Question

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

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

                C(s) + O₂(g) → CO₂(g)                                                       ∆H^o = -394 kJ

                2 H₂(g) + O₂ → 2 H₂O(l)                                                    ∆H^o = -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

Answer 1