:a certain liquid has a vapor pressure of 6.91 mmhg at 0 °c. if this liquid has a normal boiling point of 105 °c, what is the liquid's heat of vaporization in kj/mol?

liquid's heat of vaporization = 38.4 kJ/mol

Explanation:

given data

vapor pressure P1 = 6.91 mmHg

at temperature = 0 °C = 273.15 K

boiling temperature = 105 °C

solution

for vapor pressure and temperature we get here

P2 = 760.0 mmHg

T2 = 68.73°C = 378.15 K

we use here the Clausius-Clapeyron Equation that is

ln =     .................1

put here value

In

solve it we get

x = 38445 J/mol

liquid's heat of vaporization = 38.4 kJ/mol

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.