 Okay. Let's try this one more time. Okay. So, if 0.1 moles of the ammonium chloride is dissolved into 100 grams of solvent with a specific heat of 0.800 pounds per grams times the degree Celsius, if the temperature of this solution decreases from 25 degrees to 18 degrees, how much energy is transferred in the reaction and is this reaction exothermic or anything? So, let's go ahead and label all our variables first. Okay. So, the first thing we need to do is find the mass of the solvent. Okay. That's going to be 1.00 times 10 square grams or 100 grams. The specific heat of the solvent is going to be 0.800 pounds per one gram times degree Celsius and the temperature change, of course, is going to be always the temperature final minus the temperature initial. In this case, it's going to be, the Tf is 18.0 degrees C minus 25.0 degrees C. So, the change in temperature is going to be negative 7.0 degrees C. So, already you can see that since the temperature is decreasing, this is going to be an endothermic reaction. Okay. Endothermic because the temperature is decreasing. So, all you got to do now is plug these values into the equation and, you know, the heat of the solvent, the heat transferred by the solvent is going to be the mass of the solvent times the change in temperature of the solvent times the specific heat of the solvent. So, the mass of the solvent is 1.00 times 10 square grams. The change in temperature of the solvent is negative 7.0 degrees Celsius and the specific heat of the solvent, 0.800 calories per one gram degrees Celsius. Okay? So, if we look now, we can cancel out grams, some grams, degrees Celsius, degrees Celsius and we're left with calories. So, when we do that, 1.00 times 10 square times negative 7 times 0.8. And then it gives us negative 560 dot calories. Okay? So, notice that this is the cube of the solvent. So, since it's negative, that means that the solvent is giving the reaction energy. Okay? Or the solvent is giving off energy. The reaction is exorbitant. That also says that the reaction is endothermic. Okay? The other thing that we want to know is or that we can extend this problem, if it said give it in K-cals or give it in big C-cals, we could just say that times, well, 1,000 calories per one big C-cals. Cals cancel and we get negative 0.560 nutritional or big C-cals. So, that's the cube of the solvent.