I need help on chemistry homework?

Posted on 2015-10-21 07:26:00 in Chemistry by ADDA HUNG

1. Using equations from below, determine ?H for C (diamond) ? C (graphite) (A) C (diamond) +O2 (g) ? CO2 (g) ?H = 395.4 kJ (B) 2 CO2 (g) ? 2 CO (g) + O2 (g) ?H = 566.0 kJ (C) 2 CO (g) ? C (graphite) + CO2 (g) ?H = 172.5 kJ

2. The Starship Enterprise is caught in a time warp and Spock is forced to use the primitive techniques of the 20th century to determine the specific heat capacity of an unknown mineral. The 307-g sample was heated to 98.7°C and placed into a calorimeter containing 72.4 g of water at 23.6°C (c=4.186 J/g°C). The heat capacity of the calorimeter was 15.7 J/°C. The final temperature in the calorimeter was 32.4°C. What is the specific heat capacity of the mineral?

3. One mole of propane, C3H8, is placed in an adiabatic (isolated), constant pressure combustion chamber at 25°C and allowed to react with a stoichiometric amount of oxygen and reacts to form H2O and CO2.
1 C3H8 + 5 O2 ? 4 H2O(g) + 3 CO2(g) ?HC3H8 = -103.85 kJ/mole, ?HCO2 = -393.51 kJ/mole, ?HH2O = -241.82 kJ/mole. Determine ?Hrxn

4. For problem #3, assume complete combustion, gas ideal behavior, and all heat generated for combustion will be gained by CO2 and H2O. Molar heat capacities are CCO2 = 56.91 J/mole*K and CH2O = 58.56 J/mole*K. What is the final temperature?

5. Using the information in #2 and 3 and a volume of 150L. What are the mole fractions and the partial pressures of H2O and of CO2?

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