Determine whether each process is exothermic or endothermic and indicate the sign of ΔH. a. dry ice evaporating b. a sparkler burning c. the reaction that occurs in a chemical cold pack used to ice athletic injuries

Video transcript

Everyone will be given a 4.5 g sample of NAFTA line And it's burned in a bomb calorie emitter and the temperature increases from 20 to 50.37°C as complete the heat of combustion program of naphthalene and Permal of methylene. Given that the total heat capacity of the calorie emitter is 5.96. Hello joe's part degrees Celsius. We're gonna use our equation negative heat of the reaction. Because the heat of the kalorama. Ter negative heat of the reaction is the negative mass. Found the end of the other reaction and the heat of the kalorama is totally capacity of the calorie meter kinds of temperature change A mass. We have 4.5 grams and we're looking for the ndp other reaction. The total capacity of the calorie meter. 5.96 Hello joes, three degrees Celsius. Our temperature change 50. C minus 20 degrees Celsius. We're gonna get 30 .37°C. And now we're gonna plug our bodies into the equation. We're going to get negative heat of the reaction. He was a total capacity of the calorie emitter. How's the temperature change over the negative heat of the reaction? We get 5.96. Hello jules four degrees Celsius. I'm 30.37 Grace Celsius. For the heat of the reaction Get -181. Hello joes, we have the negative heat of the reaction. You can take a negative mass time to enter the other reaction Have 181 Bill jaws Equals negative 4.5 grams. Time to end the other reaction. Well, we divide both sides by negative 4.5 gramps by the end of the. Of the reaction. Going to get negative 40.2 billy Joel's program. And now I need to calculate the heat of combustion per mole of naphthalene in the smaller mass. We know that the number of malls it was a mass by the molar mass. Cover the negative heat. The reaction what? The negative number of moles. Time to end The other reaction. 181 Killer Dolls. People to negative 4.5 g by the molar mass. This is 10 Times 12011g. Eight lb. 828 17 g. Caramel has the entropy of the reaction. 181. Hello jules, -0.035 malls. The other reaction. If you divide both sides by negative 0.035 moles the entropy of the reaction We're gonna get negative 5.17. I was 10 to the third Children's promote. Thanks for watching my video and I hope it was up