Answer:
1822.14 J/kg C
Explanation:
Mass of aluminum = 0.100 kg
Mass of Water = 0.250 kg
Mass of copper = 0.300 kg
Mass of unknown object = 0.70 kg
Initial temperature of Aluminum = 10 C
Initial temperature of water = 10 C
Initial temperature of copper = 30 C
Initial temperature of = 100 C
Final temperature of all substances = 20 C
Change in temperature of each of them Aluminum, water , copper and unknown material respectively = 10 C , 10 C , -10 C, -80 C respectively
Specific heat of each of them Aluminum, water , copper and unknown material respectively = 900,4186,387 and c respectively.
Heat gained by aluminum and water = (0.1)(900)(10) + (0.250)(4186)(10) = 11365 j
heat lost by copper and unknown material =(0.3)(387)(-10) = -1161
heat lost by unknown material = (0.070)(c)(-80) = -5.6 c
Now solve for c using the calorimetry principle.
Heat lost + Heat gained = 0
⇒ -5.6 c = -11365 - (-1161) = -10204 j
Specific heat of unknown material = - 10204 / -5.6
= 1822.14 j/kg C
b) Material having a specific heat of 1800 j /kg C is
Polyurethane elastomer.
