Acids, Bases, and Salts Practice Flashcards

Flashcards covering the definitions, properties, reactions, and classifications of acids, bases, and salts, including indicators and neutralisation techniques.

What is always formed when an acid reacts with a base?

A salt.

What are acid molecules composed of when they are not dissolved in water?

Covalent molecules which can be solid, liquid, or gas at room temperature.

What do all acid molecules contain?

Hydrogen, such as hydrochloric acid ($HCl$), nitric acid ($HNO_3$), and sulfuric acid ($H_2SO_4$).

What are the two ways an acid may be defined?

1. A substance containing hydrogen which can be replaced directly or indirectly by a metal to form a salt. 2. A proton donor.

Why are $H^+$ ions in aqueous acids referred to as single protons?

Each $H^+$ ion is a hydrogen nucleus containing a single proton, formed when a hydrogen atom ($H$) loses its valence electron.

What does an acid donate when reacting with another reactant?

Its $H^+$ ions or protons.

List five general properties of acids in aqueous solution.

1. Sour taste. 2. Corrosive. 3. Change blue litmus to red. 4. pH value less than 7. 5. Conduct an electric current (electrolytes).

What are the products of a reaction between an acid and a reactive metal (except nitric acid)?

A salt and hydrogen ($H_2$).

Why does nitric acid release nitrogen dioxide ($NO_2$) instead of hydrogen when reacting with metals?

Nitric acid is an oxidising agent.

What are the products of a reaction between an acid and a metal carbonate or metal hydrogencarbonate?

A salt, carbon dioxide ($CO_2$), and water ($H_2O$).

How is 'basicity' of an acid defined?

The number of $H^+$ ions produced per molecule of acid when the acid dissolves in water.

Match the acid type to the number of $H^+$ ions produced: monobasic, dibasic, and tribasic.

Monobasic produces one $H^+$ ion; dibasic produces two $H^+$ ions; tribasic produces three $H^+$ ions.

What is a base?

Metal oxides (e.g., $CaO$), metal hydroxides (e.g., $Zn(OH)_2$), and ammonia ($NH_3$).

What is an alkali?

A base which dissolves in water to form a solution that contains $OH^-$ ions.

List five general properties of aqueous solutions of alkalis.

1. Bitter taste. 2. Corrosive. 3. Feel soapy. 4. Change red litmus to blue. 5. pH value greater than 7 (electrolytes).

What products are formed when bases are heated with ammonium salts?

A salt, ammonia ($NH_3$), and water ($H_2O$).

What are the colors of screened methyl orange in acidic and alkaline solutions?

Red in acidic solutions and green in alkaline solutions.

What is the difference between a strong acid and a weak acid?

A strong acid is fully ionised in water (high $H^+$ concentration), while a weak acid is only partially ionised (low $H^+$ concentration).

How are normal salts and acid salts distinguished?

Normal salts are formed when all $H^+$ ions in an acid are replaced by metal or ammonium ions. Acid salts are formed when $H^+$ ions are only partially replaced.

What is an acidic oxide?

An oxide of a non-metal that reacts with alkalis to form a salt and water, and usually reacts with water to form an acid (acid anhydride).

Define an amphoteric oxide and provide three common examples.

An oxide of a metal that reacts with both acid and strong alkali to form a salt and water; examples include aluminium oxide ($Al_2O_3$), zinc oxide ($ZnO$), and lead(II) oxide ($PbO$).

What are neutral oxides?

Non-metal oxides that do not react with acids or alkalis, such as carbon monoxide ($CO$), nitrogen monoxide ($NO$), and dinitrogen monoxide ($N_2O$).

What is the ionic equation for a neutralisation reaction between an aqueous alkali and an aqueous acid?

$$OH^-(aq) + H^+(aq) \rightarrow H_2O(l)$$

Why are neutralisation reactions classified as exothermic?

Because they produce heat energy.

How is the neutralisation point determined using temperature change?

A thermometric titration is performed where acid is added to alkali from a burette, and the point of intersection on a temperature-volume graph identifies the neutralisation point.

What is the effect of heat on Vitamin C (ascorbic acid) during cooking?

Heat oxidises Vitamin C, which destroys it.

How does lime juice treat rust stains?

The citric acid in the juice reacts with the iron(III) oxide ($Fe_2O_3$) in rust to form a soluble compound that washes out.

What chemical treatment can be applied to treat ant stings caused by methanoic acid?

A paste of sodium hydrogencarbonate or calamine lotion (containing zinc oxide) to neutralise the acid.