Liquid A of specific heat capacity 0.84 Jg−1k−1at a temperature of 50∘C is mixed with 200 g of a liquid B of specific heat capacity 2.1 Jg−1k−1 at 30∘C. The final temperature of mixture becomes 42∘C. The mass of liquid A (in g) will be
The correct option is B 750
Given:
Specific heat capacity of Liquid A : 0.84 Jg−1k−1
Temperature of Liquid A : 50∘C
Specific heat capacity of Liquid B : 2.1 Jg−1k−1
Temperature of Liquid B : 30∘C
Mass of Liquid B : 200 g
Change in temperature of liquid A:
ΔTA=42−50=−8∘C
Change in temperature of liquid B:
ΔTB=42−30=12∘C
Let m be the mass of liquid A.
Heat energy lost by liquid A:
H1=m×0.84×−8
Heat energy gained by 100 g of liquid B:
H2=200×2.1×(12)
NOTE: negative and positive sign only represent heat given and taken,
Assuming there is no heat loss,
Heat energy lost by A = Heat energy gained by B
H1=H2
m×0.84×8=200×2.1×12
m=750 g