Using Tables F & G
Table F problems Solubility guidelines for ionic substances in water solubility ranges from very low solubility (basically insoluble) to very soluble Use table F guidelines to predict if a given compound is soluble or insoluble
To use Table F Separate the ionic compound into the positive ion and the negative ion Scan for both in Table F Left side of Table F shows soluble compounds with exceptions Right side of Table F shows insoluble compounds with exceptions
Predict solubility of LiCl NH4F Ca(HCO3)2 BaSO4 K2CO3 CaCO3 Mg3(PO4)2 Ca(OH)2 Soluble – cmpd with a Group 1 ion Soluble – cmpd with NH4+ Soluble – cmpd with HCO3- Insoluble – sulfates with Ba+ Soluble – cmpd with a Group 1 ion Insoluble - most carbonates Insoluble – most phosphates Soluble – hydroxide with Ca+2
Why do we need to predict solubility? To determine the precipitate in a double replacement reaction
Predicting Products AgNO3(aq) + KCl(aq) ? AgCl(s) + KNO3(aq)
Table G problems Shows amount of solute or solvent required for a given amount of the other Involves setting up a proportion Precipitation problems
Problem: How much KCl will dissolve in 300 grams of water at 50C? Use the graph to set up a proportion 42 g KCl = 100 g H2O X g KCl 300 g H2O Problem:
Finding amount Solute 42 g KCl X g KCl = 100 g H2O 300 g H2O
How much H2O is required to just dissolve 200 g NaNO3 at 20C? 88 g NaNO3 = 100 g H2O 200 g NaNO3 X g of H2O
Finding amount H2O 88 g NaNO3 = 200 g NaNO3 100 g H2O X g H2O
Precipitation problems A saturated solution of KNO3 is prepared in 100 g of water at 50C and then cooled down to 10C. How much KNO3 will precipitate?
88 g KNO3 in 100 g H2O at 50C. 20 g KNO3 in 100 g H2O at 10C. 88 g – 20 g = 68 g KNO3 precipitates.