Answers are:
1) The metals were not heated to 100°C.
2) The metals cooled before they were added to the water.
3) The thermometer was not completely submerged in the water while reading.
4) The calorimeter was not sealed properly, so heat escaped.
First Law of Thermodynamics - any heat lost by the system must be absorbed by the surroundings.
-qsystem = qsurroundings.
Heat spontaneously flows from a hotter (in this example hot metal) to a colder body (in this example water).
Student did not have mistake in determining the specific heat of metals, because there is heat lost during experiment.
Heat capacity of a sample is expressed in units of thermal energy per degree temperature (J/K).
Heat capacity is often defined relative to a unit of mass (J/kg·K or J/g·K), prefixed with the term specific.
For example, specific heat capacity of water is 4.184 J/g·K (Cp(H₂O) = 4.184 J/g·K).
