Question

2litres of water at 80 degree Celsius is poured into a plastic bucket containing 10 litres of water at 20 degree Celsius.What is the final temperature of water (Density of water=1kg/litre) ( Neglect the heat gained by bucket and specific heat capacity of water=1cal/gm degree Celsius).

Answer 1

Mass of 2 Litres of water
= Volume × Density
= 2 L × 1 kg/L
= 2 kg

Mass 10 Litres of water
= Volume × Density
= 10 L × 1 kg/L
= 10 kg

Let Temperature of mixture be “T”

Heat lost by hot water = mSdT
= 2 kg × 1 cal/(g °C) × (80 - T)

Heat gain by cold water = m’SdT’
= 10 kg × 1 cal/(g °C) × (T - 20)

Heat lost by hot water = Heat gained by cold water
2 kg × 1 cal/(g °C) × (80 - T) = 10 kg × 1 cal/(g °C) × (T - 20)
80 - T = 5T - 100
6T = 180
T = 30°C

Temperature of mixture is 30°C

Answer 2

Answer:

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