More Challenging Questions These questions require more thought and integrate several c...

More Challenging Questions

These questions require more thought and integrate several concepts.

A student had five beakers, each containing 100. mL of 0.500-M NaOH(aq) and all at room temperature (20.0 °C). The student planned to add a carefully weighed quantity of solid ascorbic acid, C₆H₈O₆, to each beaker, stir until it dissolved, and measure the increase in temperature. After the fourth experiment, the student was interrupted and called away. The data table looked like this:

(a) Predict the temperature the student would have observed in experiment 5. Explain why you predicted this temperature.

(b) For each experiment indicate which is the limiting reactant, sodium hydroxide or ascorbic acid.

(c) When ascorbic acid reacts with NaOH, how many hydrogen ions are involved? One, as in the case of HCl? Two, as in the case of H₂SO₄? Or three, as in the case of phosphoric acid, H₃PO₄? Explain clearly how you can tell, based on the student’s calorimeter data.