If the container is closed and the ethanol is allowed to reach equilibrium with its vapor, how many grams of liquid ethanol remain? express your answer to two significant figures and include the appropriate units.

Explanation:

Let us assume that the given data is as follows.

        V = 3.10 L,        T = = (19 + 273)K = 292 K

       P = 40 torr    (1 atm = 760 torr)

So,     P =

             = 0.053 atm

          n = ?

According to the ideal gas equation, PV = nRT.

Putting the given values into the above equation to calculate the value of n as follows.

                 PV = nRT

                 0.1643 =

                    n =

It is known that molar mass of ethanol is 46 g/mol. Hence, calculate its mass as follows.

               No. of moles =

                    mass = g

                              = 0.315 g

Thus, we can conclude that the mass of liquid ethanol is 0.315 g.

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

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e