In part (a)(i), performance was fair however, some candidates took the advantages to mean just the properties.  In (a)(ii), candidates are expected to know that the glass of the bulb of the thermometer first expands and  that the linear expansivity of mercury is more than that of glass.  Most candidates failed to explain the observation correctly.  Performance was low.

In part (b), high performance was recorded.  However, few candidates wrote ‘area of liquid’   instead of ‘area of liquid exposed’.
In (c), this numerical part was correctly done by most candidates except in few cases where 
wrong units was quoted for the final answer.  Also in (d), performance was fair.

The expected answers are:

1. (i)   Advantages of alcohol over mercury as a thermometric liquid

                 -      lower freezing point
                 -      cheaper

                 -      easily expansively

• -     the glass of the bulb of the thermometer first expands; hence the mercury level 

      fails
-     the expansion of the mercury increases more than that of the glass
-     and the liquid rises

•     Factors other than temperature affecting the rate of evaporation of a liquid

                -     wind
                -     humidity/dryness of air
                -     nature of liquid/viscosity/density
                -     area of liquid exposed
                -     pressure.

• (i)   Q  = mC Dθ

                 =  100 x 120 x (320 – 40)
                 =  3360000 J

           (ii)   Q  =  ml
                   = 100 x 0.25 x 105
                   =  2500000 J

          (iii)   Pt  =  ml
                  10,000 t = 2500000
                   t  =  250s

•       Precautions

                -    calorimeter should be (well) lagged
                -    calorimeter should be shielded from heat source
                -     only dry steam should be used
                -     mixture should be gently and continually stirred.