About 99% by mass of Earth's atmosphere is composed of the two elements
A) nitrogen and oxygen.
B) oxygen and carbon dioxide.
C) oxygen and silicon.
D) hydrogen and helium.
Correct Answer:
Verified
Q50: The periodic table is most easily understood
Q51: Diamond and graphite are
A) similar in physical
Q52: Pencil "lead" (graphite) is made primarily of
A)
Q53: When the atoms of two or more
Q54: Two or more forms of the same
Q56: About 74% by mass of Earth's crust
Q57: Nearly 100% by mass of Earth's core
Q58: About 15% by mass of Earth's core
Q59: "Buckyball" is an allotrope of the element
A)
Q60: Only two elements, mercury and _, are
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