Question

# 1. Given the enthalpies of combustion of acetylene (C2H2), carbon and hydrogen,                 2 C2H2(g) + 5...

1. Given the enthalpies of combustion of acetylene (C2H2), carbon and hydrogen,

2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(l)                    ∆Ho = -2600 kJ

C(s) + O2(g) → CO2(g)                                                       ∆Ho = -394 kJ

2 H2(g) + O2 → 2 H2O(l)                                                    ∆Ho = -572 kJ

Calculate the enthalpy of formation of acetylene. The reaction is shown below.

2 C(s) + H2(g) → C2H2(g)

2.

A student carefully measures out 200.0 mL of an aqueous solution of 1.0 M HCl in a coffee cup calorimeter, sketched below. She then carefully adds 200.0 mL of 1.0 M NaOH to the calorimeter. The initial temperature for both solutions is 20.0°C. Assume that the density and specific heat of the solutions is that of water. What is the final temperature of the solution?

For this problem, assume that the calorimeter is a perfect insulator, and ignore the material out of which the calorimeter is made.

HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)         ∆H = -55.0 kJ/mol

Question 2 options:

 a. 13.4oC b. 26.6oC c. 16.7oC d. 23.3oC

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