Chemistry Keywords Flashcards

1
Q

Cathode

A

The negative electrode in electrolysis.

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2
Q

Neutral

A

A solution with a pH value of 7 which is neither acidic nor alkaline. Alternatively, something that carries no overall electrical charge

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3
Q

Particulate

A

Small solid particle given off from motor vehicles as a result of incomplete combustion of its fuel.

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4
Q

Reproducible

A

A measurement is reproducible if the investigation is repeated by another person, using different equipment and the same results are obtained.

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5
Q

Anhydrous

A

Describes a substance that does not contain water.

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6
Q

Formulation

A

A mixture that has been designed as a useful product.

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7
Q

Fermentation

A

The reaction in which the enzymes in yeast turn glucose into ethanol and carbon dioxide.

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8
Q

Endothermic

A

A reaction that takes in energy from the surroundings.

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9
Q

Reaction profile

A

The relative difference in the energy of reactants and products.

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10
Q

Double bond

A

A covalent bond made by the sharing of two pairs of electrons.

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11
Q

Rusting

A

The corrosion of iron.

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12
Q

Incomplete combustion

A

When a fuel burns in insufficient oxygen, producing carbon monoxide as a toxic product.

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13
Q

Order of magnitude

A

A comparison of the size of values. Two values are the same order of magnitude if their difference in size is small in comparison to other values being compared.

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14
Q

Thermosoftening polymer

A

Polymer that forms plastics which can be softened by heating, then remoulded into different shapes as they cool down and set.

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15
Q

Mean

A

The arithmetical average of a series of numbers.

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16
Q

Fullerene

A

Form of the element carbon that can exist as large cage-like structures, based on hexagonal rings of carbon atoms.

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17
Q

Mass number

A

The number of protons plus neutrons in the nucleus of an atom.

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18
Q

Delocalised electron

A

Bonding electron that is no longer associated with any one particular atom.

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19
Q

Polymer

A

A substance made from very large molecules made up of many repeating units (monomers).

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20
Q

Risk

A

The likelihood that a hazard will actually cause harm.

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21
Q

Categoric variable

A

Categoric variables have values that are labels. For example types of material.

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22
Q

Mixture

A

When some elements or compounds are mixed together and intermingle but do not react together (i.e. no new substance is made). A mixture is not a pure substance.

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23
Q

Saturated hydrocarbon

A

Describes a hydrocarbon with only single bonds between its carbon atoms. This means that it contains as many hydrogen atoms as possible in each molecule.

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24
Q

Alloy

A

A mixture of two or more elements, at least one of which is a metal.

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25
Q

Reactivity series

A

A list of elements in order of their reactivity.

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26
Q

Electronic structure

A

A set of numbers to show the arrangement of electrons in their shells (or energy levels).

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27
Q

Ore

A

Ore is rock which contains enough metal to make it economically worthwhile to extract the metal.

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28
Q

Strong acids

A

These acids completely ionise in aqueous solutions.

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29
Q

Viscosity

A

The resistance of a liquid to flowing or pouring; a liquid’s ‘thickness’

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30
Q

Fair test

A

A fair test is one in which only the independent variable has been allowed to affect the dependent variable.

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31
Q

Distillation

A

Separation of a liquid from a mixture by evaporation followed by condensation.

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32
Q

Unsaturated hydrocarbon

A

A hydrocarbon whose molecules contains at least one carbon–carbon double bond.

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33
Q

Reactant

A

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

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34
Q

Independent variable

A

The variable for which values are changed or selected by the investigator.

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35
Q

Stainless steel

A

A chromium-nickel alloy of steel which does not rust.

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36
Q

Shell

A

An area in an atom, around its nucleus, where electrons are found.

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37
Q

Displacement reaction

A

A reaction in which a more reactive element takes the place of a less reactive element in one of its compounds or in solution.

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38
Q

Quantitative data

A

Data that is numerical or a measurement.

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39
Q

Ratio

A

A way of comparing two or more quantities, showing how many times one quantity is contained within the other.

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40
Q

Bond energy

A

The energy required to break a specific chemical bond.

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41
Q

Fraction

A

Hydrocarbons with similar boiling points separated from crude oil.

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42
Q

Alkali metal

A

Elements in Group 1 of the periodic table which have 1 electron in their outer shell.

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43
Q

Hydrocarbon

A

A compound containing ONLY hydrogen and carbon.

