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AS Chem Glossary
Key words for AQA AS Chemistry
Question | Answer |
---|---|
What does Acid rain consist of? | Quantities of Carbonic, Nitric and Sulfuric Acids. |
Define 'Atomic Number' | The number of Protons in the nucleus of an Atom |
What is the avagadro's constant? | 6.022 x 10 23rd particles mol -1 |
Describe the Catalytic Cracking proccess. | Occurs when the energy required for bond breaking in Hydrocarbons is provided by heat, in the presence of a catalyst. |
Describe the Thermal Cracking process. | Occurs when the energy required for bond breaking in hydrocarbons is provided by heat. |
What are Chain Isomers? | Structural Isomers which occur when there are two or more ways of arranging the carbon skeleton of a molecule. |
What is the formula for working out concentration? | Number of moles of solute/volume of solution in dm3 = with units mol dm-3 |
What is a co-ordinate bond? | A covalent bond formed when the pair of electrons originate from one atom. |
Describe a covalent bond. | A bond which involes a shared pair of electrons between two atoms. |
What is the Cracking proccess? | Occurs when large Alkanes are broken into smaller molecules. |
What is Electronegativity? | The power of an atom to attract the shared electrons in a covalent bond. |
What is the Empirical formula? | The SIMPLEST ratio of atoms of each element in a compound. |
What is Enthalpy change? | The amount of heat energy released or absorbed when a chemical or physical change occurs at constant pressure. |
What is 'Enthalpy of fusion'? | The enthalpy required to change one mole of a solid into a liquid. X(s) -> X(l) |
What is Enthalpy of vaporisation? | The enthalpy required to change one mole of a liquid into a gas. X(l) -> X(g) |
Define the first ionisation energy. | The enthalpy change for the removal of one mole of electrons from one mole of atoms of an element in the gas phase. X(g)->X+(g) +e- |
What is a functional group? | An atom or group of atoms which, when present in different molecules, causes them to have similar chemical properties. |
What are functional group isomers? | Structural isomers which contain different functional groups. |
Describe a Giant Ionic lattice/Ionic crystal. | A laticem of positive and negative ions bound together by electrostatic attractions. |
Describe a Giant metallic lattice/Metallic crystal. | A lattice of metal ions surrounded by delocalised electrons. |
What are greenhouse gases? | Gases in the atmosphere which absorb infra-red radiation (e.g water vapour, carbon dioxide, methane and ozone). |
What are the Homologous series? | A family of organic molecules which all contain the same functional group, but have an increasing number of carbon atoms. |
What is hydrogen bonding? | An intermolecular force between the lone pair on an electronegative atom (N, O or F) and a hydrogen atom bonded to such an electronegative atom. |
What counts as an 'Ideal Gas'? | One that obeys the idea gas equation, pv=nRT |
What is an ionic bond? | The Electrostatic force of attraction between opositely charged ions. |
Describe an Ion. | An atom or group of atoms which has lost or gained one r more electrons, giving it a negative or positive charge. |
What are 'Isomers'? | Molecules with the same chemical formula, but in which the atms are arranged differently. |
What are 'Isotopes'? | Atoms of the same element with the same atomic number but different mass numbers. |
Describe a macromolecular (giant) Crystal | A large, covalently bonded lattice structure. |
Definw a macromolecule. | A large molecule. |
What does the mass number (A) represent? | The total number of protons and neutrons in the nucleus of one atom of the element. |
Describe metallic bonding. | Elecrostatic atteaction between metal ions and delocalised electrons. |
What is a 'mole'? | A quantity of particles. 1 mole is 6.022 x 10 23rd particles. |
What is the molecular formula? | The actual numbers of atoms in each element in a molecule. |
What do neutral atoms contain? | The same number of protons and electrons. |
What are 'orbitals'? | Volumes in space around the nucleus within which electrons are most likely to be found. |
What is the equation for 'Percentage atom economy'? | [Mass of desired product/total mass of reactants]x100 |
What is the definition of 'percentage atom economy'? | A measure of how much of a desired product in a reaction is formed from the reactants. |
What is 'Percentage yield'? | It is a practical measure of the effciency of a reaction. |
What is the equation for percentage yield? | [Actual mass of product/maximum mass of products] x 100 |
What is 'Polarity'? | It is the displacement of electron density (formation of an electric dipole) in a covalent bond, orin a moleule, due to a difference in electronegativity. |
What are position isomers? | Structural isomers which have the same carbon skeleton and the same functional group, but the functional group is in a different place on the chain. |
What is the formula for relative atomic mass (Ar)? | Average mass of one atom of an element/1/12 x the mass of one atom of C12 |
What is the formula for relative molecular mass (Mr)? | Average mass of one molecule/ 1/12 x the mass of one atom of C12 |
What are saturated Hydrocarbons? | They contain C-C single bonds and C-H bonds. |
What is a 'Square Planar'? | The spatial arrangement of a central aom surrounded by four atoms situated at the corners of a square. |