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KYchem

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TranHung
22:59 25/02/2026

1(g)2015

There’s 263 actually.

They come from the very good commercial site: http://www.chembuddy.com/. It’s commercial, but there is a lot of trial and free stuff there (please note I have absolutely no connection in any way to it - other than me being a chemist!).

Advice. Generally, as you go down the list, the equations become bit harder. Why not choose say number 1, 25, 50, 75…. 250 to start with. Then if you want more practice, try 2, 26, 51, 76… 251 and so on.If you want to check you answer, type it out in the comments section for me to comment on.

OK, get cracking ?

  1. NaH2PO4 -> NaPO3 + H2O —> Ignore. Already balanced!
  2. H2CO3 -> H2O + CO2 —> Ignore. Already balanced!
  3. BaSO4 + H2SO4 -> Ba(HSO4)2 —> Ignore. Already balanced!
  4. CaCO3 -> CaO + CO2 —> Ignore. Already balanced!
  5. CaO + H2O -> Ca(OH)2 —> Ignore. Already balanced!
  6. H2SO3 -> H2O + SO2 —> Ignore. Already balanced!
  7. H3PO4 + Ca(OH)2 -> CaHPO4.2H2O —> Ignore. Already balanced!
  8. NaPO3 + CuO -> NaCuPO4 —> Ignore. Already balanced!
  9. SO3 + H2O -> H2SO4 —> Ignore. Already balanced!
  10. Be(OH)2 -> BeO + H2O —> Ignore. Already balanced!
  11. BaO + H2O -> Ba(OH)2 —> Ignore. Already balanced!
  12. Na2SO3 + S -> Na2S2O3 —> Ignore. Already balanced!
  13. SO2 + H2O -> H2SO3 —> Ignore. Already balanced!
  14. Li2O + H2O -> LiOH
  15. Na2HPO4 -> Na4P2O7 + H2O
  16. H4As2O7 -> As2O5 + H2O
  17. CaC2 + N2 -> CaCN2 + C —> Ignore. Already balanced!
  18. Mg(OH)2 -> (MgOH)2O + H2O
  19. HAsO3 -> As2O5 + H2O
  20. KHSO4 -> K2S2O7 + H2O
  21. H3PO4 -> H4P2O7 + H2O
  22. NaCl + NH4HCO3 -> NaHCO3 + NH4Cl —> Ignore. Already balanced!
  23. HAsO2 -> As2O3 + H2O
  24. UO3 + H2 -> UO2 + H2O —> Ignore. Already balanced!
  25. CdSO4 + H2S -> CdS + H2SO4 —> Ignore. Already balanced!
  26. HIO3 -> I2O5 + H2O
  27. Ca(HCO3)2 -> CaCO3 + CO2 + H2O —> Ignore. Already balanced!
  28. FeS + H2SO4 -> H2S + FeSO4 —> Ignore. Already balanced!
  29. (NH4)2SO4 + CaCO3 -> (NH4)2CO3 + CaSO4 —> Ignore. Already balanced!
  30. Hg2CO3 -> Hg + HgO + CO2 —> Ignore. Already balanced!