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44
Q

Retention factor

A

A measurement from chromatography: it is the distance a spot of substance has been carried above the baseline divided.

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45
Q

Nanoscience

A

The study of very tiny particles or structures between 1 and 100 nanometres in size – where 1 nanometre = 0.000000001 metres.

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46
Q

Covalent bond

A

The bond between two atoms that share one or more pairs of electrons.

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47
Q

Collision theory

A

An explanation of chemical reactions in terms of reacting particles colliding with sufficient energy for a reaction to take place.

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48
Q

Carbon steel

A

Alloy of iron containing controlled, small amounts of carbon.

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49
Q

Inert

A

Unreactive.

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50
Q

Fractional distillation

A

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

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51
Q

Mole

A

The amount of substance in the relative atomic or formula mass of a substance in grams.

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52
Q

Neutron

A

A dense particle found in the nucleus of an atom. It is electrically neutral, carrying no charge.

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53
Q

Atom economy

A

A measure of the amount of starting materials that end up as useful products.

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54
Q

Continuous variable

A

Can have values (called a quantity) that can be given by measurement (for example, mass, volume, temperature, etc.).

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55
Q

Significant figures (s.f.)

A

The important digits within a number. All non-zero digits are significant. Zeros may be significant if followed by another nonzero digit.

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56
Q

Le Châtelier’s Principle

A

When a change in conditions is introduced to a system at equilibrium, the position of equilibrium shifts so as to cancel out the change.

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57
Q

Relative atomic mass

A

The average mass of the atoms of an element compared with carbon-12 (which is given a mass of exactly 12). The average mass must take into account the proportions of the naturally occurring isotopes of the element.

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58
Q

Qualitative data

A

Data that is descriptive or categorical.

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59
Q

Galvanised

A

Iron or steel objects that have been protected from rusting by a thin layer of zinc metal at their surface.

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60
Q

Isotope

A

Atoms that have the same number of protons but different number of neutrons, i.e., they have the same atomic number but different mass numbers.

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61
Q

Homologous series

A

A group of related organic compounds that have the same functional group.

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62
Q

Base

A

The oxide, hydroxide, or carbonate of a metal that will react with an acid, forming a salt as one of the products. (If a base dissolves in water it is called an alkali). Bases are proton (H+ ion) acceptors.

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63
Q

Recycle

A

The process in which waste materials are processed to be used again.

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64
Q

Balanced symbol equation

A

A symbol equation in which there are equal numbers of each type of atom on either side of the equation.

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65
Q

Control group

A

If an experiment is to determine the effect of changing a single variable, a control is often set up in which the independent variable is not changed, thus enabling a comparison to be made. If the investigation is of the survey type a control group is usually established to serve the same purpose.

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66
Q

Respiration

A

The process by which food molecules are broken down to release energy for the cells.

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67
Q

Precipitate

A

An insoluble solid formed by a reaction taking place in solution.

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68
Q

Hypothesis

A

A proposal intended to explain certain facts or observations.

69
Q

Relative formula mass Mr

A

The total of the relative atomic masses, added up in the ratio shown in the chemical formula, of a substance.

70
Q

Filtration

A

The technique used to separate substances that are insoluble in a particular solvent from those that are soluble

71
Q

Climate change

A

The change in global weather patterns that could be caused by excess levels of greenhouse gases in the atmosphere.

72
Q

Directly proportional

A

A relationship that, when drawn on a line graph, shows a positive linear relationship that crosses through the origin.

73
Q

Atomic number

A

The number of protons (which equals the number of electrons) in an atom. It is sometimes called the proton number.

74
Q

Equilibrium

A

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

75
Q

Intermolecular forces

A

The attraction between the individual molecules in a covalently bonded substance.

76
Q

Line of best fit

A

A line that represents the general trend of data.

77
Q

pH

A

A number which shows how strongly acidic or alkaline a solution is

78
Q

Transition element

A

Element from the central block of the periodic table

79
Q

Halogens

A

The elements found in Group 7 of the periodic table. They have 7 electrons in their outer shell.

80
Q

Gradient

A

All the elements in the columns (labelled 1 to 7 and 0) in the periodic table.

81
Q

Word equations

A

A way of describing what happens in a chemical reaction by showing the names of all reactants and the products they form.

82
Q

Nucleus (of an atom)

A

The very small and dense central part of an atom that contains protons and neutrons.

