Answer:
d. 37 °C
Explanation:
[tex]m_{m}[/tex] = mass of lump of metal = 250 g
[tex]c_{m}[/tex] = specific heat of lump of metal = 0.25 cal/g°C
[tex]T_{mi}[/tex] = Initial temperature of lump of metal = 70 °C
[tex]m_{w}[/tex] = mass of water = 75 g
[tex]c_{w}[/tex] = specific heat of water = 1 cal/g°C
[tex]T_{wi}[/tex] = Initial temperature of water = 20 °C
[tex]m_{c}[/tex] = mass of calorimeter = 500 g
[tex]c_{c}[/tex] = specific heat of calorimeter = 0.10 cal/g°C
[tex]T_{ci}[/tex] = Initial temperature of calorimeter = 20 °C
[tex]T_{f}[/tex] = Final equilibrium temperature
Using conservation of heat
Heat lost by lump of metal = heat gained by water + heat gained by calorimeter
[tex]m_{m} c_{m} (T_{mi} - T_{f}) = m_{w} c_{w} (T_{f} - T_{wi}) + m_{c} c_{c} (T_{f} - T_{ci}) \\(250) (0.25) (70 - T_{f} ) = (75) (1) (T_{f} - 20) + (500) (0.10) (T_{f} - 20)\\T_{f} = 37 C[/tex]