Chemistry 104 Laboratory
	This Week
Answer Keys Gen Chem Lab Periodic Table	· Quiz 2: Expt 2 (Part C), Expt 3 · Expt 1: Brita, Scum, and Scale (Week 2 – Parts B,C) · Report o Procedure, Data for B, C due today o Remainder of report due in two days
	Next Time
	· Expt 4: Understanding and Predicting Acid-Base Behavior
	Notes for Today
	The Brita Filtration Process Cation exchange on the filter: 2(R-SO3^-)(resin cation)^+(s) + M^2+(aq) --> (R-SO3^-)2 M^2+(s) + 2(resin cation)^+ (aq) Some Questions About Brita Water Softening Is the Brita filter effective in softening tap water (removing Ca^2+, Mg^2+)? Does the softening capacity change over time? What resin cations are released to the water? What are their concentrations? Tasks For Today Measure hardness ([M^2+]) of unfiltered tap water using EDTA (Y^4-) titration M^2+(aq) + Y^4-(aq) --> MY^2-(aq) Titrate M^2+ in unfiltered water Endpoint detection by spectrophotometry What must you measure/know to calculate [M^2+]? Graphical analysis (Excel) of pH, IC data for unfiltered and filtered tap water pH measurement gives [H^+] Ion chromatography gives [Ca^2+], [Mg^2+], [Na^+], [K^+] What does it mean if a cation concentration changes relative to its initial tap water concentration? Graph [cation] vs. volume filtered to answer questions (noted above and in Writing Your Report)