Question

9. What is the hydroxide-ion concentration in a solution formed by combining 200 mL of 0.16 M HCl with 300. mL of 0.091 M NaOH at 25°C? HCl(aq) + NaOH(aq) + NaCl(aq) + H2O(1) 10. What is the pH of a solution prepared by dissolving 0.241 L of HCl(g), measured at STP, in enough water such that the total volume of the solution is 2.00 L? (R = 0.0821 L.atm/(K.mol)) (Use gas law equation to calculate Mole of HCl dissolved in 2.00 L of water, Calculate M/L followed by using equation of ionic product (Kw = 1 x 10-14) to calculate [H.0'). 11. A 20.27 g of unknown metal carbonate (MCO) is dissolved in 500 ml of a 1.00 M HCl. The excess acid is then neutralized by 32.08 ml of 0.588 M NaOH. Identify M. (Hint: Find the molar mass of the MCO,then subtract it from mass of CO,.) 12. A 2.500 G sample of mixture of Na,Co, and NaCl is dissolved in 25.0 ml of 0.798 M HCI Some acid remains after the treatment of the sample. (a). Write the net ionic equation for the reaction of sodium carbonate with HCl acid. (b). If 28.7 ml of 0.108 M NaOH were required to titrate the excess HCI, how many moles of Na,Co, were present in the original sample? (c) What is the % of Na, Co, in original sample?

Answer 1

mmdes Ht (HCL) 2 - 0-16m x 200 ml 2 32 mmoles. mmoles 0-091m x 300-ml ? 27.3 mmoles. (NaOH) - → nacl + H₂O C F HCl + NaOH 32 mmoles 27.3 -27-3 -27.3 407 mmoles o Nadl neuted +27.3 2703 not salt effect Cat) & Cont). Cut 2 mmoles total Ht volume (Anne) 4-7 mmoles Soome z o-oorum - 0.009m com) 2 1.0x16" ко z ko o-oogum = 11-18 10th 1x1072 m) 10) moles Hal, na pu STP, Pzlatm T2 273K latm x o 2414 0-082057L-atmx 27316 molic 2 o.0108 moles Cncioz moles Mol 2 0 -0108 males Total volume 2.ool ? 0.0054om. strong nd, So dissociate completely cut o-oostom pt & tag [o-oo540) 2 (2.268) oldci a

mcg & enor che sticos Total & mules 2 Her added 1-oom x 500 ml 2 500 mmoles. mmoles of dit neuralhed by naon Ce = excess of mnoles nach z 0-588m x32.08ml 2 18.86304 mmoles 18.9 mmores ~ mmole ut reached 2 with inco Toram moles - excess mmole (5oo. – 18.97 mmoles 2 2 481., mmoles 481-1 x 103 moles. from above moles reachan meg 2 x moles Hel reacted 481-1 x 103 moles 2 2 240.55 x 103 moles mass of mo, molar mass meogo 240-55 x 10 moles 2) 20-279 molar mass 2 240-55x163 moles z) molar mass molar mass of m & mola mass = sy. 265 g/mol | ở Co - Ý 8-3 Heo ! molar mass of on a 849 - 60.0 = 24. 39 m a molar mass of mg mg , so compound is maco so unk rown metal s

na nery neuralion co? is basic anion, not & ner unic eavahas & Tcgr tant com Jorul b) mmoles Hol a 0.798 m x2r-oml 19.95 mmoles 2 mmoles Hel excess 2 mmoles Nooh HCl +noon nail tho = o-108 m x 28.7ml z 3-0 996 mmoles 23-40 mmoles mmoles ut reached with naco , ? 19.45 -3.40 2 16.55 mmoles 2 16.55x 103 moles moles wa, co present in sample a t & moes of at mass or 2 I x16 558103 moles 28-275 x 103 notes Naco z moles xmalar mass of Nalog - 8. 275x103 moles x 105.98389/90 2 0-8779 mass na co X1007 mass of sample t naco in onginal sample 0.877 2.5oog x 1007 2 35-ost 2 135-19.)