Explain why the ethanol has a boiling point of 78.4degrees Celsius while dimethylether has a boiling point of -24degrees Celsius and they have the same mass molecular substances
Ethanol is polar and has hydrogen bonds.
Ethanol and dimethylether have different boiling points due to differences in their molecular structure and intermolecular forces. To understand this, we need to consider the concept of intermolecular forces and how they affect boiling points.
Boiling point is the temperature at which a liquid changes into a gas at atmospheric pressure. It primarily depends on the strength of the intermolecular forces between molecules. Stronger intermolecular forces require more energy to overcome and therefore result in higher boiling points.
In the case of ethanol, it contains hydrogen bonding, which is a strong intermolecular force. Ethanol molecules have a polar O-H bond, and these polar groups can form hydrogen bonds with neighboring ethanol molecules. Hydrogen bonding is stronger than the intermolecular forces in dimethylether.
On the other hand, dimethylether does not have a polar O-H bond and lacks the ability to form hydrogen bonds like ethanol. Instead, dimethylether exhibits weaker intermolecular forces such as London dispersion forces or van der Waals forces. These forces are relatively weaker and require less energy to overcome, resulting in a lower boiling point for dimethylether.
To further explain why ethanol has a boiling point of 78.4 degrees Celsius, we can compare it to other similar molecular substances. Methanol (CH3OH) has a boiling point of 64.7 degrees Celsius, slightly lower than ethanol, due to the presence of H-bonding. However, ethane (C2H6), which has no polar groups or hydrogen bonding, has a significantly lower boiling point of -88.6 degrees Celsius.
In summary, the difference in boiling points between ethanol and dimethylether can be attributed to the presence of hydrogen bonding in ethanol, which leads to stronger intermolecular forces. Understanding the molecular structure and intermolecular forces allows us to predict the relative boiling points of different substances.