Section 10.4- Phosphorus

Question 1

the tenth most abundant element in the earth’s crust

Answer 1

phosphorus

Question 2

sixth most abundant element in the human body

Answer 2

phosphorus

Question 3

the two most important allotropes of phosphorus

Answer 3

white phosphorus
red phosphorus

Question 4

allotrope of phosphorus that is a transparent, waxy, crystalline solid composed of discrete tetrahedral P4 molecules

highly toxic

Answer 4

white phosphorus

Question 5

a much more stable allotrope of phosphorus that appears to be polymeric, consisting of chains of phosphorus molecules that have been joined

at much higher temperatures

Answer 5

red phosphorus

Question 6

commercially, elemental phosphorus is contained from phosphate rock by

Answer 6

heating it to more than 1000 C with coke (carbon) and silica sand

Question 7

calcium silicate is known as

Answer 7

slag

Question 8

the major use of elemental phosphorus is in the

Answer 8

synthesis of phosphoric acid and other phosphorus compounds

Question 9

a colorless liquid with boiling point of 76 C (phosphorus)

Answer 9

phosphorus trichloride

Question 10

phosphorus __________ is a yellow solid that decomposes at its melting point of 167C

Answer 10

pentachloride

Question 11

is formed when P4 is heated with sulfur

Answer 11

phosphate trisulfide

Question 12

one of the most important industrial chemicals in the United States

Answer 12

phosphoric acid

Question 13

phosphates work as

Answer 13

emulsifiers
fertilizers (superphosphates)

Question 14

a group of natural and synthetic chemicals that are toxic to insects and are widely used to protect food crops from pests

Answer 14

organophosphates

Question 15

an extremely important phosphate which serves as the energy carrier of the cell

Answer 15

TP