Glossary Flashcards
Accuracy
The degree to which a result conforms to the correct standard/value.
Precision
The degree to which results align with each other.
Reliability
The degree of certainty that a result is accurate.
Validity
Whether or not an experiment reflects or tests the research question.
Bias
Difference between the average of a large set of measurements and the true value.
Uncertainty
The degree of variation from one value to the next.
Personal error
Result from mistakes or misinterpretations of readings by the experimenter.
Systematic error
Errors in measurement varied by the same proportion from the true value (includes errors inherent to the experiment).
Random error
Errors in measurement that differ in proportion each time the experiment is conducted.
Pressure
The force of the gas on the walls of the vessel, per unit of surface area.
Chemical energy (enthalpy)
The energy contained within the various electric forces within and between species.
Thermal energy
Kinetic energy that manifests in the speed of randomly moving particles.
Activation energy (Ea)
The minimum energy required to commence a reaction.
Endothermic reaction
Has a net absorption of energy by the chemicals.
Exothermic reaction
Has a net release of energy by the reactants.
Fuel
A substance that can be reacted with other substances leading to the release of energy that can be harnessed for a specific purpose.
Greenhouse gasses
Gasses that absorb infra-red radiation, which warms the planet.
Renewable
Can be replenished at a rate quicker than it is consumed.
Viscosity
How resistant to flow a substance is.
Hygroscopic
Attracts water from the atmosphere.
Biogas
Fuel produced by the anaerobic breakdown of organic matter.
Bioethanol
Fuel produced by the fermentation of glucose in organic matter.
Biodiesel
Fuel produced by the esterification of the fats and oils in organic matter.
Complete combustion
Reaction of a substance with oxygen to produce CO2 and H2O.
Incomplete combustion
Partial burning of a substance to produce carbon monoxide (or solid carbon) and water.
Reduction
Gain of electrons.
Oxidation
Loss of electrons.
Conjugate redox pair
Reducing agent and its corresponding oxidizing agent.
Galvanic cell
An electrochemical cell in which chemical energy from spontaneous redox reactions is converted into electrical energy.
Standard half cell
A cell consisting of both members of the conjugate redox pair and an electrode at standard conditions.
Spontaneous reactions
Reactions that occur without an external energy source.
Direct redox reactions
Reactions where the chemical species react in the same vessel.
Indirect redox reactions
Reactions where chemical species react together in separate vessels.
Fractional distillation
The separation of a mixture into its component by heating them to a temperature at which one or more fractions of the mixture will vaporize.
Fuel cell
Electrochemical cell that continuously converts chemical energy into electrical energy by a redox reaction.
Porous electrode
A feature of fuel cells which maximises the ability for gaseous reactants to come into contact with the electrolyte.
Collision theory
For a chemical reaction to occur, the reactant particles must collide with sufficient energy and with the correct orientation.
Catalyst
A substance which increases the reaction rate without being consumed.
Heterogenous catalyst
A catalyst whose physical state differs from the phase of the reactants.
Homogenous catalyst
Catalyst whose physical state is the same as the phase of the reactants.
Transition state
The state corresponding to the highest energy point o an energy profile diagram during which bond breaking and forming is occurring.
Dynamic equilibrium
System in which the forwards and backwards reactions are occurring at the same rate.
Electrolytic reaction
Non-spontaneous redox reaction which requires energy to proceed.
Overpotential
The difference between the calculated potential required and actual potential required to facilitate an electrolytic reaction.
Primary cells
Non-rechargeable electrochemical cells.
Secondary cells
Rechargeable electrochemical cells.