Chemistry Question PLEASEEE help
A student decides to find the molar enthalpy for the reaction between phosphoric acid and calcium hydroxide. They have a 0.250 M solution of Ca(OH)2, which they will use; they can only find a 2.1 M stock solution of H3PO4. If they want 285 mL of a 0.31 solution of H3PO4, how many mL of the stock solution should they use to prepare their solution?
The same student decides to simply prepare a 0.28 M solution of H3PO4. How many mL of this solution are required to react stoichiometrically with 125 mL of their 0.250 M Ca(OH)2 solution?
3Ca(OH)2 (aq) + 2H3PO4 (aq) ---> Ca3(PO4)2 (s) + 6H2O (l)
Give your answer to the nearest tenth of a mL (e.g.: 52.8 mL)