Double Replacement Prediction I can predict the two products that will be created from a double replacement reaction

Identification from Reactants Two compounds

Prediction of Products Switch the anions First with the last, inside back – Like FOIL in math. ALWAYS put the CATION FIRST

Iron (III) hydroxide + sodium phosphate Write the formulas for the reactants

Iron (III) hydroxide + sodium phosphate Fe +3 (OH - ) 3(aq) + Na + 3 PO 4 -3 (aq)  Predict the products

Iron (III) hydroxide + sodium phosphate Fe(OH) 3 + Na 3 PO 4  Fe +3 PO Take the subscript along because it is part of what makes phosphate phosphate. Phosphate is PO 4 -3 First with last

Iron (III) hydroxide + sodium phosphate Fe(OH) 3(aq) + Na 3 PO 4(aq)  FePO 4 + Na + OH - Put the cation first and then the anion. Balance their charges. Do not carry along these subscripts! They are here to balance the charges in these compounds. Inside, back

Iron (III) hydroxide + sodium phosphate Fe(OH) 3(aq) + Na 3 PO 4(aq)  FePO 4 + NaOH Now balance equation: Because 3 OH as reactants need 3 NaOHs That gives 3 Na as products, which we have as reactants 3

Iron (III) hydroxide + sodium phosphate Fe(OH) 3(aq) + Na 3 PO 4(aq)  FePO 4 + NaOH 3 Iron (III) phosphate and sodium hydroxide

Aluminum sulfide + hydrochloric acid Write the formulas for the reactants

Aluminum sulfide + hydrochloric acid Al +3 2 S H + Cl -  Predict the products

Aluminum sulfide + hydrochloric acid Al 2 S 3 + HCl  Al +3 Cl Do not carry along this subscript! It is here to balance the charges in this compound. First with last

Aluminum sulfide + hydrochloric acid Al 2 S 3 + HCl  AlCl 3 + H + 2 S -2 Do not carry along this subscript! It is here to balance the charges in this compound. Put the cation first and then the anion. Balance their charges. Inside, back

Aluminum sulfide + hydrochloric acid Al 2 S 3 + HCl  AlCl 3 + H 2 S Now balance: Have 2Al as reactants, need 2 AlCl 3 Have 3 S as reactants, need 3 H 2 S That gives us 6 H and 6 Cl on the product side so need 6HCl Al 2 S 3 + 6HCl  2AlCl 3 + 3H 2 S

Aluminum sulfide + hydrochloric acid Al 2 S 3 + 6HCl  2AlCl 3 + 3H 2 S Produces aluminum chloride and dihydrogen monosulfide

Homework Complete the double replacement prediction worksheet.