lecture6

3 kj 2ch4g 4o2g 2co2g 4h2og h 16046 kj ch4g

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Unformatted text preview: ;0 process is endothermic ∆H<0 process is exothermic CH4(g) + 2O2(g) Æ CO2(g) + 2H2O(g) ∆H = -802.3 kJ 2CH4(g) + 4O2(g) Æ 2CO2(g) + 4H2O(g) ∆H = -1604.6 kJ CH4(g) + 2O2(g) Æ CO2(g) + 2H2O(l) ∆H = -890.4 kJ ∆H = 100.0 g CH4 x 1 mol CH4 -802.3 kJ x = -5001.9 kJ ∆H is negative, so heat is released. 16.04 g CH4 1 mol CH4 Calorimetry measurement of heat flow q heat capacity C = amount of heat required to raise the temperature of a given ∆T amount of a substance 1°C Specific heat (s): amount of heat required to raise the temperature of 1 gram of a substance 1°C (see table 6.1, pg 242) q = sm∆T heat flows are measured in a device called a calorimeter. In a coffee cup calorimeter, P is constant and q = ∆H 16.69 g Fe is heated to 100.0° C and dropped into 100.0 g water initially at 15.0°C. If the final temperature of the water is 16.5° C, calculate the specific heat of the Fe. 6-3 Chapter 6 Thermochemistry -qFe = qwater -sm∆T(Fe) = sm∆T(water) -s(16.69 g)(16.5° C - 100.0° C) = (4.18 J/g ° C)(100.0 g)(16.5° C - 15.0° C) s = 0.45 J/g ° C 0....
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This note was uploaded on 04/05/2014 for the course CHEM 1211 taught by Professor Jackduff during the Spring '13 term at SPSU.

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