200 g of water at 30 degrees C is mixed with 20 g of silver at 350 degrees C, what's the final temp?I'd really like to see all the steps so I can repeat this process with other questions on my...

200 g of water at 30 degrees C is mixed with 20 g of silver at 350 degrees C, what's the final temp?

I'd really like to see all the steps so I can repeat this process with other questions on my homework.

Asked on by ddm19

1 Answer | Add Yours

Top Answer

jerichorayel's profile pic

jerichorayel | College Teacher | (Level 2) Senior Educator

Posted on

This problem can be solved using the heat capacity.Inside the calorimeter, the temperature equilibrates. Meaning, when the water (30 degrees) is added to a hot silver (350 degrees) there will come a time that their temperature will be the same. That same temperature is called the final temperature.

Heat capacity has the formula

q = mc delta T

inside the calorimeter, we can assume that

qwater = -qsilver

applying the formula we can have;

(mc delta T)water = -(mc delta T)silver

where m= mass of the material

c = specific heat constant for the material

delta T is the change of temperature (in Kelvin)

 

We can substitute the values now. (remember we convert Celsius to Kelvin)

(200g)(4.186 J/gK)(Tf -303K) = - (20g)(.233J/gK)(Tf - 623K)

**for convenience we remove the units and we let Tf=x

200(4.186)(x-303) = - (20)(0.233)(x-623)

solve for x

837.2(x-303) = -4.66(x-623)

837.2x - 253671.6 = -4.66x + 2903.18

combine like terms

(837.2+4.66)x = 2903.18 + 253671.6

841.86x = 256574.78

x = 304.771 K or 31.8 degree Celsius


We’ve answered 318,957 questions. We can answer yours, too.

Ask a question