00:01
Hello, here we have to determine the total change in entropy, delta s, as we mix m1 of 4 .55 kg of water at 29 .5 c with m2, which is 7 .75 kg of water at 79 .5 c.
00:23
Let's do this.
00:24
First, we have to find the final temperature.
00:28
Let's do this.
00:29
Here, specific heat capacity of water m1 t final minus t1 equals to specific heat capacity of water m2 times t2 minus t final.
00:48
So now let's calculate t final.
00:51
Let's basically solve this.
00:55
Let's find t final.
02:00
This is 61 degrees c.
02:03
And now let's determine change in entropy.
02:07
That's delta s1 plus delta s2.
02:12
And here, this change in entropy can be found as following.
02:17
Delta s in principle is an integral from some temperature t initial to t final of cv over t dt.
02:33
Which is basically specific heat capacity of water times natural logarithm of t final over t initial.
02:50
And here this t is incalculated...