Question

To prepare for a bath a boy 210 litre of cold water at 20 degree Celsius and added 2 letter of hot water at 50 degree Celsius the bucket being made of plastic 116 negligible amount of heat calculate the final temperature of mixture with density of water is 1 kg per litre

Answer 1

Explanation:

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