Why is the boiling temperature of C2H5OH 78C and water is 100C at 760 Torr.

Because the vapor pressure of C2H5OH is 760 mm at 78 degrees C. And because the vapor pressure of H2O is 760 mm at 100 degrees C. The definition of boiling point is that temperature at which the vapor pressure of the liquid equals atmospheric pressure.

140.500 micrometers converted to pounds

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H2O has hydrogen bonding whereas C2H5OH has weak Van Der Waals forces. The stronger the bond holding the molecules of a substance together, the higher the boiling point of the substance. Hydrogen bond is stronger than van der waal's forces.

The boiling temperature of a substance is determined by the balance between the intermolecular forces of attraction and the pressure exerted on the substance. In the case of C2H5OH (ethyl alcohol) and water (H2O), their boiling temperatures differ due to differences in their molecular structures and intermolecular forces.

The boiling temperature of a substance depends on the strength of the intermolecular forces present. Ethyl alcohol (C2H5OH) has weaker intermolecular forces compared to water (H2O). Ethyl alcohol molecules have a smaller dipole moment compared to water molecules, resulting in weaker hydrogen bonding forces between ethyl alcohol molecules. Consequently, less energy is required to break these intermolecular forces, resulting in a lower boiling temperature for ethyl alcohol.

Water, on the other hand, has strong hydrogen bonding due to the highly polar nature of the water molecule. These hydrogen bonds between water molecules require more energy to break, resulting in a higher boiling temperature compared to ethyl alcohol.

Pressure also plays a role in determining the boiling temperature of a substance. The boiling temperature of both ethyl alcohol and water (at 1 atmosphere pressure) is commonly referred to as their normal boiling points. However, your question specifically mentions the boiling temperatures at 760 Torr.

Increasing the pressure on a substance increases its boiling temperature. Water boils at higher temperatures than ethyl alcohol at the same pressure because water molecules have stronger intermolecular forces. At 760 Torr pressure, the boiling point of water is 100°C, while ethyl alcohol boils at 78°C under the same pressure.

To determine the boiling temperature of substances at different pressures, you can refer to a vapor pressure chart or utilize a vapor pressure equation specific to the substance you're interested in. These references will provide the relationship between pressure and boiling temperature for different substances.