  31. CaSO4 -> CaS + O2
  32. BeF2 + Mg -> MgF2 + Be —> Ignore. Already balanced!
  33. Mg + N2 -> Mg3N2
  34. SiO2 + Ca(OH)2 -> CaSiO3 + H2O —> Ignore. Already balanced!
  35. K2O + H2O -> KOH
  36. C + H2O -> CO + H2 —> Ignore. Already balanced!
  37. Ca(OH)2 + CO2 -> Ca(HCO3)2
  38. N2O3 + H2O -> HNO2
  39. SiO2 + Na2CO3 -> Na2SiO3 + CO2 —> Ignore. Already balanced!
  40. BaO2 + H2SO4 -> BaSO4 + H2O2 —> Ignore. Already balanced!
  41. Na2Cr2O7 + S -> Cr2O3 + Na2SO4 —> Ignore. Already balanced!
  42. Ca(OH)2 + CO2 -> CaCO3 + H2O —> Ignore. Already balanced!
  43. Fe2O3 + SiO2 -> Fe2Si2O7
  44. CO2 + NH3 + H2O -> NH4HCO3 —> Ignore. Already balanced!
  45. Na2O + H2O -> NaOH
  46. NH4NO3 -> N2O + H2O
  47. N2O5 + H2O -> HNO3
  48. CaS + H2O -> Ca(OH)2 + H2S
  49. Al(OH)3 + NaOH -> NaAlO2 + H2O
  50. (CuOH)2CO3 -> CuO + CO2 + H2O —> Ignore. Already balanced!
  51. SrBr2 + (NH4)2CO3 -> SrCO3 + NH4Br
  52. H2O2 -> H2O + O2
  53. Ca(ClO3)2 -> CaCl2 + O2
  54. PCl5 + H2O -> POCl3 + HCl
  55. Zn + KOH -> K2ZnO2 + H2
  56. Al2O3 + Na2CO3 -> NaAlO2 + CO2
  57. PCl5 + KNO2 -> NOCl + POCl3 + KCl —> Ignore. Already balanced!
  58. Zn + HCl -> ZnCl2 + H2
  59. BeO + C + Cl2 -> BeCl2 + CO —> Ignore. Already balanced!
  60. AgBr + Na2S2O3 -> Na3[Ag(S2O3)2] + NaBr
  61. N2 + O2 -> N2O
  62. BeSO4 + NH4OH -> Be(OH)2 + (NH4)2SO4
  63. Cu(CN)2 -> CuCN + C2N2
  64. SiC + Cl2 -> SiCl4 + C
  65. NH3 + O2 -> HNO3 + H2O
  66. Fe2(C2O4)3 -> FeC2O4 + CO2
  67. H2 + O2 -> H2O
  68. K + Br2 -> KBr
  69. CO + O2 -> CO2
  70. HNO2 + O2 -> HNO3
  71. O2 -> O3
  72. NaHCO3 -> Na2CO3 + CO2 + H2O
  73. CO2 + NH3 -> OC(NH2)2 + H2O
  74. Xe + F2 -> XeF6
  75. MnS + HCl -> H2S + MnCl2
  76. CaC2 + H2O -> C2H2 + Ca(OH)2
  77. ClO2 + H2O -> HClO2 + HClO3
  78. CuSO4 + KCN -> Cu(CN)2 + K2SO4
  79. NaOH + FeSO4 -> Na2SO4 + Fe(OH)2
  80. Ca(OH)2 + H3PO4 -> CaHPO4 + H2O
  81. PbCrO4 + HNO3 -> Pb(NO3)2 + H2CrO4
  82. HgO -> Hg + O2
  83. (CN)2 + NaOH -> NaCN + NaOCN + H2O
  84. BaCO3 + HNO3 -> Ba(NO3)2 + CO2 + H2O
  85. H3AsO4 -> As2O5 + H2O
  86. CaO + C -> CaC2 + CO
  87. Zn(OH)2 + NaOH -> Na2ZnO2 + H2O
  88. HNO3 + P2O5 -> N2O5 + HPO3
  89. UF4 + Mg -> MgF2 + U
  90. Mn2O3 + Al -> Al2O3 + Mn
