Answer:
Energy lost by the water is 17.1 x 10³ J .
Step-by-step explanation:
Specific heat is defined as the amount of energy per unit mass needed to raise the temperature of the substance by a one degree Celsius.
Heat energy gain or loss by any substance is given by :
Q = m x C x ( T₁ - T₂ ) .....(1)
Here m is the mass of the substance, C is specific heat of the substance and T₁ and T₂ are the initial and final temperature of the substance.
According to the problem,
Mass of water, m = 190 gm
Specific heat of water, C = 4.186 J gm⁻¹ ⁰C⁻¹
Initial temperature, T₁ = 42.7⁰ C
Final temperature, T₂ = 21.2⁰ C
Substitute these values in equation (1).
Heat energy loss by water = 190 x 4.186 x ( 21.2 - 42.7 )
= -17.1 x 10³ J
In the above value, negative sign denotes the loss in energy.