hangma Posted February 18, 2009 Report Share Posted February 18, 2009 I cannot do these questions. Could someone please explain? Q1) If you have a solution of 1L of H2O and 234g of NaCl, what is the osmotic pressure at STP (R-0.1 l*atm/mol*K)? a)89.54 atm b)109.2atm c)119.2atm d)218.4atm e)234.0atm Q2) What volume of HCl was added if 20 mL of 1M NaOH is titrated with 1M HCL to produce a pH=2? Thank you guys in advance. Link to comment Share on other sites More sharing options...
rla_z Posted February 18, 2009 Report Share Posted February 18, 2009 Q1: Osmotic pressure=MRT, where M is molarity, R is constant, T is temp in K There's 4 moles of NaCl, but NaCl dissociates in water so there's actually 8 moles of particles. R is given as 0.1, and T is 298 since it's STP OP=(8)(298)(0.1)=218.4 Q2: pH=2, so the concentration of H+ is 0.01. It says 20mL of 1M NaOH, which is 0.02 moles of OH. Therefore you needed to add 0.03 moles of H+ which is 30mL of HCl. Link to comment Share on other sites More sharing options...
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