  91. MnO2 + K2CO3 + KNO3 -> K2MnO4 + KNO2 + CO2
  92. AlN + H2O -> NH3 + Al(OH)3
  93. Ca3(PO4)2 + H2SO4 -> CaSO4 + Ca(H2PO4)2
  94. S + N2O -> SO2 + N2
  95. N2 + H2 -> NH3
  96. CaCO3 + HCl -> CaCl2 + H2O + CO2
  97. As2O3 + H2O -> H3AsO3
  98. Be(OH)2 + NH4HF2 -> (NH4)2BeF4 + H2O
  99. NaOH + Zn(NO3)2 -> NaNO3 + Zn(OH)2
  100. MgNH4PO4 -> Mg2P2O7 + NH3 + H2O
  101. H3PO4 + Ca(OH)2 -> Ca(H2PO4)2 + H2O
  102. [Ag(NH3)2]Cl + HNO3 -> NH4NO3 + AgCl
  103. CaS + H2O -> Ca(HS)2 + Ca(OH)2
  104. Cu + CO2 + O2 + H2O -> CuCO3.Cu(OH)2
  105. (NH4)2BeF4 -> BeF2 + NH3 + HF
  106. Sn(OH)2 + NaOH -> Na2SnO2 + H2O
  107. NH4VO3 -> V2O5 + NH3 + H2O
  108. H3AsO3 -> As2O3 + H2O
  109. NaCl + H2SO4 -> Na2SO4 + HCl
  110. Fe(OH)3 -> Fe2O3 + H2O
  111. As2O5 + H2O -> H3AsO4
  112. NaOH + Cl2 -> NaCl + NaClO + H2O
  113. VO2Cl + NH4OH -> NH4VO3 + NH4Cl + H2O
  114. B2O3 + H2O -> H3BO3
  115. CH4 + O2 -> CO2 +H2O
  116. SiH4 + O2 -> SiO2 + H2O
  117. TiCl4 + Mg -> MgCl2 + Ti
  118. Pb(OH)2 + NaOH -> Na2PbO2 + H2O
  119. Si + NaOH + H2O -> Na2SiO3 + H2
  120. Si + S8 -> Si2S4
  121. CaS2 + O2 -> CaS2O3
  122. Na2SnO3 + H2S -> SnS2 + NaOH + H2O
  123. Na2S2 + O2 -> Na2S2O3
  124. (NH4)2Cr2O7 -> Cr2O3 + N2 + H2O
  125. HCl + K2CO3 -> KCl + H2O + CO2
  126. KClO3 -> KCl + O2
  127. Zn + NaOH + H2O -> Na2Zn(OH)4 + H2
  128. Na2CO3 + HCl -> NaCl + H2O + CO2
  129. Ca(OH)2 + P4O10 + H2O -> Ca(H2PO4)2
  130. CaS + H2O + CO2 -> Ca(HCO3)2 + H2S
  131. Sn(OH)4 + NaOH -> Na2SnO3 + H2O
  132. Na + H2O -> NaOH + H2
  133. Ca3(PO4)2 + SiO2 -> CaSiO3 + P2O5
  134. FeCl3 + NH4OH -> Fe(OH)3 + NH4Cl
  135. H3PO3 -> H3PO4 + PH3
  136. AlCl3 + AgNO3 -> AgCl + Al(NO3)3
  137. KOH + AlCl3 -> KCl + Al(OH)3
  138. H2SO4 + NaHCO3 -> Na2SO4 + CO2 + H2O
  139. SiO2 + HF -> SiF4 + H2O
  140. CaCN2 + H2O -> CaCO3 + NH3
  141. HCl + HNO3 -> NOCl + Cl2 + H2O
  142. KClO3 -> KClO4 + KCl
  143. P4 + O2 -> P2O5
  144. P4O10 + HCl -> POCl3 + HPO3
  145. Sb + O2 -> Sb4O6
  146. NH4Cl + Ca(OH)2 -> CaCl2 + NH3 + H2O
  147. KBr + Al(ClO4)3 -> AlBr3 + KClO4
  148. AgNO3 + FeCl3 -> Fe(NO3)3 + AgCl
  149. Ca3(PO4)2 + H3PO4 -> Ca(H2PO4)2
  150. POCl3 + H2O -> H3PO4 + HCl
  151. C2H5OH + O2 -> CO + H2O
  152. UO2 + HF -> UF4 + H2O
