00:01
Hi there.
00:02
We have a set of questions here centering around specific heat and heat capacity for water.
00:10
So starting off with letter a.
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Letter a is asking about the specific heat of liquid water.
00:16
This is a constant, so we need to look that up.
00:21
And when we look it up, we see that it is 4 .184 joules per gram degrees celsius.
00:31
Or it could be joules per gram kelvin.
00:35
Because a change in a kelvin degree and the change in a celsius degree is the same.
00:41
The two scales just start at different places.
00:45
All right, going on to letter b, the molar heat capacity of liquid water.
00:51
Again, this is another constant.
00:54
Looking this up, gives us 75 .40 joules per mole during celsius.
01:06
Since this is the molar heat capacity, it's per mole.
01:11
Degrees celsius.
01:13
All right.
01:14
So now the fun begins.
01:15
Now we get to do a little calculating because now we want to know the heat capacity of 185 grams of water.
01:28
So we have 185 grams of water.
01:32
We want to know its heat capacity.
01:34
To find that, we are going to need to use our molar heat capacity from part b.
01:40
And notice the key there is it's molar.
01:43
So we need moles of water.
01:46
So my first step here, i am going to use the molar mass of water, getting that from the periodic table, two hydrogens and one oxygen, adding them together.
01:59
That is the mass in one mole of water.
02:04
And then i can use my molar heat capacity of water.
02:13
And that is 75 .40 joules for every mole degrees celsius.
02:27
Right, so let's check out our units here.
02:29
Mole is going to cancel.
02:33
Grams, of course, cancel.
02:35
So our answer is still going to have joules per degree celsius...