3.3: Writing Chemical Formulas (Problems)
- Page ID
- 98693
PROBLEM \(\PageIndex{1}\)
Explain why the symbol for an atom of the element oxygen and the formula for a molecule of oxygen differ.
- Answer
-
The symbol for the element oxygen, O, represents both the element and one atom of oxygen. A molecule of oxygen, O2, contains two oxygen atoms; the subscript 2 in the formula must be used to distinguish the diatomic molecule from two single oxygen atoms.
PROBLEM \(\PageIndex{2}\)
Write the molecular and empirical formulas of the following compounds:
(a)
(b)
(c)
(d)
- Answer a
-
molecular: CO2
empirical: CO2
- Answer b
-
molecular: C2H2
empirical: CH
- Answer c
-
molecular: C2H4
empirical: CH2
- Answer d
-
molecular: H2SO4
empirical: H2SO4
PROBLEM \(\PageIndex{3}\)
Write the molecular and empirical formulas of the following compounds:
(a)
(b)
(c)
(d)
- Answer a
-
molecular: C4H8
empirical: CH2
- Answer b
-
molecular: C4H6
empirical: C2H3
- Answer c
-
molecular: H2Si2Cl4
empirical: HSiCl2
- Answer d
-
molecular: H3PO4
empirical: H3PO4
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-
PROBLEM \(\PageIndex{4}\)
Determine the empirical formulas for the following compounds:
(a) caffeine, C8H10N4O2
(b) fructose, C12H22O11
(c) hydrogen peroxide, H2O2
(d) glucose, C6H12O6
(e) ascorbic acid (vitamin C), C6H8O6
- Answer a
-
C4H5N2O
- Answer b
-
C12H22O11
- Answer c
-
HO
- Answer d
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CH2O
- Answer e
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C3H4O3
PROBLEM \(\PageIndex{5}\)
Determine the empirical formulas for the following compounds:
(a) acetic acid, C2H4O2
(b) citric acid, C6H8O7
(c) hydrazine, N2H4
(d) nicotine, C10H14N2
(e) butane, C4H10
- Answer a
-
CH2O
- Answer b
-
C6H8O7
- Answer c
-
NH2
- Answer d
-
C5H7N
- Answer e
-
C2H5
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-
Contributors
Paul Flowers (University of North Carolina - Pembroke), Klaus Theopold (University of Delaware) and Richard Langley (Stephen F. Austin State University) with contributing authors. Textbook content produced by OpenStax College is licensed under a Creative Commons Attribution License 4.0 license. Download for free at http://cnx.org/contents/85abf193-2bd...a7ac8df6@9.110).
- Adelaide Clark, Oregon Institute of Technology