{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

F09_230_L9pre[1]

# F09_230_L9pre[1] - CHEM 230 F09 Lecture 9 Chapter 6...

This preview shows pages 1–9. Sign up to view the full content.

CHEM 230 F09 Lecture 9 Chapter 6: Thermodynamics First Law Session ID: 230 Homework 2 due Wed 9/30 at 10pm

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
a) C12H22O11(s) 12 C(s) + 11 H2O(g) + heat b) heat + 2KClO3(s) 2 KCl(s) + 3O2(g) b) C(s) + O2(g) CO2(g) + heat H2SO4 C Self-Lighting Candle Frozen Beaker Heat + Ba(OH)2° 8H2O(s) + 2NH4SCN(s) Ba(SCN)2(s) + 2NH3(g) + 10 H2O(l) http://www.youtube.com/watch? v=vgh76gPSg3M
Measuring Enthalpy Heat exchange: Temperature change q = mC T qa= -qb Phase change Hvap, Hfus Measure with calorimeter Reactions Themochemical equations (adding, reversing, stoichiometry) Hess’s Law Heats of formation Bond enthalpy

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Calorimetry Calorimeter: device used to measure the heat absorbed or evolved during a physical or chemical change Constant volume: measures U = qv Constant pressure: measures H = qp = heat of reaction
Problem A calorimeter with heat capacity equivalent to 0.739 grams of water is used to measure the heat of combustion of 0.303 g of sucrose (C12H22O11 MW = 342 g/mol). The temperature increase was found to be 5.00oC. Calculate the would be released by this reaction C12H22O11 (s) + O2(g) g CO2(g) + H2O(g) qrxn = -qCal = -mCH2O T = -0.739g (4.184 J )(+5oC) goC = -15.46 J Cs,H2O = 4.184 J/goC

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Concept Question Is the energy that we just calculated, the energy associated with the combustion reaction as written? A calorimeter with heat capacity equivalent to 0.739 grams of water is used to measure the heat of combustion of 0.303 g of sucrose (C12H22O11 MW = 342 g/mol). The temperature increase was found to be 5.00oC. Calculate the would be released by this reaction C12H22O11 (s) + O2(g) L CO2(g) + H2O(g) Hrxn= - 15.46 J? Yes or No
Thermochemical Equations C(s, graphite) + O2(g)→ CO2(g) ΔH = -393.509 kJ 2C(s, graphite) + 2O2(g)→ 2CO2(g) ΔH = -787.018 kJ (*2) 4C(s, graphite) + 4O2(g)→ 4CO2(g) ΔH = -1574.04 kJ (*4) CO2(g) → C(s, graphite) + O2(g) ΔH = 393.509 kJ (reversed) Which are exothermic, which endothermic?

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Assuming gasoline and diesel engines consume the same number of moles of fuel, and lose the same amount of
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern