d. What is the empirical formula for octane?

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Identify the molecular formula of octane, which is C_8H_{18}.

Determine the greatest common divisor (GCD) of the subscripts in the molecular formula. For C_8H_{18}, the GCD is 2.

Divide each subscript in the molecular formula by the GCD to simplify the ratio. For C_8H_{18}, divide 8 and 18 by 2.

Write the simplified formula using the new subscripts obtained from the division. This gives the empirical formula.

The empirical formula represents the simplest whole-number ratio of atoms in the compound.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Empirical Formula

The empirical formula of a compound represents the simplest whole-number ratio of the elements present in that compound. It does not provide information about the actual number of atoms in a molecule but rather the relative proportions of each element. For example, the empirical formula for glucose (C6H12O6) is CH2O, indicating a 1:2:1 ratio of carbon, hydrogen, and oxygen.

Molecular Formula

The molecular formula of a compound indicates the actual number of atoms of each element in a molecule. It can be derived from the empirical formula by multiplying the subscripts by a whole number. For octane, the molecular formula is C8H18, which shows that there are 8 carbon atoms and 18 hydrogen atoms in each molecule, while the empirical formula would reflect the simplest ratio of these elements.

Octane Structure

Octane is a hydrocarbon with the chemical formula C8H18, belonging to the alkane family. It consists of a straight-chain structure or branched isomers, where carbon atoms are connected by single bonds. Understanding octane's structure is essential for determining its empirical formula, as it helps in identifying the ratio of carbon to hydrogen atoms in the compound.

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