Question

Calculate the heat of mixing when 100 mL of 1.0 M HCl is mixed with 100 mL of 1.0 M NaOH at 25°C. The specific heat of the resulting solution is 4.18 J/g°C and the final temperature of the solution is 30°C. Assume the heat capacities of HCl, NaOH, and water are negligible.

Answer 1

When 100 mL of 1.0 M HCl is mixed with 100 mL of 1.0 M NaOH, the reaction that occurs is an acid-base neutralization reaction:HCl + NaOH  NaCl + H2OFirst, we need to determine the mass of the resulting solution. Since the density of water is approximately 1 g/mL, the mass of the 200 mL solution is approximately 200 g.Next, we can calculate the heat absorbed or released by the solution using the specific heat formula:q = mcTwhere q is the heat absorbed or released, m is the mass of the solution, c is the specific heat, and T is the change in temperature.T = T_final - T_initial = 30C - 25C = 5CNow, we can plug in the values:q =  200 g  4.18 J/gC  5C  = 4180 JSince the temperature of the solution increased, the heat of mixing is exothermic, and the heat released is 4180 J.