A coffee-cup calorimeter contains 100.0 mL of 0.300 M HCl at 20.3 °C. When 1.82 g Zn(s) is added, the temperature rises to 30.5 °C. What is the heat of reaction per mol Zn? Make the same assumptions as in Example 7-4, and also assume that there is no heat lost with the H₂(g) that escapes.

Example 7-4

In the neutralization of a strong acid with a strong base, the essential reaction is the combination of H⁺(aq) and OH^-(aq) to form water.

Two solutions, 25.00 mL of 2.50 M HCl(aq) and 25.00 mL of 2.50 M NaOH(aq), both initially at 21.1 °C, are added to a Styrofoam-cup calorimeter and allowed to react. The temperature rises to 37.8 °C. Determine the heat of the neutralization reaction, expressed per mole of H₂O formed. Is the reaction endothermic or exothermic?

Transcribed Image Text:

Zn(s) + 2H+ (aq) - 2+ Zn²+ (aq) + H₂(g)