Multiple Choice Exam 1

Approximately how long ago was the Big Bang?

10-15 billion years ago

Under intense pressure and high temperature, hydrogen atoms combine to form helium. This process is called…

nuclear fusion

What are the two most abundant elements in nebula (gas clouds) in the universe?

Hydrogen and helium

The process by which an originally homogenous Earth developed a dense core and a light crust is called…

differentiation

The heat that caused melting in the earth’s early history was supplied from which of the following events or causes?

a large impact event and radioactivity

How thick is the crust of the Earth?

about 40 km

The layer that separates the crust from the core is the…

mantle

What drives the earth’s internal heat engine?

radioactivity

In general, igneous rocks:

form by crystallization of solids from a liquid; they are typically formed from magma or lava

____ involves transfer of heat by the physical movement of the material.

Convection

____ is called the “father” of geology.

James Hutton

New seafloor is created at a ____

mid-ocean ridge

The descent of oceanic lithosphere into the mantle is the process of ____

subduction

Which of the following features is not associated with a convergent (transform) plate boundary?

a mid-ocean ridge (earthquakes, a deep-sea trench zone, volcanic activity is associated with the boundary)

The greatest threat to our environment is ____

volcanoes

The terms crust and lithosphere are synonymous

False

The crust of the Earth is static and stable.

False

The age of the Earth is though to be…

about 4.5 billion years old

Living organisms have been on Earth for ____ of earth’s history?

about 80%

Humans have been on Earth for ___ of earth’s history?

less than 1%

What caused dust and condensing material to accrete into planetesimals?

gravitational attraction and collisions

What planets are not one of the four inner planets?

Jupiter, Saturn, Uranus, Neptune

The outer planets are composed mostly of?

hydrogen and helium

The Earth’s external heat engine is not responsible for…

erosion

Oxygen built up in the Earth’s atmosphere because…

algae and other organisms employed photosynthesis

Which of the planets is not geologically active?

Mercury (and our moon; no significant internal heat or active geological processes)

When did geologists develop the theory of plate tectonics?

in the 1960s

The lithosphere is approximately ___ km thick

50-100 (the lithosphere is the rigid outer layer of the Earth that includes the crust and upper mantle)

Approximately how fast does an earth lithospheric plate move?

Several centimeters per year

Approximately how deep (below sea level) are deep-sea trenches?

10 km

What is the name of the large supercontinent that existed 200 million years ago when all of the continents were together?

Pangaea

The theory of plate tectonics was not initially widely accepted because ___

rocks of the Earth’s crust were considered too stiff for continents to move through them (static earth)

How many neutrons are in an atom of C?

6

How many electrons are in a neutral atom of C14?

6

Solids that do not possess an orderly 3D arrangement of atoms is called __

amorphous (non-crystalline solids)

An ion of C14 is formed by adding enough electrons to the L shell to completely fill it up. How many electrons are added?

4 because the L shell can hold a maximum of 8 electrons, and C14 has 4 electrons in its L shell

The ion Mg (II) has a charge of…

+2, indicating it has lost two electrons

Mg (II) is a(n) ….

cation

For the element 21^ZZ44, how many neutrons are present in the nucleus of the atom?

23 neutrons

What is the most common structural element of the silicate mineral group?

a silicon-oxygen tetrahedron (this structure consists of a silicon atom surrounded by four oxygen atoms in a tetrahedral arrangement)

The atomic mass number of an element is the …

total number of protons and neutrons in its nucleus

____ is the most abundant cation in the continental crust.

silicon (Si4+; the most common cation found in silicate minerals and ~28%)

____ is a common nesosilicate (island silicate) single tetrahedron

olivine (an abundant, green, magnesium-iron silicate mineral found in mafic and ultramafic rocks, the Earth's upper mantle, and some meteorites)

____ refers to two or more crystalline phases with the same composition but different structures.

Polymorphism

two atoms with teh same atomic number but different atomic masses

isotopes

____ describes two solid phases (minerals) which can mix in all proportions.

Solid solution

Which of the following statements about graphite and diamond is false?

graphite and diamond have the same density