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

Carbon has an atomic number of 6 and an atomic weight of 12.011. This means that…

6 protons and a varying number of neutrons

Solid materials that do not possess an orderly arrangement of atoms are called…

glasses (amorphous solids)

Each element has a unique number of…

protons

In the periodic table of the elements, as one goes from left to right along a row…

the atomic number increases and elements become less metallic; the number of electrons in the outer shell increases and electronegativity tends to increase

Which of the following elements commonly forms anions?

oxygen

Diamond is an example of what kind of bonding?

covalent

Chemical substances that have exactly the same chemical formula, but different crystal structures are called…

polymorphs

The chemical formula (Mg, Fe)2SiO4 describes which of the following minerals?

olivine

Most common rock-forming minerals are…

silicates

An antiproton is an atomic particle that has…

the same mass as a proton but a negative charge (charge of an electron)

A certain radioactive element has a half-life of 20d. The time it will take for 7/8 of the atoms originally present to disintegrate is… (1/8 left).

Each half life reduces the original quantity by half, so 60 d

The energy released by the nuclear bomb that destroyed Hiroshima was equivalent to 12.4 kilotons of TNT. This is equivalent to 9.0×10^26 MeV. The mass that was converted into energy in this explosion was… (MeV to J, E=mc²)

1.6×10^-3 kg

A moderator is used to slow… (nuclear reactor)

neutrons; this process increases the likelihood of further fission reactions

The cosmic microwave background radiation is…

the remnant radiation from the Big Bang, filling the universe and providing evidence for the Big Bang theory (radiation that was around when electrons and protons combined to form neutral hydrogen atoms)

According to Hubble’s law, the age of the universe…

10-15 billion years

What are the four known types of forces in nature in order of decreasing strength?

the strong nuclear force, the electromagnetic force, the weak nuclear force, and gravity

Particles that participate in the strong nuclear interaction are called…

hadrons, primarily protons and neutrons

Current thought is that all matter is composed of…

six quarks and six leptons

The fact that the binding energy per nucleon is roughly a constant over most of the range of stable nuclei is a consequence of the fact that the nuclear force is…

short-range

The total yearly world consumption of energy is approximately 4.0×10^20 J. How much mass would have to be completely converted into energy to provide this amount of energy?

1.3×10^4 kg

Rutherford’s experiments, in which he bombarded a very thin gold foil with alpha particles, showed that… 

most of the alpha particles passed through the foil with negligible deflection but some were deflected through large angles (this means that the nucleus is small and dense, leading to the conclusion that atoms have a concentrated center)

The interaction that describes the forces among nucleons that hold nuceli together is…

the strong nuclear (hadronic) interaction

The following fusion reaction occurs in the sun—> 32He +42He—>74Be with the nuclei masses being 3He=3.016049 u, 4He= 4.002604 u, 7Be=7.016930 u. The energy released or absorbed by the reaction is…

1.6 MeV, absorbed