The boiling point of ethanol is 78.4 °C, and the enthalpy change for the conversion of liquid to vapor is ΔHvap = 38.56 kJ/mol. What is the entropy change for vaporization, ΔSvap, in J/(K ⋅ mol)?

Explanation:

The given data is as follows.

    Enthalpy of vaporization, = 38.56 kJ/mol

    Temperature (T) =

                                = (78.4 + 273) K

                                = 351.4 K

Now, we will calculate the change in entropy using the formula as follows.

                       =

                       = 0.109 kJ/mol K

Thus, w ecan conclude that the entropy change for vaporization is 0.109 kJ/mol K.

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.

in chemistry, adhesion and cohesion are attractive forces that exist between molecules. they hold the molecules together from each other. they are different in that adhesive force exists between molecules of different substance while cohesive force happens between molecules of same substance.

adhesion between water and glass causes water molecules at the edge of water and glass interface to climb up the wall in a narrow glass tube. this is called capillary action. cohesion is what gives glass its shape and causes water to form a droplet.