A buffer is prepared by adding 150 mL of 1.0 M NaOH to 250 mL of 1.0 M NaH2PO4. How many moles of HCl must be added to this buffer solution to change the pH by 0.35 units? Assume the total volume remains unchanged at 400 mL. For H2PO4-, Ka = 6.3 × 10-8.

A50.0g sample of liquid water at 0.0 c ends up as ice at -20.0 c. how much energy is involved in this change?

Which one of the following bonds would you expect to be the most polar? a) b–h b) n–h c) p–h d) al–h e) c–h

With the largest atoms and the smallest number of valence electrons and with the smallest atoms and the greatest number of valence electrons are the most reactive. a. nonmetals; metals b. nonmetals; transition elements c. transition elements; metals d. metals; nonmetals