Download Reading Science: The Carbon-Hydrogen Connection in Outer Space

7.6A: Organic Compounds
Matter and Energy
The Carbon-Hydrogen Connection in Outer Space
(Lexile 900L)
1 People have known for hundreds of years that carbon
is an element. It has also been known that carbon can
combine with hydrogen, oxygen, phosphorus, nitrogen,
and sulfur to form organic compounds. What had not
been known, however, is that hydrocarbons can be
found on other celestial bodies. They have even found
them on one of Saturn’s moons, Hyperion.
2 In 2007, NASA’s Cassini spacecraft completed a survey of Hyperion. It found that the Saturn
satellite has cup-like craters filled with hydrocarbons. These are the simplest forms of organic
compound, containing only carbon and hydrogen. Scientists believe this discovery shows that
the basic chemicals for carbon-based life are widespread in our solar system. Hyperion does
not just have hydrocarbons. It contains water and carbon dioxide (carbon-oxygen compound)
as well.
3 Our own Earth is full of hydrocarbons. For about 200 years, scientists have divided chemical
compounds into two categories: organic and inorganic. Hydrocarbons have historically been
considered “organic,” or “living” matter. That definition is not valid any more. Compounds can
now be produced in a scientific laboratory and so may never have been associated with a living
organism. There are a few compounds that can be classified either way!
4 In organic chemistry, the three most important elements are carbon, hydrogen, and oxygen.
Other elements such as nitrogen, sulfur, or phosphorus can also be found in organic
compounds. Each of these elements makes different kinds of connections. They can come
together to form millions of compounds. All play a role in the formation and continuation of life
on this planet.
5 It is exciting to think that those compounds might be found on other planets or moons. Using
scientific probes and experiments, scientists will continue to look for clues about the origin of
these compounds. They will also continue to survey our solar system to see how widespread
they are.
1
7.6A: Organic Compounds
Matter and Energy
1
Complete the following analogy:
hydrocarbons:carbon as carbon dioxide:_____
2
3
A
phosphorous
B
sulfur
C
hydrogen
D
oxygen
What could the reader infer from the reading about hydrocarbons?
A
Life started on other planets before it started on Earth.
B
All planets and satellites in the solar system contain hydrocarbons.
C
The building blocks of carbon-based life are found on planets or
satellites other than Earth.
D
No bodies in our solar system except Earth contain hydrocarbons.
What other elements besides carbon are commonly found in organic
compounds?
A
hydrogen and oxygen
B
helium and phosphorus
C
nitrogen and argon
D
oxygen and lead
2
7.6A: Organic Compounds
Matter and Energy
4
5
Which of NASA’s spacecraft identified the hydrocarbons on Saturn’s moon?
A
Cassini
B
Voyager II
C
Hubble
D
Mariner
Which of these compounds is a hydrocarbon?
A
carbon dioxide (made of carbon and oxygen)
B
calcium carbonate (made of calcium, carbon, and oxygen)
C
ethanol (made of carbon, hydrogen, and oxygen)
D
octane (made of carbon and hydrogen)
3