Acids, Bases & Salts, Identification of Ions & Gases, Preparation of Salts, Experimental Techniques

Flashcards covering vocabulary related to acids, bases, salts, identification of ions and gases, preparation of salts and experimental techniques.

Acid

A substance with a pH below 7 that can neutralise a base, forming a salt and water. When added to water, they form positively charged hydrogen ions (H+).

Base

A substance with a pH above 7 that can neutralise an acid, forming a salt and water. Bases are usually oxides or hydroxides of metals and form negative hydroxide ions (OH-) when added to water.

Alkali

A base that is water-soluble.

Neutralisation Reaction

The reaction between an acid and a base, which produces a salt and water.

Salt

A compound formed when the hydrogen atom in an acid is replaced by a metal.

Indicator

A substance that changes color depending on whether it is in an acidic or alkaline solution.

Litmus

A two-color indicator that is red in acid and blue in alkali. It is extracted from lichens. Not suitable for titration

Methyl Orange

A two-color indicator that is red in acid and yellow in alkali. It can be used in titration, as it has a very sharp change of colour.

Thymolphthalein

A two-color indicator that is colourless in acid and blue in alkali. It can be used in titration, as it has a very sharp change of colour.

pH Scale

A scale from 1 to 14 used to measure the acidity or alkalinity of a solution. Acids have a pH below 7, alkalis have a pH above 7, and a neutral solution has a pH of 7.

Universal Indicator

A mixture of different indicators used to measure pH, which is matched against a colour chart.

Strong Acid

An acid that completely dissociates (or ionises) in water, producing a high concentration of H+ ions and a very low pH.

Weak Acid

An acid that partially dissociates (or ionises) in water, producing a lower concentration of H+ ions and a pH closer to the middle of the pH scale.

Acidic Oxide

An oxide formed when a non-metal element combines with oxygen. It reacts with bases to form a salt and water, and produces an acidic solution when dissolved in water.

Basic Oxide

An oxide formed when a metal element combines with oxygen. It reacts with acids to form a salt and water, and produces a basic solution when dissolved in water.

Amphoteric Oxide

An oxide that can behave as both acidic and basic, depending on whether the other reactant is an acid or a base. In both cases, salt and water are formed.

Neutral Oxide

An oxide that does not react with either acids or bases.

Carbonate Ion (CO3 2-)

An anion that when tested with dilute acid, releases CO2 gas which turns limewater cloudy.

Halide Ions (Cl-, Br-, I-)

An anion that, when tested with acidified silver nitrate, forms precipitates that can be white (AgCl), cream (AgBr) or yellow (AgI).

Nitrate Ion (NO3-)

An anion that, when tested with aqueous NaOH and aluminium foil warmed gently, releases ammonia gas.

Sulfate Ion (SO4 2-)

An anion that, when tested with acidified barium nitrate solution, forms a white precipitate of barium sulfate.

Sulfite Ion (SO3 2-)

An anion that, when tested with dilute acid, produces a gas that turns potassium manganate(VII) solution from purple to colourless.

Ammonium Ion (NH4+)

A cation that, when warmed with sodium hydroxide solution, releases ammonia gas, which turns damp red litmus paper blue.

Flame Test

A test used to identify metal cations by the color of the flame they produce when a compound is heated in a Bunsen burner flame.

Ammonia Gas (NH3)

A gas with a characteristic sharp choking smell that turns damp red litmus paper blue.

Carbon Dioxide Gas (CO2)

A gas that, when bubbled through limewater (calcium hydroxide solution), turns the limewater cloudy white.

Chlorine Gas (Cl2)

A gas that turns damp blue litmus paper red and then bleaches it white.

Hydrogen Gas (H2)

A gas that burns with a loud 'squeaky pop' when a burning splint is held at the open end of a test tube of the gas.

Oxygen Gas (O2)

A gas that relights a glowing splint.

Sulfur Dioxide Gas (SO2)

A gas that, when bubbled through an acidified solution of potassium manganate(VII), changes the solution from purple to colourless.

Soluble Salt

A salt that dissolves in water.

Insoluble Salt

A salt that does not dissolve in water. These can be prepared via precipitation reactions.

Hydrated Salt

A salt that contains water molecules within its crystal structure.

Anhydrous Salt

A salt that does not contain water molecules in its structure.

Volumetric Pipette

The most accurate way of measuring a fixed volume of liquid

Burettes

The most accurate way of measuring a variable volume ofliquid between 0 cm3 and 50 cm3.

Downard displacement of water

Method to measure volume of gas - where you collect the gas in a measuring cylinder that is inverted in water

Saturated Solution

A Solution with the maximum concentration of solute dissolved in the solvent

Solution

The mixture formed when a solute is dissolved in a solvent