Calculate the heat required for the following two processes, and compare the results. a. A 100.0 g sample of solid ethanol melts at its melting point. Hfus = 4.94 kJ/mol

b. A 100.0 g sample of liquid ethanol vaporizes at its boiling point. Hvap = 38.6 kJ/mol

A. 10.74 KJ

B. 83.92 KJ

Explanation:

A. Data obtained from the question include the following:

Mass (m) of ethanol = 100g

Heat of fusion, Hfus = 4.94 kJ/mol

Heat (Q) =..?

Next, we shall determine the number of mole in 100g of ethanol, C2H5OH. This is illustrated below:

Mass of C2H5OH = 100g

Molar mass of C2H5OH = (2x12)+ (5x1) + 16 + 1 = 46g/mol

Number of mole (n) of C2H5OH =..?

Mole = Mass /Molar Mass

Number of mole (n) of C2H5OH = 100/46 = 2.174 moles.

Now, we can obtain the heat required to melt the ethanol as follow:

Q = n x Hfus

Q = 2.174 mol x 4.94 kJ/mol

Q = 10.74KJ

Therefore, 10.74 KJ of heat is required to melt the ethanol.

B. Data obtained from the question include the following:

Mass of C2H5OH = 100g

Heat of vaporisation, Hvap = 38.6 kJ/mol

Heat (Q) =..?

As calculated above, the number of mole in 100g of ethanol, C2H5OH is 2.174 moles.

The heat required to vaporise the ethanol can be obtained as follow:

Q = n x Hvap

Q = 2.174 mol x 38.6 kJ/mol

Q = 83.92 KJ

Therefore, 83.92 KJ of heat is required to vaporise the ethanol.

C. From the above calculations, a higher amount of heat energy i.e 83.92 KJ is required to vaporise the ethanol and a lesser amount of heat energy i.e 10.74 KJ is needed to melt the ethanol.

pure water does not conduct electricity very well. however, when certain substances are dissolved in water, the solution does conduct electricity. you can make a simple device that shows how well a solution conducts electricity. this device uses a flashlight bulb to indicate how well the solution conducts electricity. the better the solution conducts electricity, the brighter the bulb will glow.

explanation: