Chemical TD & Flame Temp. Flashcards
The internal energy of a given substance is found to be dependent upon its ____, _____, & ______.
Temp, pressure, & state.
Pg. 1
The change in internal energy of a system that results from any physical change or chemical reaction depends only on _______.
The initial and final state of the system.
Pg. 1
What is the standard heat of formation?
The enthalpy of a substance in it’s standard state referred to its elements in their standards states at the same temperature.
Pg. 4
What is a “radical?”
An atom or molecule that has unpaired valence electrons (or an open electron shell).
Pg. 7
True or False
Because radicals have one or more dangling covalent bonds, that are highly reactive.
True
Pg. 7
What is a monopropellant?
A monopropellant is a chemical propulsion fuel which does not require a separate oxidizer.
Extra Notes: A rocket engine which is based on a monopropellant requires only one fuel line instead of a fuel and an oxidizer line.
Source: Wikipedia
What is the physical meaning of Enthalpy of Reaction?
The Heat of Reaction (also known and Enthalpy of Reaction) is the change in the enthalpy of a chemical reaction that occurs at a constant pressure. It is a thermodynamic unit of measurement useful for calculating the amount of energy per mole either released or produced in a reaction.
Source: ChemLib
A positive ΔHº value represents an _______ from the reaction (and from the surroundings), resulting in an________ reaction.
addition of energy
endothermic
Source: ChemLib
A negative value for ΔHº represents a _________ from the reaction (and into the surroundings) and so the reaction is ________.
removal of energy
exothermic
Source: ChemLib
What is a dislocation reaction?
A dissociation reaction is a chemical reaction in which a compound breaks apart into two or more components.
Source: Interwebs
What is enthalpy of formation (or heat of formation)?
Enthalpy of formation ( ΔH_f) is the enthalpy change for the formation of 1 mol of a compound from its component elements, such as the formation of carbon dioxide from carbon and oxygen.
Source: ChemLib
True or False
Dissociation reactions are endothermic.
True
Pg. 8
What is enthalpy wrt/ a TD system?
A thermodynamic quantity equivalent to the total heat content of a system. It is equal to the internal energy of the system plus the product of pressure and volume.
H = E + PV
Source: Interwebs
What are intensive properties?
Properties that do not depend on mass.
Pg. 9
What are extensive properties?
Properties that vary with the amount of mass in the system.
Pg. 9
What is the condition for equilibrium?
The entropy of the system has a max value for all possible configuration that are consistent with constant energy and volume.
Pg. 9
What is the partial pressure of a gas?
The partial pressure of a gas is the pressure that an individual gas in a mixture of gases would exert if it were by itself at the same temperature and volume.
Roger, Chem for Eng., Pg 100
What is a general definition for hydrocarbons?
compounds composed of carbon and hydrogen.
Lecture 2, Slide 15
Complete oxidation of simple hydrocarbon fuels forms ____ and ______.
Carbon dioxide (CO_2) and water (H_2O)
Lecture 2, Slide 15
What is the Stoichiometric Fuel-Air Ratio?
The exact ratio between fuel and air at which complete combustion takes place.
Lecture 2, Slide 15
What is the equivalence ratio?
The ratio of the actual fuel/air ratio to the stoichiometric
fuel/air ratio.
Lecture 2, Slide 17
Give the conditions that are present if the equivalence ratio is equal to one.
stoichiometric reaction; just the amount of oxidizer needed to completely burn a quantity of fuel.
Lecture 2, Slide 17
Give the conditions that are present if the equivalence ratio is less than one.
more than a stoichiometric quantity of oxidizer is supplied, the mixture is said to be (fuel) lean.
Lecture 2, Slide 17
Give the conditions that are present if the equivalence ratio is more than one.
less than a stoichiometric quantity of oxidizer is supplied, the mixture is said to be (fuel) rich.
Lecture 2, Slide 17
Rich or lean leads to ________.
lower net combustion heat release
Lecture 2, Slide 17
True or False
Enthalpy has meaning only when there is a group of molecules, a mole for instance; it is the ability of a group of molecules with internal energy to do PV work.
True
Lecture 2, Slide 21
True or False
A single molecule can have internal energy, but not enthalpy.
True
Lecture 2, Slide 21
What is the standard pressure value for the TD standard state?
The standard pressure value Po = 1.0 atm (101.325 kPa)
Lecture 2, Slide 22
What is the standard temperature value for TD standard state?
There is no standard temperature, but we generally use a reference temperature Tref = 25 oC or 298.15 K
Lecture 2, Slide 22
What is the heat enthalpy of formation?
The change of enthalpy when a chemical compound is formed isothermally from its stable elements at constant pressure.
Lecture 2, Slide 23
What is the zeroth law of TD?
If two systems are in thermodynamic equilibrium with a third system, the two original systems are in thermal equilibrium with each other.
Lecture 5, Slide 2
Entropy must _____ or _____ for any realistic process.
Increase
stay the same
Lecture 5, Slide 4
State the law of mass action.
For a chemical reaction mixture that is in equilibrium, the ratio between the concentration of reactants and products is constant.
Lecture 5, Slide 35