83
Q

Range

A

The maximum and minimum values of the independent or dependent variables.

84
Q

Oxidised

A

Describes a substance that has had oxygen added to it / or has lost electrons.

85
Q

Electrical (chemical) cells

A

Contain chemicals that react to produce electricity.

86
Q

Dependent variable

A

The variable for which the value is measured for each and every change in the independent variable.

87
Q

Sacrificial protection

A

An effective way to prevent rusting whereby a metal more reactive than iron (such as zinc or magnesium) is attached to or coated on an object.

88
Q

Percentage yield

A

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

89
Q

Prediction

A

A forecast or statement about the way something will happen in the future.

90
Q

Ionic equation

A

An equation that shows only those ions or atoms that change in a chemical reaction.

91
Q

Exothermic

A

A reaction that transfers energy to the surroundings.

92
Q

Ceramics

A

Materials made by heating clay, or other compounds, to high temperatures (called firing) to make hard, but often brittle, materials, which make excellent electrical insulators.

93
Q

Accurate

A

A measurement is considered accurate if it is judged to be close to the true value.

94
Q

Diffusion

A

The automatic mixing of liquids and gases as a result of the random motion of their particles.

95
Q

Hydrated

A

Describes a substance that contains water in its crystals.

96
Q

Electron

A

A tiny particle with a negative charge. Electrons orbit the nucleus of atoms or ions in shells.

97
Q

Compound

A

A substance made when two or more elements are chemically bonded together.

98
Q

Product

A

A substance made as a result of a chemical reaction.

99
Q

Chromatography

A

The process whereby small amounts of dissolved substances are separated by running a solvent along a material such as absorbent paper.

100
Q

Alkane

A

Saturated hydrocarbon with the general formula CnH2n+2.

101
Q

Variable

A

Physical, chemical or biological quantity or characteristic.

102
Q

Titration

A

A method for measuring the volumes of two solutions that react together.

103
Q

Alkene

A

Unsaturated hydrocarbon which contains a carbon–carbon double bond. Its general formula is CnH2n.

104
Q

Covalent bonding

A

The attraction between two atoms that share one or more pairs of electrons.

105
Q

Valid

A

Suitability of the investigative procedure to answer the question being asked.

106
Q

Half equation

A

An equation that describes reduction (gain of electrons) or oxidation (loss of electrons).

107
Q

Reversible reaction

A

A reaction in which the products can re-form the reactants.

108
Q

Biodegradable

A

Materials that can be broken down by microorganisms.

109
Q

Burette

A

A long glass tube with a tap at one end and markings to show volumes of liquid; used to add precisely known volumes of liquids to a solution in a conical flask below it.

110
Q

Life cycle assessment

A

Carried out to assess the environmental impact of products, processes or services at different stages in their life cycle.

111
Q

Standard form

A

A way of displaying large and small numbers.

112
Q

Closed system

A

A system in which no matter enters or leaves.

113
Q

Data

A

Information, either qualitative or quantitative, that has been collected.

114
Q

Blast furnace

A

The huge reaction vessels used in industry to extract iron from its ore.

115
Q

Continuous data

A

Continuous data Data that can take any value.

116
Q

Avagadro constant

A

The number of atoms, molecules, or ions in a mole of any substance.

117
Q

Ion

A

A charged particle produced by the loss or gain of electrons

118
Q

State symbol

A

The abbreviations used in balanced symbol equations to show if reactants and products are solid (s), liquid (l), gas (g) or dissolved in water (aq).

119
Q

End point

A

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

120
Q

Oxidation

A

The reaction when oxygen is added to a substance / or when electrons are lost.

121
Q

Flammable

A

Easily ignited and capable of burning rapidly.

122
Q

Thermosetting polymer

A

Polymer that can form extensive cross-linking between chains, resulting in rigid materials which are heat-resistant.

123
Q

Giant lattice

A

A huge 3D network of atoms or ions.

124
Q

Relationship

A

The link between the variables that were investigated.

125
Q

Proton

A

A tiny positive particle found inside the nucleus of an atom.

126
Q

Fuel cells

A

Sources of electricity that are supplied by an external source of fuel.

127
Q

Non-renewable

A

Something which cannot be replaced once it is used up.

128
Q

Repeatable

A

A measurement is repeatable if the original experimenter repeats the investigation using the same method and equipment and obtains the same or precise results.

