 So, how much energy would be required to melt 15 grams of ice at zero degrees Celsius? And then it says the heat of fusion is 6.01 kilojoules per mole, okay? So it's asking us how much energy would be required. So remember, kilojoules is a unit of energy. Is everybody okay with that? And we've essentially got this conversion factor here is kilojoules to moles, right? Kilojoules to moles of ice. Does everybody see that? So, what we're going to do with this one is take that heat of fusion, how much energy it takes to melt something, in this case ice. And they say it's 6.01 kilojoules per mole. So let's just write this out, per one mole. And of course it's one mole of ice. This gives us the mass of ice, which is 15.5 grams of ice. So, can we get from the mass to the moles somehow? How do we do that? What is it? What is that thing called? The what? Molar mass. The molar mass, yeah, that conversion. So in this case it's 18.02 grams of ice, right? Because ice and water are the same molecule, of course. Or mole of ice. So this will give us now the number of moles of ice. And if we wanted to, we could even straight up get the energy, right? So do you see that? We can use this conversion factor as 6.01 kilojoules of energy. But we've got however many grams of ice, or however many moles of ice. So let's figure that out by 15.02. So we've got 0.8324 essentially moles of ice. And then multiply that by 6.01. And I got, so what are we looking for? Q, right? Plus 5.00 kilojoules of energy. So what about this one? Is this one flowing in or out of the system? Into the system, right? The other way you can, so you can also think dyes and stuff. Are there any questions about this one? You guys are getting it today. Good.