substance to be alkaline?
The ion that causes a substance to be alkaline is a hydroxide ion / OH-.
What pH is classed as neutral?
pH 7 is classed as neutral.
What pH range is classed as alkaline?
The pH range for alkaline is 8-14.
What pH range is classed as acidic?
The pH range for an acid is 0-6.
True or False?
The higher the concentration of hydrogen ions in solution, the lower the pH.
True.
The higher the concentration of hydrogen ions, the lower the pH.
True or False?
The higher the concentration of hydroxide ions in solution, the higher the pH.
True.
The higher the concentration of hydroxide ions in solution, the higher the pH.
What is the net ionic equation for neutralisation?
The net ionic equation for neutralisation is:
H+ (aq) + OH– (aq)⟶ H2O (l)
What is the pH of distilled water?
The pH of distilled water is 7.
Describe how to use universal indicator to test the pH of a substance.
To measure the pH of a substance with universal indicator:
Add a few drops of universal indicator solution to the substance.
Check the colour against a colour chart to determine the pH value.
(Universal indicator paper can also be used).
What is a proton donor?
A proton donor is an acid that ionises in solution producing protons (H+ ions).
What is a proton acceptor?
A proton acceptor is a base that accepts protons donated by an acid.
Define strong acid.
A strong acid is an acid that completely dissociates (or ionises) in water, producing solutions of a very low pH.
Define weak acid.
A weak acid is an acid that partially dissociates (or ionises) in water, producing pH values closer to the middle of the pH scale, while still being below 7.
True or False?
HCl is an example of a strong acid.
True.
HCl is an example of a strong acid.
What is the equation for the dissociation of HCl in water?
The equation for the dissociation of HCl in water is:
HCl (aq) → H+ (aq) + Cl- (aq)
True or False?
Weak acids form an equilibrium in water.
True.
Weak acids form an equilibrium in water between molecules and their ions.
What is an example of a weak acid?
An example of a weak acid is propanoic acid (CH3CH2COOH). Carboxylic acids are good examples of weak acids.
Define concentrated solution.
A concentrated solution is a solution that contains a higher number of solute molecules per dm3 of solution.
True or False?
A concentrated acid solution is always stronger than a dilute acid solution.
False.
A concentrated acid solution is not always stronger than a dilute acid solution. It depends on the degree of dissociation.
What is an oxide?
An oxide is a compound made from one or more atoms of oxygen combined with one other element.
What is an acidic oxide?
An acidic oxide is an oxide formed when a non-metal element combines with oxygen, reacting with bases to form a salt and water.
What is a basic oxide?
A basic oxide is an oxide formed when a metal element combines with oxygen, reacting with acids to form a salt and water.
True or False?
CO2 is an example of an acidic oxide.
True.
CO2 is an example of an acidic oxide.
True or False?
CuO is an example of a basic oxide.
True.
CuO is an example of a basic oxide.
What type of solution do acidic oxides produce when dissolved in water?
Acidic oxides produce an acidic solution with a low pH when dissolved in water.
What type of solution do basic oxides produce when dissolved in water?
Basic oxides produce a basic solution with a high pH when dissolved in water.
What is an amphoteric oxide?
An amphoteric oxide is an oxide that can behave as both acidic and basic, depending on whether the other reactant is an acid or a base.
Give two examples of amphoteric oxides.
Two examples of amphoteric oxides are zinc oxide (ZnO) and aluminium oxide (Al2O3).
True or False?
Amphoteric oxides only react with acids.
False.
Amphoteric oxides react with both acids and bases.