129
Q

Control variable

A

A variable which may, in addition to the independent variable, affect the outcome of the investigation and therefore has to be kept constant or at least monitored.

130
Q

Giant covalent structure

A

A huge 3D network of covalently bonded atoms.

131
Q

Atmosphere

A

The relatively thin layer of gases that surround planet Earth.

132
Q

Precise

A

A precise measurement is one in which there is very little spread about the mean value. Precision depends only on the extent of random errors – it gives no indication of how close results are to the true (accurate) value.

133
Q

Cracking

A

The reaction used in the oil industry to break down large hydrocarbons into smaller, more useful ones.

134
Q

Electrolysis

A

The breakdown of a substance containing ions by electricity.

135
Q

Periodic table

A

An arrangement of elements in the order of their atomic numbers, forming groups and periods.

136
Q

Alkali

A

Its solution has a pH value more than 7.

137
Q

Anode

A

The positive electrode in electrolysis.

138
Q

Functional group

A

An atom or group of atoms that give organic compounds their characteristic reactions

139
Q

Composites

A

Materials made of two or more different materials, containing a matrix or binder surrounding and binding together fibres or fragments of another material which acts as the reinforcement.

140
Q

Dot and cross diagram

A

A drawing to show only the arrangement of the outer shell electrons of the atoms or ions in a substance.

141
Q

Monomers

A

Small reactive molecules that react together in repeating sequences to form a very large molecule (a polymer).

142
Q

Carbon footprint

A

The total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event.

143
Q

Atom

A

The smallest part of an element that can still be recognised as that element.

144
Q

Flame emission spectroscopy

A

A method of instrumental analysis in which the light given off when a sample is placed in a flame produces characteristic line spectra to identify and measure the concentration of metal ions in the sample.

145
Q

Molecular formula

A

The chemical formula that shows the actual numbers of atoms in a particular molecule.

146
Q

Catalyst

A

A substance that speeds up a chemical reaction by providing a different pathway for the reaction that has a lower activation energy. The catalyst is chemically unchanged at the end of the reaction.

147
Q

Discrete data

A

Data that can only take certain values.

148
Q

Universal indicator

A

A mixture of indicators that can change through a range of colours to show how strongly acidic or alkaline liquids and solutions are.

149
Q

DNA (deoxyribonucleic acid)

A

A large organic molecule that encodes genetic instructions for the development and functioning of living organisms and viruses.

150
Q

Aqueous solutions

A

The mixture made by adding a soluble substance to water.

151
Q

Activation energy

A

The minimum energy needed for a reaction to take place.

152
Q

Neutralisation

A

The chemical reaction of an acid with a base in which a salt and water are formed. If the base is a carbonate or hydrogen carbonate, carbon dioxide is also produced in the reaction.

153
Q

SI system of units

A

A system of units for physical quantities that are considered the standard units.

154
Q

Noble gases

A

The very unreactive gases found in Group 0 of the periodic table. Their atoms have very stable electronic structures.

155
Q

Reduction

A

A reaction in which oxygen is removed or electrons are gained.

156
Q

Element

A

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

157
Q

Weak acids

A

Acids that do not ionise completely in aqueous solutions

158
Q

Electrolyte

A

A liquid, containing free-moving ions, which is broken down by electricity in the process of electrolysis.

159
Q

Catalytic converter

A

Fitted to exhausts of vehicles to reduce pollutants released.

160
Q

Pipette

A

A glass tube used to measure accurate volumes of liquids.

161
Q

Salt

A

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

162
Q

Biofuel

A

Fuel made from animal or plant products.

163
Q

Line graph

A

Used when both variables are continuous. The line should normally be a line of best fit, and may be straight or a smooth curve.

164
Q

Hazard

A

A hazard is something (e.g., an object, a property of a substance or an activity) that can cause harm.

165
Q

Anomalies

A

Results that do not match the pattern seen in the other data collected or are well outside the range of other repeat readings (outliers).

166
Q

Ionic bond

A

The electrostatic force of attraction between positively and negatively charged ions.

167
Q

Law of the conservation of energy

A

The total mass of the products formed in a reaction is equal to the total mass of the reactants.

168
Q

Acid

A

When dissolved in water, its solution has a pH value less than 7. Acids are proton (H+ ion) donors.

169
Q

Thermal decomposition

A

The breakdown of a compound by heating it.