Predicting Reactions AP Style
Practice Writing Equations for Reactions: Write the equation for each reaction in
net ionic format. There is a reaction in each case. Do not balance. LINK TO
ANSWERS AT END OF PRACTICE.
1. Sodium sulfite crystals are added to water.
2. Solid potassium dichromate is added to an aqueous solution of lead (II) nitrate.
3. Calcium carbonate chips are added to excess nitric acid.
4. Hydrogen sulfide gas is bubbled through a solution of cadmium nitrate.
5. Solutions of acetic acid and sodium carbonate are mixed.
6. Hydrogen chloride gas is bubbled through water.
7. Solutions of carbon dioxide gas and ammonia gas are mixed.
8. Solid lithium oxide is added to water.
9. Sulfur trioxide gas is bubbled through a solution of sodium hydroxide.
10. A mixture of the solid calcium oxide and solid tetraphosphorous decaoxide is
heated.
11. Solid magnesium carbonate is heated in a crucible.
12. Solid phosphorus trichloride is added to water.
13. Solid sodium cyanide is added to water.
14. Solid zinc nitrate is treated with excess sodium hydroxide solution.
15. An aqueous solution of diamminesilver chloride is treated with dilute nitric acid.
16. A suspension of copper(II) hydroxide in water is treated with an excess of
ammnonia
17. Gaseous boron hydride gas is mixed with ammonia gas
18. Boron trifluoride is added to gaseous trimethylamine
19. Gaseous silane (SiH4) is burned in excess oxygen.
20. Magnesium ribbon is burned in pure nitrogen gas.
21. An aqueous hydrogen peroxide solution is added to an acidified solution of
potassium iodide.
22. Dilute potassium permanganate solution is added to an oxalic acid solution which
was acidified with a few drops of sulfuric acid.
23. A solution containing tin (II) ion is added to acidified potassium dichromate.
24. A segment of copper wire is added to dilute nitric acid.
25. Sodium dichromate solution is added to acidified solution of sodium iodide.
26. Sodium hydride crystals are added to water.
27. Powdered iron is added to a solution of iron (II) sulfate.
28. Chlorine gas is bubbled through a solution of potassium bromide.
29. Solid sodium is added to water.
30. A dilute solution of sulfuric acid is electrolyzed between platinum electrodes.
ANSWERS TO PREDICTING EQUATIONS
1. Na2SO3 + H2O  Na+ + HSO3- + OH- soluble salt forms a weak base SO3- ( anion
from weak acids) Hydrolysis
2. Cr2O7 + Pb2+  PbCr2O7 double displacement forms precipitant
3. CaCO3 + H+  Ca2+ + CO2 + H2O double displacement gas forming carbonic acid
decomposes in water to form water and carbon dioxide
4. Cd2+ + H2S  CdS + H+ displacement forming a precipitant
5. HC2H3O2 + HCO3-  C2H3O2- + CO2 + H2O displacement acid- base
6. HCl + H2O  H3O+ + Cl- displacement acid-base
7. CO2 + H2O + NH3  NH4+ + HCO3- carbonic acid in water write carbon dioxide
and water displacement acid-base
8. Li2O + H2O  Li+ + OH- metal oxides and water form metallic hydroxides
combination
9. SO3 + OH-  HSO4- combination nonmetal oxide and water form nonbinary acids
10. CaO + P4O10  Ca3(PO4)2 combination metal oxide and nonmetal oxide forms
nonbinary salt
11. MgCO3  MgO + CO2 decomposition
12. PCl3 + H2O  H+ + Cl- + H3PO3 hydrolysis does not fit pattern exactly
13. NaCN + H2O  HCN + Na+ + OH- hydrolysis CN- is a base because it is an cation
from a weak acid
14. Zn(NO3)2 + OH-  Zn(OH)42- + NO3- formation of complex ion ~ key words
"excess sodium hydroxide"
15. Ag(NH3)+ + Cl- + H+  AgCl + NH4+ breakup of complex ion achieved by adding an
acid that reacts with the basic ligand
16. Cu(OH)2 + NH3  Cu(NH3)42+ + OH- formation of complex ion ~ key word "excess
ammonia"
17. BH3 + NH3  BH3NH3 Lewis acid base ~ coordinate covalent bond
18. BF3 + (CH3)3N  F3BN(CH3)3 Lewis acid base ~ coordinate covalent bond
19. SiH4 + O2  SiO2 + H2O combustion forms oxides of elements
20. Mg + N2  Mg3N2 synthesis, combination
21. H2O2 + H+ + I-  H2O + I2 redox
22. MnO4- + H+ + H2C2O4  Mn2+ + CO2 +H2O redox
23. Sn2+ + H+ Cr2O72-  Sn4+ + Cr3+ + H2O redox remember to add H2O to have H’s
and O's on both sides of the equation
24. Cu + H+ + NO3-  Cu2+ + NO + H2O redox
25. Cr2O7
2-
+ H+ + I-  Cr3+ + I2 + H2O redox
26. NaH + HOH  Na+ + OH- + H2 metal hydrides react with water to form metallic
hydroxides and hydrogen
27. Fe + Fe3+  Fe2+ redox intermediate ox state
28. Cl2 + Br-  Cl- + Br2 single displacement nonmetal displaces nonmetal
29. Na + HOH  Na+ + OH- + H2 single displacement metal displaces metal
30. H2O  H2 + O2 electrolysis