Heptane (c7h16) and octane (c8h18) are constitutents of gasoline. at 80 degree celsius, the vapor pressure of heptane is 428mmhg and the vapor pressure of octane is 175mmhg. what xheptane in a mixture of heptane and octane that has a vapor pressure of 305mmhg and 80 degree celsius?

The mole fraction of heptane at 80°C is 0.506

Explanation:

We are given:

Vapor pressure of heptane at 80°C = 428 mmHg

Vapor pressure of octane at 80°C = 175 mmHg

Total pressure at 80°C = (428 + 175) = 603 mmHg

To calculate the mole fraction of heptane at 80°C, we use the equation given by Raoult's law, which is:

where,

= partial pressure of heptane = 305 mmHg

= total pressure  = 603 mmHg

= mole fraction of heptane = ?

Putting values in above equation, we get:

Hence, the mole fraction of heptane at 80°C is 0.506

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.

answer seismograph;