chemistry : class12 Oxygenated Minerals : Occurrence of Group 16 elements : p-Block Elements MCQ Questions and Answers
Practice important
Oxygenated Minerals
MCQ questions and answers.
Page 1
of
1
|
10
MCQ Questions
1. Which set contains only oxygenated minerals or mineral constituents that represent distinct chemical classes of oxygen-containing compounds of oxygen in the Earth's crust?
A.
SiO2, CaCO3, CaSO4·2H2O, and aluminosilicates
B.
SiCl4, CaCO3, CaSO4·2H2O, and aluminosilicates
C.
SiO2, CaS, CaSO4·2H2O, and aluminosilicates
D.
SiO2, CaCO3, CaCl2, and aluminosilicates
Correct Answer:
SiO2, CaCO3, CaSO4·2H2O, and aluminosilicates
Explanation:
Silica, carbonates, hydrated sulphates, and silicates are oxygen-containing mineral constituents. The other sets include chloride or sulphide compounds, which do not represent oxygenated minerals in the stated sense.
2. Which pairing correctly matches an oxygenated mineral with its principal anion or structural unit?
Explanation:
Calcite is CaCO3 and contains carbonate ions, gypsum is CaSO4·2H2O and contains sulphate ions, while quartz is SiO2 with an extended Si–O framework.
3. A mineral sample contains 46.6% oxygen by mass and consists predominantly of SiO2. Which conclusion about oxygen occurrence is most appropriate?
A.
Oxygen is present only as a free element in the sample
B.
Oxygen is a major constituent of the Earth's crust through oxygenated minerals such as silica and silicates
C.
Oxygen occurs in the crust mainly as elemental O2 trapped in quartz
D.
Oxygenated minerals are restricted to sulphates and exclude silicates
Correct Answer:
Oxygen is a major constituent of the Earth's crust through oxygenated minerals such as silica and silicates
Explanation:
Oxygen constitutes about 46.6% by mass of the Earth's crust, largely because it is chemically combined in oxides, silicates, carbonates, and sulphates rather than occurring there mainly as free O2.
4. Which formula represents a hydrated oxygenated mineral in which oxygen is supplied both by a sulphate group and by water of crystallisation?
A.
CaSO4·2H2O
B.
CaCO3
C.
SiO2
D.
Al2O3
Correct Answer:
CaSO4·2H2O
Explanation:
Gypsum, CaSO4·2H2O, contains oxygen in the sulphate ion and additionally in two molecules of crystallisation water. The other formulas do not contain water of crystallisation.
5. For equal masses of pure CaCO3 and CaSO4·2H2O, which sample contains the greater mass percentage of oxygen?
A.
CaCO3, because carbonate contains three oxygen atoms and has a lower formula mass
B.
CaSO4·2H2O, because it contains sulphate oxygen as well as water oxygen
C.
Both contain exactly the same mass percentage of oxygen
D.
The comparison is impossible because neither is an oxygenated mineral
Correct Answer:
CaSO4·2H2O, because it contains sulphate oxygen as well as water oxygen
Explanation:
CaCO3 contains 48/100, approximately 48%, oxygen by mass. CaSO4·2H2O contains 96/172, approximately 55.8%, oxygen by mass, because oxygen occurs in both the sulphate ion and the waters of crystallisation.
6. Which sequence correctly orders the oxygen-containing mineral constituents from the simplest oxide framework to a more compositionally complex hydrated sulphate?
A.
SiO2, CaCO3, CaSO4·2H2O
B.
CaSO4·2H2O, CaCO3, SiO2
C.
CaCO3, SiO2, CaSO4·2H2O
D.
SiO2, CaSO4·2H2O, CaCO3
Correct Answer:
SiO2, CaCO3, CaSO4·2H2O
Explanation:
SiO2 is a simple oxide, CaCO3 is an oxygenated carbonate, and CaSO4·2H2O is a hydrated oxygenated sulphate. The sequence reflects increasing complexity of the oxygen-containing composition.
7. A mineral analysis reports calcium, sulphur, oxygen, and hydrogen, with hydrogen present in a fixed ratio corresponding to water of crystallisation. Which commonly occurring oxygenated mineral is indicated?
A.
Gypsum, CaSO4·2H2O
B.
Calcite, CaCO3
C.
Quartz, SiO2
D.
Hematite, Fe2O3
Correct Answer:
Gypsum, CaSO4·2H2O
Explanation:
Gypsum contains calcium, sulphur, oxygen, and hydrogen because its formula is CaSO4·2H2O. The hydrogen belongs to the crystallisation water; the other minerals listed contain no hydrogen.
8. Which statement best explains why silicate minerals are especially important examples of oxygenated minerals in the Earth's crust?
A.
They contain silicon–oxygen units that combine with metal cations to form extensive mineral structures
B.
They contain only free O2 molecules held between silicon atoms
C.
They are formed exclusively from carbonate ions and alkaline-earth metals
D.
They contain sulphur–oxygen units but no silicon–oxygen bonding
Correct Answer:
They contain silicon–oxygen units that combine with metal cations to form extensive mineral structures
Explanation:
Silicate minerals are built from Si–O units, commonly linked into chains, sheets, or three-dimensional frameworks and balanced by metal cations. This accounts for their abundance among oxygenated crustal minerals.
9. Which option correctly identifies the oxygen-containing mineral class represented by each formula: Al2O3, CaCO3, and CaSO4·2H2O, respectively?
Explanation:
Al2O3 is an oxide, CaCO3 is a carbonate, and CaSO4·2H2O is a hydrated sulphate. Each class is an important form in which oxygen occurs in mineral matter.
10. A crustal sample contains quartz, calcite, and gypsum. Which combination of oxygen-containing groups must be present in the sample?
A.
Silicon–oxygen framework, carbonate groups, and sulphate groups with crystallisation water
B.
Silicon–sulphur framework, nitrate groups, and oxide ions only
C.
Carbonate groups, sulphide groups, and chloride ions with crystallisation water
D.
Silicon–oxygen framework, sulphide groups, and elemental oxygen molecules
Correct Answer:
Silicon–oxygen framework, carbonate groups, and sulphate groups with crystallisation water
Explanation:
Quartz is SiO2 with a silicon–oxygen framework, calcite is CaCO3 with carbonate groups, and gypsum is CaSO4·2H2O with sulphate groups and crystallisation water.
Short Questions and Answers
Practice short questions and answers related to
Oxygenated Minerals
.
Short questions are currently unavailable for this page.