M3 Exam- Requires Respondus LockDown Browser

Attempt Time Score LATEST Attempt 1 120 minutes 78 out of 100 Score for this quiz: 78 out of 100 Submitted Sep 6 at 10:59am This attempt took 120 minutes. Question 1 0 / 10 pts Click this link to access the Periodic Table. This may be helpful throughout the exam. A reaction between HCl and NaOH is being studied in a styrofoam coffee cup with a lid and the heat given off is measured by means of a thermometer immersed in the reaction mixture. Enter the correct thermochemistry term to describe the item listed. 1. The calorimeter and mixture of HCl + NaOH 2. The air above the cup Your Answer: 1 . Adiabatic system because there is transfer of heat between the mixture of HCl and NaOH to the calorimeter 2. Vapor pressure 1. With lid = closed system 2. The air above the cup = Surroundings Question 2 10 / 10 pts Click this link to access the Periodic Table. This may be helpful throughout the exam. 1. Show the calculation of the final temperature of the mixture when a 42.7 gram sample of water at 82.1oC is added to a 18.5 gram sample of water at 20.6oC in a coffee cup calorimeter. c (water) = 4.184 J/g oC 2. Show the calculation of the energy involved in freezing 75.4 grams of water at 0oC if the Heat of Fusion for water is 0.334 kJ/g Your Answer: 1. m1= 42.7 g T1 = 82.1 m2 = 18.5 g T2 = 20.6 Heat lost = Heat gained Let Tf be the final temperature m1c (T1 - T f ) = m2c (Tf - T2) 42.7 g × 4.184 J / g ∘ C ( 82.1 ∘ C − T ) = 18.5 g × 4.184 J / g ∘ C ( T − 20.6 ∘ C ) ( 42.7 g × 4.184 J g ∘ C ) ( 18.5 g × 4.184 J g ∘ C ) × ( 82.1 ∘ C − T ) = ( T − 20.6 ∘ C )