CHAPTER 8- CHEMICAL REACTIVITY Flashcards
What was the main conclusion of the 2002 U.S. Chemical Safety and Hazard Investigation Board (CSB) report on reactive chemical hazards?
B) Reactive chemical incidents are a significant safety problem.
What caused the explosion at T2 Laboratories in December 2007?
B) A runaway reaction due to inadequate heat removal from a reactor
What is a runaway reaction?
B) A reaction where the temperature rises rapidly due to uncontrolled heat generation
According to the CSB’s investigation, why were the engineers at T2 Laboratories unable to prevent the 2007 explosion?
A)They were not trained to recognize reactive chemical hazards.
What is the definition of a chemical reactivity hazard?
C) A situation with the potential for an uncontrolled chemical reaction that can cause serious harm
What does the acronym CHETAH stand for in the context of predicting reactive chemical hazards?
B) Chemical Thermodynamics and Energy Release Evaluation
What happens to the internal temperature of a reactor when there is greater heat loss through the walls?
A) The internal temperature decreases.
What is meant by “adiabatic conditions” in the context of reactor behavior?
D) When there is no heat transfer between the reactor and its surroundings
Why do larger reactor vessels behave more like adiabatic systems?
B) Because the surface-to-volume ratio decreases, reducing heat loss through the walls
What is one major reason scaling up reactions from laboratory size to large commercial reactors can lead to safety incidents?
C) Self-heating rates become significantly higher, leading to uncontrollable temperature rises.
What is the primary purpose of a calorimeter in a lab setting?
B) To safely test small amounts of material and study chemical reactions
Which company contributed significantly to the development of calorimeter technology in the 1970s?*
B) Dow Chemical
What is the main goal of achieving adiabatic conditions in calorimetry?
B) To prevent any heat loss from the system
In which calorimeter mode is a sample gradually heated at a constant rate to detect a reaction’s heat?
C) Thermal scan mode
Which calorimeter uses a thin-walled glass cell, resulting in low thermal inertia?
D) ARSST
Which calorimeter is best suited for studying chemicals with delayed reactions?
A) ARC
What is the phi-factor in calorimetry used to represent?
B) The thermal inertia of the calorimeter system
What is a characteristic of the DSC (Differential Scanning Calorimeter)?
A) It uses an open system exposed to the atmosphere.
Which calorimeter is ideal for testing reactions with very low heating rates?
C) ARC
What is indicated by the increase in pressure after a reaction has finished in an APTAC test?
B) Possible decomposition of one of the reaction products
How does the heat capacity of the sample vessel affect the accuracy of calorimetric measurements?
C) It ensures that all heat is accounted for in the measurements
Which of the following is essential for calculating the heat transferred in a calorimetric experiment?
D) All of the above
How is the heat capacity of a calorimeter typically determined?
A) By measuring the temperature change of a known mass of water
In a calorimetric experiment, what does a negative value of heat (q) indicate?
B) Exothermic process
Why is it important to adjust calorimeter data for the heat capacity of the sample vessel?
A) To ensure accurate measurement of the heat transferred
Which equation is used to calculate the heat transferred in a calorimetric experiment?
A) ( q = mc\Δ T )
What does the symbol ( ΔT ) represent in calorimetry?
B) Change in temperature
If the heat capacity of the sample vessel is not considered, how will it affect the results?
B) The results will be less accurate
What is the unit of heat capacity?
B) Joules per degree Celsius
What is the specific heat capacity of a substance?
A) The amount of heat required to raise the temperature of 1 gram of the substance by 1°C
What type of reaction system where non-condensable gases are produced but the heat of vaporization of the liquid does not always dominate during the entire relief discharge?
B) Hybrid/non-tempered reaction
What type of reaction system where non-condensable gases are produced as a result of the reaction?
D) Hybrid/tempered reaction
What type of reaction system where tempered reactions are inherently safer since the cooling mechanism is part of the reaction mass?
A) Volatile/tempered reaction
The reaction produces non-condensable gases and the liquid is not volatile enough for the heat of vaporization of the liquid to have much effect during the entire relief discharge.
C) Gassy/non-tempered reaction
Type of data is used to design and operate processes so that reactive chemical incidents occur.
C) Calorimeter data
It can be used to estimate the heat of reaction of the reacting sample.
C) Calorimeter data
This analysis provide additional information beyond the kinetic model analysis discussed.
C) Calorimeter analysis
This data are then representative of the vapor pressure of the reacting liquid—important data required for relief sizing
D) Pressure data
This type of data are most useful for designing relief systems to prevent high pressures due to runaway reactors.
C) Calorimeter analysis
In this type of reaction system heat of vaporization of the liquid cools, or tempers, the reaction mass during the relief discharge. This is also called a vapor system.
A) Volatile/tempered reaction
