Answer:
Heat Energy needed (Q) = 68250 J
Energy lost (Q') = 10500 J
Explanation:
Applying,
Q = cm(t₂-t₁)............. Equation 1
Where Q = heat energy needed, c = specific heat capacity of water, m = mass of water, t₁ = initial temperature, t₂ = final temperature.
From the question,
Given: m = 250 g = 0.25 kg, t₁ = 20.0°C, t₂ = 85.0°C
Constant: c = 4200 J/kg°C
Substitute these values into equation 1
Q = 0.25(4200)(85-20)
Q = 68250 J.
Similarly, heat lost
Q' = cm(t₁-t₂)................. Equation 2
Where Q = heat lost
Given: t₁ = 85°C, t₂ = 75°C
Substitute into equation 2
Q' = 4200(0.25)(85-75)
Q' = 10500 J
