Page 98 - Chemistry - XI
P. 98

Result

              The increasing order of acid present in tea samples is __________________.

                                                          PROJECT - 6


              Introduction
              The rate of evaporation depends upon boiling point of a liquid. Boiling point depends upon intermolecular
              forces of attraction. The lesser the intermolecular forces of attraction, lower will be the boiling point, more
              easily liquid will get vaporised. Highly volatile liquids are stored in airtight containers at low temperature.

              Objective

              To study the relationship between the rates of evaporation of diff erent liquids and their chemical constitution.

              Principle/Theory
              The rate of evaporation depends upon nature of liquid, i.e. its boiling point, surface area, wind speed,
              and  atmospheric  pressure.  Relate  the  diff erence  in  rates  of  evaporation  of  liquids  with  their  chemical
              constitution.


              Materials Required
              Five clean weighting tubes or bottles with stopper, 10 mL of ethanol, ether, carbon tetrachloride, acetone,
              chloroform, and digital balance

              Procedure

              1.  Take fi ve clean dry weighing bottles and mark them as A, B, C, D, and E.
              2.  Weigh each weighing tube with its stopper.
              3.  Pour 10 mL of ethanol in A, ether in B, carbon tetrachloride in C, acetone in D and chloroform in E in
                  each weighing bottle.
              4.  Weigh each weighing bottle again and fi nd the mass of liquid taken in a weighing bottle.

              5.  Remove all the stoppers of the weighing bottles and keep them at room temperature for one hour.
              6.  After exactly one hour, close the mouth of all the weighing bottles with their stoppers and weigh them
                  again one by one.
              7.  Calculate the loss of mass of each liquid and rate of evaporation of each liquid in grams of liquid

                  evaporated per second.

              Observations
               Sample Mass of             Mass of weighing  Mass of      Mass of           Loss of      Rate of
                         weighing         bottle with 10 mL liquid       weighing bottle  mass of       evaporation/
                         bottle           of liquid                      after 1 hour      liquid       sec
                  A

                  B
                  C
                  D D
                   E E

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