Year 11 Double Chemistry - Key Concepts

These flashcards cover key terms and concepts related to chemistry, including bonding types, the properties of materials, reactions, and environmental implications.

Ionic Bonding

Occurs between metals and non-metals where electrons are transferred, resulting in electrostatic attraction between oppositely charged ions.

Covalent Bonding

Occurs between non-metals where electrons are shared in pairs.

Metallic Bonding

Occurs between metals with a regular arrangement of positive ions surrounded by a 'sea' of delocalised electrons.

High Melting and Boiling Points of Ionic Compounds

Due to strong forces between ions that require a lot of energy to break.

Giant Covalent Compounds

Have high melting and boiling points due to strong bonds between atoms that need a lot of energy to break.

Simple Covalent Molecules

Have low melting and boiling points due to weak forces between molecules that do not require much energy to break.

Conductivity of Ionic Compounds

Ionic compounds conduct electricity only when molten or in solution because the ions are free to move.

Conductivity of Metallic Substances

Metallic substances conduct electricity due to free electrons that can move throughout the structure.

Covalent Compounds and Electricity

Covalent compounds do not conduct electricity because there are no free electrons.

Melting Point of MgO vs. NaCl

MgO has a higher melting point than NaCl due to greater charges on magnesium and oxide ions resulting in stronger attraction.

Hardness of Diamond

Diamond is hard because each carbon atom is strongly bonded to four others via covalent bonds.

Softness of Graphite

Graphite is soft because each carbon is bonded to three others in layers, with weak forces between the layers allowing them to slide over one another.

Graphite and Electrical Conductivity

Graphite conducts electricity because each carbon atom is bonded to three others, leaving one free electron to move throughout the structure.

Fullerenes

Used for applications such as drug delivery, lubricants, and catalysts.

Nanometre and Nanoparticle Size

A nanometre (nm) is 1 billionth of a metre; a nanoparticle contains 1-100 atoms.

Properties and Uses of Silver Nanoparticles

Properties: antibacterial, antiviral, antifungal. Uses: plasters, antiseptic sprays, socks, deodorant sprays.

Properties and Uses of Titanium Dioxide Nanoparticles

Properties: absorb and reflect UV light, transparent. Uses: sunscreen, self-cleaning windows.

Risks of Nanoscience

Long-term effects are unknown and nanoparticles could easily be absorbed into the body or environment.

Smart Material

Materials that have properties that change reversibly when a change occurs in their environment.

Thermochromic Pigments

Change colour with temperature.

Photochromic Pigments

Change colour with changing light intensity.

Polymer Gels

Absorb water and swell or release water and shrink due to changes in pH or temperature.

Shape Memory Alloys and Polymers

Regain original shape when heated.

Universal Indicator - Strong Acid

Appears red with a pH of 1-2.

Universal Indicator - Strong Alkali

Appears purple with a pH of 13-14.

Universal Indicator - Neutral Substance

Appears green with a pH of 7.

Ionic Composition of Acids and Alkalis

Acids contain H+ (Hydrogen ions), alkalis contain OH- (Hydroxide ions).

Reaction of Acid with Metal

Produces a salt and hydrogen.

Reaction of Acid with Carbonate

Produces fizzing due to the formation of carbon dioxide.

Neutralisation Reaction Products

When an acid reacts with a base, it produces a salt and water.

Ionic Equation for Neutralisation

The equation represents the cancellation of ions to show H+ + OH- → H2O.

Ore Definition

A mineral found in the Earth's crust that contains enough metal to make it worthwhile extracting.

Native State Metals

Gold and silver are metals found in the ground in their native state.

Oxidation and Reduction (Oxygen Terms)

Oxidation is gaining oxygen; reduction is losing oxygen.

Displacement Reaction Definition

A chemical reaction in which a more reactive element displaces a less reactive element from its compound.

Blast Furnace Raw Materials

Iron ore, coke, limestone, hot air.

Coke in Blast Furnace

Used as fuel and produces carbon monoxide for reduction.

Limestone in Blast Furnace

Added to remove impurities as slag.

Hot Air in Blast Furnace

Provides oxygen so that the coke can burn.

Electrolysis

The process of splitting up a compound using electricity.

Oxidation and Reduction (Electron Terms)

Oxidation involves the loss of electrons; reduction involves the gain of electrons.

Positive Ions Movement

When positive ions move to the negative electrode, they gain electrons (are reduced).

Negative Ions Movement

When negative ions move to the positive electrode, they lose electrons (are oxidised).

Aluminium Ore Cryolite Use

Aluminium ore is dissolved in molten cryolite to save energy due to a lower melting point.

Oxygen Production During Electrolysis

Oxygen reacts with carbon electrodes during the electrolysis of aluminium oxide, producing carbon dioxide.

Properties of Metals

High melting points, malleable, ductile, good conductors of heat and electricity.

Transition Metals Location

Found between groups 2 and 3 on the periodic table.

Transition Metals vs. Normal Metals

Transition metals can form more than one type of ion and form coloured compounds.

Solution Colors of Ions

Fe2+ is pale green, Fe3+ is brown, and Cu2+ is blue.

Alloy Definition

A mixture made by mixing molten metals.

Factors Influencing Metal Extraction Plant Location

Transport links, electricity supply, distance from urban areas.

Activation Energy Definition

The minimum amount of energy needed to start a reaction.

Exothermic Reaction Description

Exothermic reactions release energy to the surroundings, increasing temperature.

Endothermic Reaction Description

Endothermic reactions absorb energy from the surroundings, decreasing temperature.

Crude Oil Definition

A mixture of hydrocarbons.

Hydrocarbon Definition

A compound made of hydrogen and carbon only.

Crude Oil Separation Method

Separated by fractional distillation, vaporised and condensed at different points in the column.

Carbon Chain Length Effects on Viscosity and Colour

Longer chains increase viscosity and darken color.

Carbon Chain Length Effects on Boiling Point

Longer chains result in higher boiling points due to stronger molecular forces.

Carbon Chain Length Effects on Ignition

Shorter chains ignite more easily.

Combustion of Fuels Description

The burning of fuels in oxygen to produce carbon dioxide and water.

Hydrogen Fuel Advantages

Water as the only combustion product (non-polluting) and renewable (derived from water).

Hydrogen Fuel Disadvantages

High energy requirement for production and bulky storage solutions.

Fire Triangle Components

Fuel, oxygen, heat.

Cracking Definition

Heating hydrocarbons at high temperatures with a catalyst to produce smaller molecules.

Alkene General Formula

CnH2n where n is the number of carbon atoms.

Preparing Salt Crystals Method

Add excess base to neutralise acid, filter to remove unreacted base, and evaporate water to form crystals.

First Five Alkanes

Methane, ethane, propane, butane, pentane.

Testing for Alkenes Method

Add bromine water, which will change from orange-brown to colorless.

Monomer Definition

A small reactive molecule that can be joined to make a polymer.

Polythene Uses

Used for bags and plastic bottles.

Poly(propene) Uses

Used for ropes and crates.

PVC and PTFE Uses

PVC is used for drain pipes and window frames; PTFE is used for non-stick pans.

Environmental Issues with Plastics

Plastic waste occupies landfill space, does not biodegrade, and is derived from non-renewable crude oil.