1. In its elemental form, hydrogen normally exists as which molecule?
A.
H
B.
H2
C.
H3
D.
H4
Correct Answer:
H2
Explanation:
Hydrogen is diatomic in its elemental form, meaning each molecule contains two hydrogen atoms and is represented as H2.
2. How many hydrogen atoms are present in one molecule of hydrogen gas?
A.
One
B.
Two
C.
Three
D.
Four
Correct Answer:
Two
Explanation:
A hydrogen molecule is H2, so it contains two hydrogen atoms.
3. The term 'diatomic' means that a molecule contains:
A.
One atom
B.
Two atoms
C.
Three atoms
D.
Four atoms
Correct Answer:
Two atoms
Explanation:
The prefix 'di-' means two; therefore, a diatomic molecule contains two atoms.
4. Which of the following correctly represents one molecule of hydrogen gas?
A.
H
B.
2H
C.
H2
D.
H2O
Correct Answer:
H2
Explanation:
H2 is the molecular formula of hydrogen gas and shows that two hydrogen atoms form one molecule.
5. Hydrogen gas is called diatomic because its molecules contain:
A.
Two hydrogen atoms
B.
Two oxygen atoms
C.
One hydrogen atom
D.
One hydrogen and one oxygen atom
Correct Answer:
Two hydrogen atoms
Explanation:
Hydrogen gas consists of H2 molecules, each made of two hydrogen atoms.
6. What is the atomic ratio of hydrogen atoms in a hydrogen molecule?
A.
1:1
B.
1:2
C.
2:1
D.
2:2
Correct Answer:
1:1
Explanation:
A hydrogen molecule contains two identical hydrogen atoms, so the simplest atomic ratio is 1:1.
7. Which statement about hydrogen gas is correct?
A.
It consists mainly of single hydrogen atoms under ordinary conditions.
B.
It consists of molecules containing two hydrogen atoms.
C.
It consists of molecules containing three hydrogen atoms.
D.
It consists of hydrogen and oxygen atoms in equal numbers.
Correct Answer:
It consists of molecules containing two hydrogen atoms.
Explanation:
Under ordinary conditions, elemental hydrogen exists mainly as diatomic H2 molecules.
8. If one H2 molecule is separated into its atoms, how many hydrogen atoms are formed?
A.
One
B.
Two
C.
Three
D.
Four
Correct Answer:
Two
Explanation:
The formula H2 indicates that one hydrogen molecule contains two hydrogen atoms.
9. Which formula represents two separate hydrogen atoms rather than one hydrogen molecule?
A.
H2
B.
2H
C.
H3
D.
H2O
Correct Answer:
2H
Explanation:
2H represents two separate hydrogen atoms, whereas H2 represents one diatomic hydrogen molecule.
10. The molecule H2 contains how many hydrogen-hydrogen atom connections?
A.
None
B.
One
C.
Two
D.
Three
Correct Answer:
One
Explanation:
The two hydrogen atoms in an H2 molecule are joined by one hydrogen-hydrogen bond.
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