Chapter 1.12, Problem 36P

The dissociation of the weak acid, nitrous acid, HNO2, takes place according to the reaction: HNO2 (aq) ⇌ H+(aq) + NO2–(aq) K=7.2 X 10-4 When 1.00 mole of HNO2 is added to 1.00 L of water, the H+ concentration at equilibrium is 0.0265 M.A) Calculate the value of Q if 1.00 L of water is added? B) How will reaction shift if 1.00 L of water is added?

Suppose a certain copolymer elastomeric material “styrene-butadiene rubber”) contains styrene ("S") monomers –(C8H8)– and butadiene ("B") monomers –(C4H6)– and that their numerical ratio S:B = 1:8. What is the mass ratio mS:mB of the two monomers in the material? What is the molecular mass M of a macromolecule of this copolymer with degree of polymerization n = 60,000? Data: AC = 12.01 u, AH = 1.008 u.

Lab Questions from Lab: Gravimetric Determination of Calcium as CaC2O4•H2O What is the purpose of the methyl red indicator? Why does a color change to yellow tell you that the reaction is complete? Why is the precipitate rinsed with ice-cold water in step 4? Why not room temperature or hot water? Why is it important that the funnels be placed in a desiccator before weighing (steps 1 and 5)?