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Chemistry S4 keywords and defenitions > Keywords 2 > Flashcards

Flashcards in Keywords 2 Deck (55):

Define double bond

Double bonds are a strong covalent bond made by sharing 2 pairs of electrons.


What does electrolyte mean?

Electrolytes are a liquid containing free- moving ions that is broken down by electricity in the process of electrolysis.


Give me the meaning of electrons

An electron is a tiny particle with a negative charge. Electrons orbit the nucleus in atoms or ions.


Explain Electronic Structure

Electronic structure is a set of numbers to show the arrangement of electrons in their shells (or energy levels). For example the electronic structure of a potassium atom is 2,8,8,1


Define an element

An element is a substance made up of only one type of atom. It cannot be broken down chemically into any simpler substance.


What does empirical formula mean?

Empirical formula is the simplest ratio of elements in a compound.


Define emulsifier

An emulsifier is a substance which helps keep immiscible liquids (for example oil and water) mixed so that they do not separate out into layers.


Give me the meaning of emulsion

Emulsion is a mixture of liquids that do not dissolve in water.


Explain end point

End point is the point in a titration where the reaction is complete and titration should stop.


Define Ester

Ester is when a carboxylic acid is mixed with an alcohol .


What does Endothermic mean?

Endothermic is a reaction that takes in energy from the surroundings.


Define Energy level

Energy level is an area in an atom round its nucleus where the electrons are found


Explain Equilibrium

Equilibrium is the point in a reversible reaction in which the forward and backward rates of reaction are the same.
Therefore the amounts of substances present in the reacting mixture remain constant.


What does ethane mean?

Ethene is an alkene with the formula C₂H₄


Define Exothermic

Exothermic is a reaction that gives out energy to the surroundings.


Give me the meaning of fermentation?

Fermentation is the reaction in which the enzymes in yeast turns glucose into ethanol and carbon dioxide.


Define Flammable

Flammable is easily invited and capable of burning rapidly.


What does Fraction mean?

Fraction is hydrocarbons with a similar boiling point separated from crude oil.


Define Fractional Distillation

Fractional Distillation is a way to separate liquids from a mixture of liquids by boiling off the substances at different temperatures and then condensing and collecting the liquids.


Give me the meaning of Fullrene

Fullrene is a form of the element carbon that can form a large cage- like structure based on hexagonal rings of carbon atoms.


Define a functional group

Functional groups are an atom or a group of atoms that give organic compounds their characteristic reactions.


What does Gas Chromatography mean?

Gas Chromatography is the process of separating the components in a mixture by passing the vapours through a column and detecting them as they leave the column at different times.


Define Giant Covalent Structures.

Giant Covalent Structures are a huge 3D network of covalently bonded atoms (e.g the giant lattice of carbon atoms in diamond or graphite.


Explain Giant Lattice

Giant Lattice are a huge 3D network of atoms or ions (e.g the giant ionic lattice in sodium chloride).


Give me the meaning of Global Dimming.

Global Dimming is the reflection of sunlight by tiny solid particles in the air.


Define Global Warming

Global Warming is the increasing of the average temperature of the Earth.


What does Group mean?

Groups are all the elements in each column (labelled 1 to 7 and 0) down the Periodic table.


Explain hard water

Hard water is water in which it is difficult to form a lather with soap. It contains Calcium and/or Magnesium ions which react with soap to produce scum.


Define hardening

Hardening is the process of reacting plant oils with hydrogen to raise their melting point. This is used to make spreadable margarine.


What does mortar mean?

Motar is a building material used to bind bricks together. It is made by mixing cement and sand with water.


Define neutralisation

Neutralisation is when an acid reacts with a base they cancel each other out, and forms a salt and water.


Explain Nitrogen Oxides

Nitrogen Oxides are gaseous pollutants given off from motor vehicles. This is a cause of acid rain.


Define Pipette

A pipette is a tube used to measure accurate volumes of liquids.


What is a PH scale?

A PH scale is a number that shows how strongly acidic or alkaline a solution is. Acids have a PH value of less than 7 (PH 1 is strongly acidic). Alkalis have a PH value above 7 (PH 14 is strongly alkaline). A neutral liquid has s PH value of 7.


Explain what viscosity means?

Viscosity is the resistance of a liquid to flowing or the "thickness" or a resistance of a liquid to pouring.


Define Thermosoftening Polymers

A thermosoftening polymer is a polymer that forms plastics which can then be softened by heat. It is then remoulded into different shapes as they cool down and set.


What does universal indicator mean?

Universal Indicator is a mixture of indicators which can change through a range of colours depending on the PH of a solution. It's colour is matched to a PH number using a PH scale. It shows how strongly acidic or alkaline liquids and solutions are.


Define tectonic plates

Tectonic plates are the huge slabs of rock that make up the Earth's crust and top part of its mantle.


What does mantle mean?

The mantle is the layer of the earth between the crust and the Core.


Define mass spectrometer

A mass spectrometer is a machine that can be used to analyse small amounts of a substance to identify it and to find its relative molecular mass.


What does gradient mean?

Gradient is the change in Y / Change in X


Define percentage yield

Percentage yield is the actual mass of product collected in a reaction divided by the maximum mass that could have been formed in theory multiplied by 100.


What does phytomining mean?

Phytomining is the process of extraction of metals from ores using plants.


Define precipitate.

A precipitate is an insoluble solid formed by a reaction taking place in a solution.


What does reactant mean?

A Reactant is a substance we start with before a chemical reaction takes place.


Define Salt.

A salt is a compound formed when some or all of the hydrogen in an acid is replaced by a metal.


What does smelting mean?

Smelting is heating a metal ore in order to extract its metal.


Define Soapless Detergent

Soapless Detergent is a cleaning agent that does not produce scum when used with hard water.


What does Soft water mean?

Soft water is water containing no dissolved calcium and/ or magnesium salts so it easily forms a lather with soap.


Define stainless steel

Stainless steel is a chromium-nickel- alloy of steel which does not rust.


What does Steel mean?

Steel is an alloy of iron with small amounts of carbon or other metals such as nickel and chromium added.


Define hydrated

Hydrated describes a substance that contains water in its crystals.


What does ion- exchange column mean?

An ion- exchange column is a water softener which works by replacing calcium and magnesium ions with sodium or hydrogen ions. This removes the hardness.


Define scale (Limescale)

Scale is the insoluble substance formed when temporary hard water is boiled


What does shape memory alloy mean?

A shape memory alloy is a mixture of metals which respond to changes in temperature.