DOUBLE REPLACEMENT REACTIONS

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• DOUBLE REPLACEMENT REACTIONS
• THE OBJECTIVE OF THIS POWERPOINT IS TO LEARN THE
  PROCEDURE OF PREDICTING DOUBLE REPACEMANT
  REACTIONS AND TO APPLY THIS TO THE LAB YOU
  PERFORMED.
• RESOURCESYOU WILL NEED TABLE F SOLUBILITY
  GUIDELINES, THE PERIODIC TABLE , CRISS CROSS
  METHOD AND BALANCING SKILLS.
• ASSIGNNING CHARGE RULES, CHARGE RULES YOU WILL
  NEED ARE
• GROUP ONE IS ALWAYS 1
• GROUP TWO IS ALWAYS 2
• HALIDES(HALOGENS) in binary compounds are -1 (for
  now)
• POLYATOMIC ION CHARGES ARE GIVEN ON TABLE F.
• FACTS(aq) is soluble, homologous aqueous phase.
• (s) is solid, insoluble
  (one product. must be a solid)

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EXAMPLE REACTIONS 1) FIRSTEXCHANGE THE METALS
TO GET PRODUCTS Na3 (PO4) (aq) Ba(NO3)2
(aq)? Na3 (PO4) Ba(NO3)2 ?
Ba(PO4) Na(NO3) 2) USE CRISS CROSS TO
DERIVE CORRECT SUBSCRIPS OF PRODUCTS. REMEMBER,
?SUBSCRIPTS OF ELEMENTS ARE NOT INHERETED
ACROSS THE ARROW. ?NEVER CHANGE A POLYATOMIC
ION FORMULA, HOWEVER THE SUBSCRIPT OUTSIDE OF ITS
PARENTHESIS IS NOT INHERITED.
SWITCH METALS
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• EXAMPLE REACTIONS
• 2) USE THE CRISS CROSS METHOD TO DETERMINE THE
  CORRECT SUBSCRIPTS OF THE PRODUCTS.
• Na3
  (PO4) Ba(NO3)2 ? Ba(PO4) Na(NO3)

Ba(PO4) Ba2 (PO4) -3
Ba3 (PO4)2 Barium Phosphate
Na(NO3) Na1 (NO3) -1 Na1(NO3)1
Na(NO3) Sodium Nitrate
Ba is in group 2 and is 2 each
Phosphate is -3 each (table E)
Na is in group 1 and is 1 each
NO3 is -1 from table E
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• EXAMPLE REACTIONS
• 3) THIRDWITH THE CORRECT PRODUCT SUBSCRIPTS IN
  PLACE, USE TABLE F TO DETERMINE IF ONE OF THE
  PRODUCT SALTS IS INSOLUBLE.
• Na3
  (PO4)(aq) Ba(NO3)2(aq) ? Ba3(PO4)2 (s)
  Na(NO3)(aq)
• 4) Now its time to balanceyour favorite! Use
  MINOH
• M balance metals first
• I balance polyatomic ions second

From table F all Phosphates are insoluble,
Barium is not an exception.
All nitrates are soluble, no exceptions
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• EXAMPLE REACTIONS
• 4)BALANCE( MINOH pt 1)---BALANCE METALS
• Na3 (PO4)(aq)
  Ba(NO3)2 (aq) ? Ba3(PO4)2 (s) Na(NO3)(aq)
• 4) BALANCE(MINOH pt 2)---BALANCE IONS (POLYATOMIC
  IONS)(THERE ARE NO NONMETALS TO BALANCE SO WE GO
  DIRECTLY TO IONS.)
• Na3 (PO4)(aq)
  Ba(NO3)2 (aq) ? Ba3(PO4)2 (s) Na(NO3)(aq)

3
3
3
3
2
THE COEFFICIENT 2 BALANCES THE 2 PHOSPHATES ON
THE RIGHT
6
THE COEFFICIENT 6 BALANCES THE 6 NITRATES ON
THE LEFT AND THE 6 SODIUMS ON THE LEFT. BALANCED
NOW!
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NOWDETERMINE THE IONIC REACTION DISSOCIATE THE
(aq) SALTS. 2 Na3 (PO4)(aq) 3 Ba(NO3)2
(aq) ? Ba3(PO4)2 (s) 6 Na(NO3)(aq) FINNALY
.cancel spectator ions (ones that did not change
phase) to derive NET IONIC REACTION THE NET
IONIC EQUATION IS ..
6 Na 2 (PO4)3-
3 Ba2 2 (NO3)-
?
Ba3(PO4)2 (s)
6 Na 6 (NO3)-
6 Na(aq) 2 (PO4)3-(aq)
3 Ba2 (aq) 6 (NO3)- (aq)
?
Ba3(PO4)2 (s)
6 Na (aq) 6 (NO3)- (aq)
2 (PO4)3-(aq)
3 Ba2 (aq)
?
Ba3(PO4)2 (s)