What will be the final temperature of the mixture as a result of mixing 5g ice at 10 ° C with 22 g water at 30 ° C temperature ? The relative heat of ice is 0.5 cal g-l. ° C-1 .
Answers
Explanation:
Given: 5 g of ice at −10
o
C are mixed with 20g of water at 30
o
C. Specific heat of ice is 0.5 and latent heat of water 80calg
−1
.
To find the final temperature of the mixture
Solution:
We know,
Specific heat of water, s
1
=4.18J/(g
∘
C)=1cal/(g
∘
C)
As per the given condition,
Mass of ice, m
2
=5g
Mass of water, m
1
=20g
Temperature of ice, T
2
=−10
∘
C
Temperature of water, T
1
=30
∘
C
specific heat of ice, s
2
=0.5cal/g.°C
latent heat of water L=80calg
−1
.
Let the final temperature be, T
Here, Heat lost by 20g water = Heat energy needed to change the temperature of ice from –10°C to 0°C + Latent heat needed to change ice at 0°C into water at 0°C + heat absorbed by water (melted ice)
m
1
s
1
(T
1
−T)=m
2
s
2
(0−T
2
)+m
2
L+m
2
s
2
(T−T
2
)
⟹20×1×(30−T)=5×0.5(0−(−10))+5×80+5×1×(T−(0))
⟹600−20T=25+400+5T
⟹25T=600−400−25
⟹T=7
∘
C
is the final temperature