Tutorial 1
Mole and Atomic Concept
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1.
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Hydrocarbons
are organic compounds composed entirely of hydrogen and carbon. A 0.1647 g
sample of a pure hydrocarbon was burned in a C-H combustion train to produce
0.4931 g of CO2 and 0.269 g of H2O. Determine the masses
of C and H in the sample and the percentage of these elements in this
hydrocarbon.
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2.
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Compounds
containing sulphur and oxygen are serious air pollutants; they represent the
major cause of acid rain. Analysis of a sample of a pure compound reveals
that it contains 50.1 % sulphur and 49.9 % oxygen by mass. Determine the
simplest formula of the compound?
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3.
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A 20.882 g sample of an
ionic compound is found to contain 6.072 g of Na, 8.474 g of S and 6.33 g of
O. determine the simplest formula of the compound?
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4.
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A
0.1014 g sample of purified glucose was burned in a C-H combustion train to
produce 0.1486 g of CO2 and 0.0609 g of H2O. An
elemental analysis showed that the glucose contains only carbon, hydrogen and
oxygen.
i) Determine the masses of C, H and O in
the sample.
ii)
Other experiments show that its
molecular weight is approximately 180 amu. Determine the simplest formula of
glucose.
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5.
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Calcium carbonate (CaCO3)
are called calcite, is the
principal mineral found in limestone, marble, chalks, pearls, and the shells
of marine animals such as clams.
i) Calculate
the molar mass of calcium carbonate.
ii) A
certain sample of calcium carbonate contains 4.86 moles. What is the mass in
g of these samples?
iii) What is the mass of the CO32-
ions present?
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