2 kg of water at 80° C is mixed with 3 kg of water at 20°C. Assuming

1.	2 kg of water at 80° C is mixed with 3 kg of water at 20°C. Assuming no heat losses, find the final temperature of the mixture.
Answer» m₁ = 2 kg, T₁= 80°C, s = 4.2 × 10³ J kg^-1 °C^-1, m₂ = 3kg, T₂ = 20°C Let the final temperature be T₃ Heat lost by 3 kg water = Heat gained by 2 kg water. ⇒ m₁s(T₁ – T₃) = m₂s(T₃ – T₂) ⇒ 2 × (80 – T₃) = 3 × (T₃ – 20) ⇒ T₃ = 44° C ∴ Final temperature = 44° C.

2 kg of water at 80° C is mixed with 3 kg of water at 20°C. Assuming no heat losses, find the final temperature of the mixture.

Answer»

m₁ = 2 kg,

T₁= 80°C,

s = 4.2 × 10³ J kg^-1 °C^-1,

m₂ = 3kg,

T₂ = 20°C

Let the final temperature be T₃

Heat lost by 3 kg water = Heat gained by 2 kg water.

⇒ m₁s(T₁ – T₃) = m₂s(T₃ – T₂)

⇒ 2 × (80 – T₃) = 3 × (T₃ – 20)

⇒ T₃ = 44° C

∴ Final temperature = 44° C.