- a. What name is given to a naturally occurring substance that has a definite composition?
b. If this substance is concentrated and is considered valuable, it is called a(n) ore .
- Iron is the most common element in the ``whole'' earth. Only about 6% of the crust is made up of iron. What does this tell us about the distribution of minerals on the earth?
Minerals are not evenly distributed - there is differentiation.
- What are the three ways that minerals are concentrated or formed on earth?
- Transfer by magma
- Hydrothermal processes
- Marble and limestone, common building materials, are composed of what mineral?
- What is the similarity about the destruction of buildings and statues and the formation of caves?
Both processes are caused by acid acting on calcium carbonate.
- What is the main chemical component of sand?
- What is the difference in silicates like asbestos, mica, and quartz?
The way silicon - oxygen tetrahedra are bonded to their neighbors (1, 2 or 3 dimensions) affects the properties of the silicate.
- What is the name of the process used to obtain pure elements like silicon?
- Why was pure silicon important for the ``information age''?
Pure silicon is needed for the computer chips and integrated circuits found in so many items.
- The density of silicate rocks varies between 2 and 3 g/mL. The density of iron is about 9 g/m:. How do these values relate to what we know about the structure of the earth?
The more dense iron in found in greater amounts near the core; the less dense silicates are found near the surface.