Question 405: Thermodynamics & KTG

Question

When 100 g of a liquid A at 100
o
C is added to 50 g of a liquid B at temperature 75
o
C, the temperature of the mixture becomes 90
o
C. The temperature of the mixture, if 100 g of liquid A at 100
o
C is added to 50 g of liquid B at 50
o
C, will be :

Accepted Answer

100 $$ 	imes $$ S
A
$$ 	imes $$ [100 $$-$$ 90] = 50 $$ 	imes $$ S
B
$$ 	imes $$ (90 $$-$$ 75)
2S
A
= 1.5 S
B
S
A
= $${3 \over 4}$$S
B
Now, 100 $$ 	imes $$ S
A
$$ 	imes $$ [100 $$-$$ T] = 50 $$ 	imes $$ S
B
(T $$-$$ 50)
2 $$ 	imes $$ $$\left( {{3 \over 4}} ight)$$ (100 $$-$$ T) = (T $$-$$ 50)
300 $$-$$ 3T = 2T $$-$$ 100
400 = 5T
T = 80

Answer

60
o
C

Answer

70
o
C

Answer

85
o
C

Answer

80
o
C

Thermodynamics & KTG

When 100 g of a liquid A at 100 o C is added to 50 g of a liquid B at temperature 75 o C, the temperature of the mixture becomes 90 o C. The temperature of the mixture, if 100 g of liquid A at 100 o C is added to 50 g of liquid B at 50 o C, will be :

Choose the correct answer: