00:01
Okay, here we have a two -part question.
00:01
The first part, we're trying to find a mass of platinum.
00:04
We're totally has heat capacity of 0 .133 joules per gram c, the initial temperature 26 .3.
00:11
When we drop it, or the heat bath itself has the initial temperature 26 .3, we're going to drop in the platinum.
00:19
It goes up to 32 .8.
00:21
And the amount of energy released in this was 6 .74 joules.
00:25
What's the mass of this platinum? and so, here, we can...
00:31
See, well, we can use this equation here, where the heat is equal to mass times heat capacity times change in temperature.
00:43
So we're q, we're trying, and we're trying to find our m here.
00:48
We're giving all the other information except for m.
00:51
So what's isolate our m? right.
00:58
So now we can fill in these variables in sulfur mass.
01:01
So we have 6 .74 joules.
01:05
Heat capacity is 0 .133 jules gram c times our temperature.
01:14
Our temperature is going from 26 .3 to 32 .8.
01:19
So if you're reading the question, i'll think the heat capacity is based off the water is based off the planet itself, putting energy into it.
01:29
So we end at 32 .8 and we start at 26 .3 degrees c.
01:35
Jules cancel, c's cancel, and grams goes on top to give us our mass.
01:39
And so our mass is equal to 7 .76.
01:49
Everything is three sig figs.
01:51
This is four, so 7 .80 grams.
01:59
So there's a mass for that one.
02:01
Part b is a little harder.
02:04
Here, the mass for platinum is 54 .9 grams.
02:08
The tipger platinum is 91 .80.
02:10
We dropped that into a water bath containing 25 .6 milliliters of water.
02:15
The 2121 milliliter is equal to 1 gram of water, so we have 25 .6 grams of water.
02:21
Our initial water temperature is 19 .7, and the capacity of that is 4 .184.
02:27
What's the final temperature? well, the kilo of the water is going to be equal in opposite, the kilo of the platinum.
02:40
So the heat of the water is equal in magnitude and opposite direction of the platinum, right? it's leaving one and going into the other.
02:48
And so we can sub in this portion of the equations in, in water, c water, delta, delta t into tf.
02:58
Tf is going to be the same for both.
02:59
At equilibrium, they should both be at the same temperature.
03:02
And then t water is equal to, m platinum, c platinum, tf.
03:11
Again, the same as for the water and the t platinum.
03:16
So now what we can do, we can break, right, we have to isolate this tf by itself...