Ch. 10, 14.2, 14.3 thermodynamics                 test                   70 points                                  chemistry

Show your work in an organized manner, include (i) any relevant equation (or formula), (ii) conversion factor(s), (iii) put the proper units in your calculations and answer, and (iv) have the proper number of significant figures in your answer.

1. How much heat would be needed for 10.0 g of Ethanol, C2H5OH, at – 35 ºC goes to 85 ºC ? [20 points]

melting point = - 114 ºC
boiling point = 78 ºC

ΔHfusion = 5.02 kJ / mol
ΔHvaporization = 38.6 kJ / mol

specific heat (J / (g ºC))
solid = 0.97
liquid = 2.3
gas = 1.88

2. How much heat would be generated in the combustion of 5.0 g of butane, C4H10 ?  Assume all chemicals in the reaction are gases.  [15 points]

3. If 5.0 g solid sodium hydroxide dissolved in 55 mL water at 21ºC; what is the temperature of the water after all of the sodium hydroxide dissolves ?  [15 points]

 4. Based on the following information

            H2   +  F2  →   2 HF                                          ΔH1 = - 537 kJ

            C  +  2 F2  →  CF4                                            ΔH2 = - 680 kJ

            2 C  +  2 H2  →  C2H4                                      ΔH3 = + 52.3 kJ

find      C2H4  +  6 F2    →  2 CF4  +  4 HF                    ΔH = ?   [20 points]