question archive 1)A student makes a phosphoric acid - dihydrogen phosphate buffer (H3PO4 / H2PO4-) with an initial pH of 1
1)A student makes a phosphoric acid - dihydrogen phosphate buffer (H3PO4 / H2PO4-) with an initial pH of 1
Subject:ChemistryPrice: Bought3
1)A student makes a phosphoric acid - dihydrogen phosphate buffer (H3PO4 / H2PO4-) with an initial pH of 1.92 and equal concentrations of the two buffer components. The effective pH range of this buffer covers from pH (?) on the acidic side to pH (?) on the basic side. The amount of strong acid this buffer can neutralize is (?) moles/L buffer. 2) The student dilutes 50.0 mL the H3PO4 / H2PO4- buffer (from the previous question) with 50.0 mL of water. Will the pH of the buffer change noticeably? Will increase/ will decrease/stay the same? Will the buffer capacity change noticeably? Will increase/ will decrease/stay the same? 3) A different student makes a buffer with 0.3758 M dihydrogen phosphate ion and 0.4729 M hydrogen phosphate ion. Phosphoric acid (H3PO4) has values of Ka1 = 1.20×10-2, Ka2 = 1.95×10-7, and Ka3 = 3.02×10-12. What is the pH of the buffer just described? 4) Calculate the new pH if 0.02400 mol HCl is added to exactly 1.000 L of the buffer in the previous question (0.3758 M dihydrogen phosphate ion and 0.4729 M hydrogen phosphate ion). In the lab, if we use concentrated 12 M HCl the volume added to deliver 0.02400 mol is about 2 mL, so assume we can ignore any change in volume for this question. What is the new pH after adding the HCl
