Question

Hydrochloric acid reacts with barium hydroxide according to the equation: 2HCl(aq)+Ba(OH)₂(aq)→BaCl₂(aq)+2H₂O(l) (l) Δh = -118 kj calculate the heat (in kj) associated with the complete reaction of 36.5 grams of HCl (aq).

a. -236
b. 118
c. -59.1
d. -118
e. none of the above

Answer 1

The heat associated with the reaction of 36.5 grams of HCl with barium hydroxide is -59.1 kJ, which is half the heat released for 2 moles according to the thermochemical equation, making option c the correct answer.

Step-by-step explanation:

The question involves the calculation of the heat associated with the complete reaction of 36.5 grams of HCl in an exothermic reaction with barium hydroxide. First, we need to calculate the number of moles of HCl in 36.5 grams. The molar mass of HCl is 1 (hydrogen) + 35.5 (chlorine) = 36.5 g/mol. Therefore, 36.5 grams correspond to exactly 1 mole of HCl.

According to the given thermochemical equation, the reaction of 2 moles of HCl releases -118 kJ of heat. Since we have 1 mole of HCl reacting, we expect half the amount of heat to be released. Therefore, the heat associated with the reaction of 36.5 grams of HCl is:

-118 kJ/2 = -59 kJ

So, the correct answer is -59.1 kJ (rounded to three significant figures), which corresponds to option c.