Essential Questions
1. How do the different forms of phosphorus vary in structure and properties?
2. What is the process for producing violet phosphorus?
3. What are the unique properties of black phosphorus?
4. How is scarlet phosphorus obtained and what makes it distinct?
5. What factors contribute to the chemiluminescence of white phosphorus?
Learning Objectives
1. Identify the different forms of phosphorus mentioned in the text
2. Understand the properties and uses of white, red, violet, and black phosphorus 3. Explain the process of autoxidation and thermal decomposition of phosphorus 4. Recognize the conditions under which different forms of phosphorus are produced 5. Understand the concept of chemiluminescence and its relation to phosphorus Questions
1. What is the form of phosphorus that is a napalm additive?
A. White phosphorus B. Red phosphorus C. Violet phosphorus D. Black phosphorus
○ Correct answer: A. White phosphorus 2. Which form of phosphorus is a napalm additive?
A. White phosphorus B. Violet phosphorus C. Black phosphorus D. Red phosphorus
○ Correct answer: A. White phosphorus
3. What is the form of phosphorus that is insoluble in water but soluble in carbon disulfide?
A. Black phosphorus B. White phosphorus C. Red phosphorus D. Violet phosphorus
○ Correct answer: B. White phosphorus
4. What does the thermal decomposition of P4 at 1100 K give?
A. White phosphorus B. Diphosphorus, P2 C. Red phosphorus D. Violet phosphorus
○ Correct answer: B. Diphosphorus, P2 5. Which form of phosphorus is polymeric in structure?
A. Black phosphorus B. White phosphorus C. Red phosphorus D. Violet phosphorus
○ Correct answer: C. Red phosphorus 6. How is red phosphorus formed?
A. By recrystallizing from molten lead
B. By day-long annealing of red phosphorus above 550 °C C. By heating white phosphorus to 250 °C
D. By exposing white phosphorus to sunlight
○ Correct answer: C. By heating white phosphorus to 250 °C 7. How is violet phosphorus produced?
A. By recrystallizing from molten lead
B. By day-long annealing of red phosphorus above 550 °C
C. By allowing a solution of white phosphorus in carbon disulfide to evaporate in sunlight D. By heating white phosphorus under high pressures
○ Correct answer: B. By day-long annealing of red phosphorus above 550 °C 8. At what temperature is black phosphorus the thermodynamically stable form?
A. At room temperature B. Above 550 °C C. Below 550 °C D. Above 1100 K
○ Correct answer: C. Below 550 °C 9. How is scarlet phosphorus obtained?
A. By heating white phosphorus under high pressures
B. By allowing a solution of white phosphorus in carbon disulfide to evaporate in sunlight C. By recrystallizing from molten lead
D. By day-long annealing of red phosphorus above 550 °C
○ Correct answer: B. By allowing a solution of white phosphorus in carbon disulfide to evaporate in sunlight 10. What were phosphors and phosphorescence used to describe?
A. Substances that shine in the dark without burning B. Highly reactive chemicals
C. Invisible gases D. Explosive materials
○ Correct answer: A. Substances that shine in the dark without burning
