Change of State
4 marks · EasyA student sets up a practical to investigate the specific heat capacity of a metal block.
List two measurements the student must take to calculate the specific heat capacity.
State and explain one reason why the calculated value of the specific heat capacity might be higher than the true value.
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(a) The student's must measure: (1) the mass of the metal block, and (2) the temperature change of the block OR the thermal energy supplied.
(b) Heat is lost to the surroundings (not all energy goes into the block). This makes the calculated specific heat capacity greater than the true value.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States mass of block measured.
B2 (a) · 1 mark · States temperature change or energy supplied measured.
B1 (b) · 1 mark · Mentions heat/energy lost to surroundings or similar error.
B2 (b) · 1 mark · Explains this causes calculated value to be higher than true value.
Worked solution
a) Measurements needed: 1. Mass of metal block (kg). 2. Change in temperature (initial and final). Alternatively, energy supplied (from current, voltage, time).
b) Some of the heat is lost to the surroundings instead of being transferred to the metal block. As a result, the specific heat capacity calculated appears higher, because the actual temperature rise is less than it would be if all the energy went into the block.