Question

Dimethyl ether, CH₃OCH₃(g)CH₃OCH₃(g), is an industrially useful organic compound that is a gas at room temperature. Consider the following balanced thermochemical equations:

CH₃OCH₃(g)+3O₂(g)→2CO₂(g)+3H₂O(g). ΔH∘=−1328kJ

Answer 1

In high school chemistry, the boiling points for ethyl methyl ether, 2-methylpropane, and acetone are compared based on their molecular structures and intermolecular forces, leading to the general order of increasing boiling points from isobutane to ether to acetone.

Step-by-step explanation:

Understanding the properties of various organic compounds is a key aspect of high school chemistry. When comparing the boiling points of different compounds such as ethyl methyl ether (CH3OCH2CH3), 2-methylpropane (isobutane, (CH3)2CHCH3), and acetone (CH3COCH3), it's important to consider their molecular structure and intermolecular forces. Ethers like ethyl methyl ether generally have lower boiling points than ketones like acetone due to the weaker van der Waals forces in ethers compared to the dipole-dipole interactions and possible hydrogen bonding in ketones.

Molecules are arranged in order of increasing boiling points based on the strength of their intermolecular forces, with more polar molecules and those capable of hydrogen bonding tending to have a higher boiling point. Therefore, acetone with its polar carbonyl group and the possibility of some hydrogen bonding, tends to have a higher boiling point than an ether, which lacks these interactions. However, the branching in isobutane reduces the surface area for van der Waals forces, thus it would have a lower boiling point than a straight-chain ether with similar molar mass. Consequently, the order of increasing boiling points is typically 2-methylpropane, ethyl methyl ether, and then acetone.