ENVY 27 Chap. 6 Microsoft Edge https://session.masteringchemistry.com G Google ,
ID: 551048 • Letter: E
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ENVY 27 Chap. 6 Microsoft Edge https://session.masteringchemistry.com G Google , YouTube Myumdsor-Blackboard M Gmail @ Pearson G Chegg Tin hark-CIBC n (6) Facebook Chap 6 ± Calorimetry Microsoft VVMedia previous 2 of 8 nex t Calorimetry Part A A calorimeter is an insulated device in whicha chemical reaction is contained. By measuring the temperature change, AT we can calculate the heat released or absorbed during the r using the following equation A calorimeter contains 210 mL of water at 12 0C. When 2 20 g of X (a substance with a molar mass of 68 0 g/mol ) is added it dissolves via the reaction X(s) H200)+X(aq) and the temperature of the solution increases to 30.0 °C Calculate the enthalpy change, for this reaction per mole of X Assume that the specific heat of the resulting solution is equal to that of water [418 J/(g·°C), that density of water is 1,00 g/ml, and that no heat is lost to the calorimeter itself nor to the surroundings Express the change in enthalpy in kilojoules per mole to three significant figures Hints q = specific heat × mass × T Or, if the calorimeter has a predetermined healt capacity. C, the equation becomes At constant pressure, the enthalpy change for the reaction. AFl, is equal to the heat. g, that is but it is usually expressed per mole of reactant and with a sign opposite to that of q for the surroundings. The total internal energy change E (sometimes referred to as ), is the sum of heat q and AH 5.40-10 k.J/mol work done, u Submit My Answers Give Up However, at constant volume (as with a bomb calorimeter) w = 0 and so E- Incorrect, One attempt remaining; Try Again Part B Consider the reaction CaHzOu (s) +120(g)12C02(g) 11HO(0) in which 10 0 g of sucrose, CaH2Ou was burned in a bomb calorimeter with a heat capacity of 7.50 kJ/°C The temperature increase inside the calorimeter was found to be 22 0 °C: Calculate the change in internal energy E for this reaction per mole of sucrose. Express the change in internal energy in kilojoules per mole to three significant figures. Hints k.J/mol Submit My Answers Give Up Provide Feedback ContinueExplanation / Answer
heat released(q) = m*s*DT
m = mass of mixer = 21*1+2.2 = 22.2 g
s = specific heat of mixer= 4.184 j/g.c
DT = 30-12 = 18
q = 22.2*4.184*18
= 1.67 kj
n = no of mol of X = 2.2/68 = 0.0323 mol
DH = -q/n
= -1.67/0.0323
= -51.7 kj/mol
part B
heat released(q) = c*DT
c= heat capacity of calorimeter = 7.5 kj/c
DT = 22 C
q = 7.5*22
= 165 kj
n = no of mol of sucrose = 10/342 = 0.0292 mol
DU = - q/n
= -165/0.0292
= -5.65*10^3 kj/mol
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