2. Students mixed 100 grams of 20°C water with 100 grams of water at an unknown
temperature. The final mixture was 40°C. What was the unknown initial temperature of the
second water sample?



Answer :

The unknown temperature of the second sample is 80 degree C

In the law of conservation of energy, energy neither be created nor be destroyed - only it change one form to another form of energy.

Now,

Mass of the first sample of water , m1 = 100 g

Initial temperature for first sample , t1 = 20 degree C

Mass of the second sample of water , m2 = 100 g

Initial temperature of the second sample , t2 = ?

Final temperature for first sample = 40 degree C

c is known as the specific heat of the water

Now we are solving this problem the law of conservation of energy

Q(gain) = - Q(lost)

(m1c(delta t)1) = -(m2(delta t)2)

m1(Final temperature- t1) = - m2(Final temperature- t2)

t2 - Final temperature = m1(Final temperature- t1) / m2

t2 - 40 = 100 (40 - 20) / 100

t2 - 40 = 20

t2 = 20 + 40

t2 = 80 degree C

Hence, the initial temperature of second sample is 80 degree C

To know more about law of conservation of energy here :

https://brainly.com/question/20971995?referrer=searchResults

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