Ethanol (C2H5OH) melts a - 144 oC and boils at 78 °C. The enthalpy of fusion of ethanol is 5.02 kj/mol, and its enthalpy of vaporization is 38.56 kj/mol. The specific heats of solid and liquid ethanol are 0.97j/g - k and 2.3 j/g - K, respectively.

(a) How much heat is required to convert 42.0 g of ethanol at 35 °C to the vapor phase at 78 °C?

(b) How much heat is required to convert the same amount of ethanol at - 155 oC to the vapor phase at 78 °C?

For a: The total heat required is 36621.5 J

For b: The total heat required is 58944.5 J

Explanation:

To calculate the heat required at different temperature, we use the equation:

        .........(1)

where,

q = heat absorbed

m = mass of substance

= specific heat capacity of substance

= change in temperature

To calculate the amount of heat required at same temperature, we use the equation:

     ........(2)

where,

q = heat absorbed

m = mass of substance

= enthalpy of the reaction

The processes involved in the given problem are:

We are given:

Change in temperature remains the same.

Putting values in equation 1, we get:

We are given:

Conversion factor: 1 kJ = 1000 J

Molar mass of ethanol = 46 g/mol

Putting values in equation 2, we get:

Total heat required =

Total heat required =

Hence, the total heat required is 36621.5 J

The processes involved in the given problem are:  

We are given:

Change in temperature remains the same.

Putting values in equation 1, we get:

We are given:

Putting values in equation 2, we get:

We are given:

Change in temperature remains the same.

Putting values in equation 1, we get:

We are given:

Putting values in equation 2, we get:

Total heat required =

Total heat required =

Hence, the total heat required is 58944.5 J

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

56 moles of   lieter in chemistry