Double replacement reactions involve the swapping of elements between two different compounds.
The general formula is:
WX + YZ → WZ + YX
or
compound + compound → new compound + new compound
This is analogous to two dancing couples switching partners,
Some lone elements are “special” and will be found as diatomics or polyatomics: H2, O2, N2, F2, Cl2, Br2, I2, P4, S8.
All other elements are monatomics: Fe, Ca, Li, etc.
Remember: Elements combined in compounds use their valances to determined the ratios in a compound.
Practice Questions:
For each of the following (a) complete the word equation, (b) create a balanced equation.
(a) barium iodide + silver sulfide →
(b) sodium chloride + tin (II) bromide →
(c) lead (II) sulfide + aluminum fluoride →
Answers:
(a) barium iodide + silver sulfide → barium sulfide + silver iodide
BaI2 + 2AgS → 2BaS + Ag2S
(b) sodium chloride + tin (II) bromide → tin(II) chloride + sodium bromide
2NaCl + SnBr2 → SnCl2 + 2NaBr
(c) lead (II) sulfide + aluminum fluoride → aluminum sulfide + lead (II) fluoride
3PbS + 2AlF3 → Al2S3 + 3PbF2
Homework:
Answers:
