Single Displacement and Double Displacement Reactions

In single displacement reactions, one element takes the place of (displaces) another element in a compound. general equations: A + BX  AX + B or AX + Y  AY + X example: Mg (s) + 2HCl (aq)  MgCl 2(aq) + H 2(g)

In a double displacement reaction, the cations of two different compounds exchange places, forming two new compounds. general equation: WX + YZ  WZ + YX example: Ba(OH) 2(aq) + Na 2 SO 4(aq)  BaSO 4(s) + 2NaOH (aq)

Acids and bases are chemical compounds. When they react together, they both lose their properties. The reaction between an acid and a base is a special kind of double displacement reaction called neutralization. example: NaOH (aq) + HCl (aq)  NaCl (aq) + H 2 O ( l )

Practice Questions: Write skeleton equations for the following. Then tell if the reaction is single or double displacement. Finally, balance the equation.

potassium + water  potassium hydroxide + hydrogen gas Skeleton equation: K + H 2 O  KOH + H 2 single or double displacement? Single Displacement Reaction balanced equation: __K + __H 2 O  __KOH + __H 2 2K + 2H 2 O  2KOH + H 2

zinc + tin(II)chloride  zinc chloride + tin Skeleton equation: Zn + SnCl  ZnCl+ Sn single or double displacement? Single Displacement Reaction __Zn + __SnCl  __ZnCl + __Sn Zn + SnCl  ZnCl + Sn (balanced)

potassium iodide + lead(II) nitrate  potassium nitrate + lead(II) iodide skeleton equation: KI + Pb(NO 3 ) 2  K NO 3 + PbI 2 single or double displacement? Double Displacement Reaction balanced equation: __KI + __Pb(NO 3 ) 2  __KNO 3 + __PbI 2 2KI + Pb(NO 3 ) 2  2K NO 3 + PbI 2

Homework Page 189 # 1 to 5 and page 202 #1 to 4