A 2.20-g sample of phenol (C₆H₅OH) was burned in a bomb calorimeter whose total heat capacity is 11.90 kJ/°C. The temperature of the calorimeter plus contents increased from 21.50 to 27.50 °C. (b) What is the heat of combustion per mole of phenol?

Video transcript

Hi everyone for this problem, it reads a sample of an allen that weighs 3.630 g was burned in a bomb calorie meter. And the temperature of the calorie meter plus contents increased from 25.6 to 34.4 degrees Celsius, calculate the heat of combustion per mole of aniline if the total heat capacity of the calorie meter is 15.26 kg joules per degree Celsius. Okay, so our goal here for this problem is to calculate the heat of combustion. Alright, and what we're going to need to recall in order to solve this problem is the relationship between the heat of our reaction and the heat of our calorie meter. Okay, so it is our heat of reaction is equal to our heat of our calorie meter. Alright. And the heat of our reaction is equal to the heat capacity times are change in temperature. Okay. And these are going to be two important things to recall in order to solve this problem. All right. And for this specifically, were given the following values. We're told what our heat capacity of the calorie meter is. We're told that it is equal to 15.26 killer jewels per degrees Celsius. And we're told what our change in temperature is. Okay, so we're told that the temperature plus its contents is increased from 25.6 to 34. degrees Celsius. So, we need to take this difference. So we have 34.4 degrees Celsius minus 25.6 degrees Celsius is equal to 8.8 degrees Celsius. Okay, so, given that we can solve for the heat of our reaction. Okay, so using this equation here, we're going to plug in these values. Okay, so we have the heat of our reaction is going to equal negative our heat capacity of the calorie meter, which is negative 15. kg jewels per degrees Celsius. And we're going to multiply that by our change in temperature, which we just calculated at 8.8 degrees Celsius, which gives us negative .288 kila jules. Okay, so using that we now know or we now have the information that we need to calculate the heat of combustion per mole of an allen. Okay, so that value the negative 134.288 kg jules. This is per we're going to this is per the weight that was given. Okay, so that's 3.630 g. Alright, so this is per 3. g of annual in. And we're going to multiply this by our molar mass of annual in to get the heat of combustion per mole of annual in. Okay, so looking at our periodic table and one more of annual in There is 92.13 g of annual in. So we see here that our grams cancel. And we're left with killer joules per mole of annual in which is what we what we're solving for here. So when we do this calculation, we get negative kg joules per mole. And that is going to be our heat capacity or our heat of combustion per mole of annually. That is our final answer. And we can go ahead and erase the yellow on everything else. Okay, that's it for this problem. I hope this was helpful.