9. The chemical composition of olivine is (Mg, Fe SiO4. Which one of the followi

Question

9. The chemical composition of olivine is (Mg, Fe SiO4. Which one of the following correctly de- scribes the chemical composition or crystal structure of olivine? (A) Silicon (Si) and oxygen (O) have a similar size and charge and thus substitute for one another in the crystal structure of olivine. (B) Mag nesium (Mg) and iron (Fe) are the most abundant elements in the earth's crust. (C) Magnesium and iron cations help balance the negative charge of the silicon-oxygen tetrahedrons. (D) Both answers A and B (but not C) correctly describe olivine INSTRUCTION: Refer to the pressure-temperature dia- gram (right) describing magma, or solid igneous rock. The diagonal line represents the boundary between solid and melt phases (solid material on one side of the line, and melted on the other side) low Temperature high low 1V 10. Which one of the following statements is correct? (A) Following the arrow from i to ii (i.e., reducing the pressure) will result in melting. (B) Following the arrow from iii toA iv (increasing the temperature, will result in crystalliza- tion. (C) Following the arrow from i to ii will result in crystallization. (D) Addition of water will shift the bound- high ary between the solid and the melt phases to a higher tem perature (toward vi) Vi

Explanation / Answer

9.Answer: (C)Magnesium and Iron cations help balance the negative charge of the silicon - oxygen tetrahedrons. Explanation:Silicon tetrahedron has negative charge i.e., extra electrons which they provide to magnesium and iron to form a crystal structure. 10.Answer: (D ). Addition of water will shift the boundary between the solid and melt phases to a higher temperature(toward vi) Explanation: Addition of water will leads to use of more temperature to reach the melting point of rock thus the boundary layer gets shifted.

Related Questions

Navigate

• Browse (All)
• Browse 9
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.