IONIC REACTIONS 110209 DISSOCIATION OF A SOLLUBLE SALT

IONIC REACTIONS 11/02/09 DISSOCIATION OF A SOLLUBLE SALT. 1) Soluble salts (table F) dissociate (break up) by separating into a positive and negative ions in the solvent water. 2) The ions become mobile as they dissolve and therefore able to conduct an electrical current. SKILL – WRITIND DISSOCIATIONS. STEP ONE: WRITE THE FORMULA STEP TWO: USING TABLE E AND/OR PERIODIC TABLE , OBTAIN THE CHARGES OF THE IONS OR REVERSE THE CRISS CROSS METHOD. STEP THREE: WRITE THE DISSOCIATION. Example one; Write the dissociation of KF. STEP ONE: WRITE THE FORMULA KF. STEP TWO: USING TABLE E AND/OR TABLE S, OBTAIN THE CHARGES OF THE IONS OR REVERSE THE CRISS CROSS METHOD. K is +1 as a) K+ and Fwith all F is -1 as with all group one halides in binary elements salts.

Example one; Write the dissociation of KF. STEP ONE: WRITE THE FORMULA KF. STEP TWO: USING TABLE E AND/OR TABLE S, OBTAIN THE CHARGES OF THE IONS OR REVERSE THE CRISS CROSS METHOD. a) K+ and Fb) WRITE THE DISSOCIATION REACTION, (WITH PHASES) KF(s) K+(aq) + F-(aq) OR YOU CAN “CROSS CRISS” ( THE SUBSCRIPT OF THE METAL BECOMES THE - CHARGE OF THE NONMETAL AND THE + CHARGE OF THE METAL. KF K+1 F-1 KF(s) K+(aq) + F-(aq)

Example one; Write the dissociation of Ca(NO 3)2. STEP ONE: WRITE THE FORMULA Ca(NO 3)2. STEP TWO: USING TABLE E AND/OR TABLE S, OBTAINTable THE CHARGES E gives the OF THE IONS OR REVERSE THE CRISS CROSS METHOD. charge of EACH Ca is +2 as with all group two elements - a) Ca+2 and NO 3 nitrate as -1 b) WRITE THE DISSOCIATION REACTION, (WITH PHASES) Ca(NO 3)2(s) Ca+2(aq) + 2 NO 3 -(aq) OR YOU CAN “CROSS CRISS” ( THE SUBSCRIPT OF THE METAL BECOMES THE - CHARGE OF THE NONMETAL AND THE SUNSCRIPT OF THE NONMETAL POLY-ION BECOMES THE + CHARGE OF THE METAL. Ca(NO 3)2(s) Ca+2(aq) + 2 NO 3 -(aq)

Example one; Write the dissociation of Fe(II)SO 4. Table E gives the charge of EACH sulfate as -2 STEP ONE: WRITE THE FORMULA Fe(II)SO 4. STEP TWO: USING TABLE E AND/OR TABLE S, OBTAIN THE CHARGES OF THE IONS OR REVERSE THE CRISS CROSS METHOD. Fe is +2 as with as indicated by the Roman numeral (II) a) Fe+2 and SO 4 -2 b) WRITE THE DISSOCIATION REACTION, (WITH PHASES) Fe(II)SO 4(s) Fe+2(aq) + SO 4 -2(aq) DO NOT USE THE CROSS-CRISS METHOD WITH ROMAN NUMERALS

TRY THESE NOW, WRITE DISSOCIATION K 2 Cr 2 O 7 2 K+ + Cr 2 O 72 Pb(NO 3)2 Pb+2 + 2 NO 3 Zn(III)(NO 3)3 Zn+3 + 3 NO 3 -