Practice Pakistan questions with answers and explanations.
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O is the chemical symbol for oxygen.
Element symbols use one or two letters.
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pH values below 7 indicate acidity.
A pH of 3 is distinctly acidic.
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Iron's symbol Fe comes from the Latin word ferrum.
It is a common structural metal.
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pH values above 7 indicate basicity.
A pH of 10 is alkaline.
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Sodium's symbol Na comes from the Latin natrium.
It is a highly reactive alkali metal.
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Each water molecule has two hydrogen atoms and one oxygen atom.
Its formula is H₂O.
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Carbon dioxide contains one carbon atom and two oxygen atoms.
Its formula is CO₂.
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An element contains atoms with the same number of protons.
It cannot be broken into simpler substances by ordinary chemical means.
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Common table salt is sodium chloride.
It consists of sodium and chloride ions.
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A compound contains different elements chemically bonded together.
Its properties differ from those of its constituent elements.
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Most common combustion reactions require oxygen.
Removing oxygen can extinguish a fire.
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Mixture components retain many of their own properties.
They can often be separated by physical methods.
