aqa as level unit 1 definitions


What is the mass number?

Number of protons and neutrons in the nucleus of an atom

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what is the atomic number?

Number of protons in the nucleus of an atom.

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what is a mass spectromete?

An analytical technique that produces a finger print specific to a molecule and identifies compounds present in a sample

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What is the relative atomic mass?

The average mass of an atom relative to 1/12 the mass of a carbon-12 atom.

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what is the relative molecular mass?

Mr- mass of a molecule relative to 1/12 the mass of a carbon-12 atom.

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What is the equation for atom economy?

Mass of desired product / total mass of reactants x100

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What is a mole?

Amount of a substance that has the same number of particles as there are atoms in 12g of carbon-12.

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What is Avogadros number?

- there are 6.022 x 10 to power of 23 atoms in 12g of carbon-12

-one mole of any specific entity contains 6.022 x 10 power of 23 of that entity.

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What is molecular formula?

The actual number of atoms of each element in a molecule.

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What is the Empirical formula?

the simplest whole number ratio of atoms of each element in a compound.

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What is the relative isotopic mass?

mass of an atom of an isotope compared with 1/12 the mass of an atom of carbon-12

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Whar is the first ionisation energy?

Energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions.

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What is the second ionisation energy?

The amount of energy required to remove one electron from each of one mole of gaseous unipositive ions of that element.

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What are isotopes?

Atoms with the same atomic number but different mass number

(same number of protons but different number of neutrons)

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Describe the chemical and physical properties of i

1. No difference in chemical properties due to number of electrons being the same in different isotopes. Similar chemical properties because they have the same electronic structure.

2. Slightly varying physical properties due to different masses.

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what is a covalent bond?

A shaired pair of electrons

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What is an ionic bond?

The electrostatic force of attraction between oppositey charged ions.

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What is electronegativity?

the relative ability of an element to attract electrons in a bond.

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Describe polarity in covalent bonds

The unequal sharing of electrons between atoms covalently bonded together.

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what is a co-ordinate bond?

a covalent bond formed when the pair of electrons originate from one atom

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What is a metallic bond?

Atoms linked together by the migration of electrons from atom to atom

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What is a metallic crystal?

a lattice of positive ions in a sea of delocalised electrons.

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What is a hydrocarbon?

A compound consisting of hydrogen and carbon only.

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what does saturated mean?

A hydrocarbon that contains single C-C bonds

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What is an unsaturated Hydrocarbon?

Hydrocarbon that only contains double C=C bonds.

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What are Alkanes? give examples.

A class of hydrogcarbons in which atoms are connected by single bonds only.






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What are alkenes? give examples

Unsaturated hydrocarbons with double C=C bonds. E.g. ethene butene, propene, hexene

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What is the homologous series?

a family of organic molecules which all contain the same functional group, but have an increasing number of carbon atoms.

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What is a functional group?

Group of atoms that determine the chemical and physical properties and naming of a class of organic compounds.

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what are structural isomers?

Isomers which have the same molecular formula but differnt structures. It gives molecules different chemical and physical properties.

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What are chain isomers?

Structural isomers which occur when there are two or more ways of arranging the carbon skeleton of a molecule.

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What are functional group isomers?

Structural isomers which contain different functional groups.

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What are position isomers?

structural isomers which have the same carbon skeleton and same functional groups but in which the functional groups are joined at different places on the Carbon skeleton.

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what are intermolecular forces? Name three.

intermolecular forces are weak attractive forces that occur between molecules.

Van der waals forces

Dipole-dipole bonds

Hydrogen bonds

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Where do permanent dipole-dipole bonds act?

between all molecules with permanent dipoles.

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What is thermal cracking?

Cracking using high temperatures and pressures.

produces mostly alkenes and hydrogen

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What is fractional distillation?

the separation of the components in a liquid mixture into fractions which differ by boiling points and hence chemical composition; by means of distillation, typically using a fractioning column 

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What is cracking?

Occurs when larges alkanes are broken into smaller molecules.

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What is catalytic cracking?

cracking using a zeolite catalyst with low pressures and temperatures. produces more branched cyclic and aromatic hydrocarbons.

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What is a catalytic converter?

It is used in car engines.

Contains catalysts capable of converting harmful gaseous products into less harmful ones.

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What is the difference between complete and incomp

Complete combustion: occurs when there is a lot of oxygen. produces CARBON DIOXIDE and WATER.

Incomplete combustion: occurs when there is a limited supply of oxygen. Produces CARBON MONOXIDE, WATER       o r        CARBON and WATER.

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