Using the general molecular formula for alkanes:
a. Predict the molecular formula of the C₂₈ straight-chain alkane.

Verified step by step guidance

1. Understand that alkanes are saturated hydrocarbons with the general molecular formula C_nH_2n+2, where n is the number of carbon atoms.
2. Identify the number of carbon atoms in the given alkane, which is 28 in this case.
3. Substitute n = 28 into the general formula for alkanes: C_nH_2n+2.
4. Calculate the number of hydrogen atoms by using the formula 2n + 2. Substitute n = 28 into this expression to find the number of hydrogen atoms.
5. Combine the number of carbon and hydrogen atoms to write the molecular formula of the C₂₈ straight-chain alkane.

Key Concepts

Alkanes

Alkanes are saturated hydrocarbons consisting entirely of single bonds between carbon atoms and hydrogen atoms. They follow the general molecular formula CnH2n+2, where n is the number of carbon atoms. This formula helps predict the number of hydrogen atoms in a straight-chain alkane.

Straight-Chain Alkanes

Straight-chain alkanes are a type of alkane where carbon atoms are connected in a linear sequence without any branching. This structure affects the molecular formula, as each carbon atom contributes to the overall count of hydrogen atoms according to the alkane formula CnH2n+2.

Molecular Formula Prediction

Predicting the molecular formula involves applying the general formula for alkanes, CnH2n+2, to determine the number of hydrogen atoms in a molecule. For a C28 straight-chain alkane, substituting n=28 into the formula gives C28H58, indicating 28 carbon atoms and 58 hydrogen atoms.