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Flashcards in Definitions Deck (104):
1

Actual yield

The amount of product obtained

2

Theoretical yield

Maximum amount of product that could theoretically be obtained

3

Percentage yield

Actual yield described as % of theoretical yield

4

Rate or reaction

Speed at which a reaction takes place. Mesured by rate at which product is formed or reactants used.

5

Catalyst

Substance that speeds up a reaction without being changed or used up itself.

6

Element

Pure substance containing one type of atom

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Compound

Substances containing two or more elements chemicaly combined

8

Mixture

Two or more substances mixed together but not chemicaly combined

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Molecule

Group of atoms of one or more elements chemicaly combined with a finite number of atoms

10

Alloy

Other elements mixed with a metal to give it useful properties

11

Atom

Smallest particle of an element

12

Electron shell

Regions occupied by electrons around the nucleus

13

Electron structure

Show the number of electrons in each she'll 2,8,8

14

Periodic table

Shows elements in order of atomic number

15

Groups

Vertical columns of periodic table

16

Periods

horizontal rows of periodic table

17

Formula

Shows ratio / number of atoms of each element in a compound or molecule

18

Law of conservation of mass

Total mass of products equals total mass or reactants in any chemical reaction

19

Balanced chemical equation

Total number of atoms of each element are equal on either side of a chemical equation

20

Ore

Rock or mineral containing enough metal to make extraction economic

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Phytomining

Extraction of metals from plant ash

22

Bioleaching

Extraction of metal from low grade ores using bacteria or fungi

23

Global warming

Gradual rising of temperature of the atmosphere

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Global dimming

When polluting particles prevent a proportion of sunlight from penetrating the atmosphere

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Greenhouse gas

Gas in the atmosphere which prevents reflected Ray's from the sun from leaving the atmosphere

26

Catalytic converter

A box on the exhaust containing platinum which helps convert nitrogen oxides to nitrogen and oxygen

27

Flu gas scrubber

Contains calcium hydroxide which reacts with sulphur dioxide in factory chimneys to prevent its release into the atmosphere

28

Alkanes

Hydrocarbons with general formula CnH2n+2

29

Viscosity

How easily a liquid can flow

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Fraction

Contains a mixture of compounds with molecules of similar size and boiling point

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Chemical bond

Holds two atoms together after a reaction

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Ionic bond

A bond between a metal and a non metal. held together by strong electrostatic forces of attraction between positive and negative ions

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Covalent bond

A bond between 2 non metals. Electrons are shared

34

Structural formula

A diagram which shows which atoms are bonded to which

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Electronic theory

States that when atoms react, they lose gain or share electrons to become stable

36

Giant ionic lattice

A regular structure made from oppositely charged ions

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Valency

Number of electrons available for bonding, ionically or covalently

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Simple molecule

Small molecules with covalent bonds and just a few atoms

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Intermolecular forces

Weak attractive forces between molecules

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Giant covalent structure

Large numbers of atoms joined by covalent bonds

41

Allotropes

Different crystalline forms of the same material, e.g. Graphite and diamond are allotropes of carbon

42

Fullerene

An allotrope of carbon

43

Buckyballs

A fullerene with formula C60 shaped like a football

44

Giant metallic structure

Positive metal ions surrounded by a sea of delocalised electrons

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Malleable

Property of metal meaning it can be shaped

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Memory metal

Metal alloy that returns to its original shape when heated

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Polymer

Molecule made up of many repeating units or monomers

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Monomer

Simple molecule that joins with many others to make a polymer

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Thermosetting

Rigid material that has a fixed shape

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Thermosoftening

Material that softens under heat and can be reshaped

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Nanotechnology

Working with atoms and molecules 1nm - 100nm in size

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Nanoparticles

Very small particles 1 - 100nm long

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Atomic number

Number of protons in an atom

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Mass number

Number of protons and neutrons in an atom

55

Mass spectrometer

Instrument to sort particles and measure their relative mass

56

Relative atomic mass

Mass of atoms of elements relative to 12C

57

Mole

A large number -6x10:23 A mole of a substance weighs the relative atomic or molecular mass in grams

58

Isotopes

Atoms of an element with different numbers of neutrons but the same number of protons and electrons

59

Relative formula mass

Combined relative atomic masses of atoms in a formula

60

Empirical formula

Simplest ratio of atoms of each element in a compound

61

Reversible reaction

Reaction in which products can react or fall apart to form the reactants

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Alkene

Hydrocarbons with General formula CnH2n

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Saturated hydrocarbon

Has no double bonds

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Unsaturated hydrocarbon

Has at least one double bond

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Carbon neutral

CO2 released into the atmosphere on burning is the same as CO2 extracted from the atmosphere due to photosynthesis

66

Hydration of ethene

Method of adding hydrogen to ethene to make ethanol

67

Fermentation

Method of producing ethanol from plant sugars

68

Monomer

Small molecule that can bond to form a large molecule called a polymer

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Polymer

Large molecule made from thousands of monomers

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Smart polymers

New polymers with special properties

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Shape memory alloys / polymers

Materials that have a memory and return to Thais original shape on heating

72

Emulsion

Two immiscible liquids e.g. Oil and water , which are bound together

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Immiscible

Do not mix

74

Hydrophilic

Water loving, will bind with water

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Hydrophobic

Water hating, will bind with oil

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Hydrogenation

Method of turning liquid oils into spreadable fats by adding hydrogen at 60*c with a nickel catalyst

77

Triglycerides

Structure of plant oils which have three hydrocarbon chains attached to a glycerol based molecule

78

Biodiesel

Diesel fuel made from plant oil e.g. Rapeseed oil

79

Crust

Outer layer of earth

80

Mantle

Layer of denser rock between crust and core

81

Core

Centre of earth made of nickel and iron

82

Continental drift

Slow movements of continents over millions of years

83

Convection currents

Movement of the mantle due to heat caused by radiation

84

Tectonic plates

Vast pieces of crust and upper mantle witch have cracked into pieces

85

Primordial soup

Mixture of basic chemicals made by Miller and Urey from wich organisms could develop

86

Magnetic stripes

Reflected pattern of magnetism in rocks on eather side of the mid Atlantic ridge

87

Exothermic reaction

Gives out energy to the surroundings

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Endothermic reaction

Takes in energy from the souroundinig

89

Crystal

Regular solid lattice. It has sharp edges and flat sides

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Acid

Releases H+ ions and has a ph <7

91

Alkali

Soluble base that releases OH- ions and has a pH of >7

92

Base

Neutralises an acid to make a salt and water

93

Displacement reaction

Reaction where a more reactive element displaces displaces a less reactive one from a compound

94

Precipitate

Insoluble solid product of a reaction

95

Precipitation reaction

Reaction between two solutions to produce a precipitate

96

Electrolysis

Splitting a chemical solution or molten liquid using electricity

97

Electrolyte

Liquid that carries current and undergoes a chemical change

98

Electrode

Connection between electric circuit and electrolyte

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Anode

Positive electrode

100

Cathode

Negative electrode

101

Half equation

Describes what happens at one of the electrodes during electrolysis

102

Oxidation

Loss of electrons

103

Reduction

Gain of electrons

104

Electroplating

Using electrolysis to deposit metal on a materia