  153. Ag2S + KCN -> KAg(CN)2 + K2S
  154. C + SiO2 + Cl2 -> SiCl4 + CO
  155. PCl3 + H2O -> H3PO3 + HCl
  156. H3PO4 + (NH4)2MoO4 + HNO3 -> (NH4)3PO4.12MoO3 + NH4NO3 + H2OCORRECTION: H3PO4 + (NH4)2MoO4 + HNO3 -> (NH4)3PO4.Mo12O40 + NH4NO3 + H2ODue to the hard work of Desmond Chai Wei Hao, the error was been uncovered. My respect to him ?
  157. MnO2 + HCl -> MnCl2 + H2O + Cl2
  158. Fe2O3 + C -> CO + Fe
  159. PCl5 + P2O5 -> POCl3
  160. FeO + H3PO4 -> Fe3(PO4)2 + H2O
  161. Ca(NO3)2 -> CaO + NO2 + O2
  162. Fe + O2 -> Fe2O3
  163. Fe2O3 + H2 -> Fe + H2O
  164. FeSO4 + K3[Fe(CN)6] -> Fe3[Fe(CN)6]2 + K2SO4
  165. NH3 + O2 -> HNO2 + H2O
  166. Al + O2 -> Al2O3
  167. BaCl2 + Al2(SO4)3 -> BaSO4 + AlCl3
  168. Fe2(SO4)3 + Ba(NO3)2 -> BaSO4 + Fe(NO3)3
  169. Au2S3 + H2 -> Au + H2S
  170. Au + HCl + HNO3 -> AuCl3 + NO + H2O
  171. NiS + O2 -> NiO + SO2
  172. Al + FeO -> Al2O3 + Fe
  173. C2H5OH + O2 -> CO2 + H2O
  174. Na2O2 + H2O -> NaOH + O2
  175. Fe2O3 + CO -> Fe + CO2
  176. Pb(NO3)2 -> PbO + NO2 + O2
  177. Al2(SO4)3 + Ca(OH)2 -> CaSO4 + Al(OH)3
  178. Au2O3 -> Au + O2
  179. Ca3(PO4)2 + H2SO4 -> CaSO4 + H3PO4
  180. SiCl4 + H2O -> H4SiO4 + HCl
  181. Ca + AlCl3 -> CaCl2 + Al
  182. FeCl3 + Ca(OH)2 -> CaCl2 + Fe(OH)3
  183. Al2O3 + C + N2 -> AlN + CO
  184. NO + NaOH -> NaNO2 + H2O + N2O
  185. Pb3O4 + HNO3 -> Pb(NO3)2 + PbO2 + H2O
  186. CuSO4 + KCN -> CuCN + K2SO4 + C2N2
  187. KO2 + CO2 -> K2CO3 + O2
  188. P4O6 -> P4 + P2O4
  189. P4O10 + H2O -> H3PO4
  190. Al + KOH + H2O -> KAlO2 + H2
  191. Fe + H2O + O2 -> Fe2O3.H2O
  192. H3PO4 + HCl -> PCl5 + H2O
  193. MnO2 + KOH + O2 -> K2MnO4 + H2O
  194. K2CO3 + C + N2 -> KCN + CO
  195. PCl5 + H2O -> H3PO4 + HCl
  196. P4O6 + H2O -> H3PO3
  197. Al(OH)3 + H2SO4 -> Al2(SO4)3 + H2O
  198. Fe2(SO4)3 + KOH -> K2SO4 + Fe(OH)3
  199. Bi(NO3)3 + H2S -> Bi2S3 + HNO3
  200. V2O5 + HCl -> VOCl3 + H2O
  201. Cr(OH)3 + H2SO4 -> Cr2(SO4)3 + H2O
  202. Hg(OH)2 + H3PO4 -> Hg3(PO4)2 + H2O
  203. Fe + H2O -> Fe3O4 + H2
  204. Ca3P2 + H2O -> Ca(OH)2 + PH3
  205. H2SO4 + Al(OH)3 -> Al2(SO4)3 + H2O
  206. Al(NO3)3 + Na2CO3 -> Al2(CO3)3 + NaNO3
  207. K2MnO4 + H2SO4 -> KMnO4 + MnO2 + K2SO4 + H2O
  208. Na3AsO3 + H2S -> As2S3 + NaOH
  209. Mg3N2 + H2O -> Mg(OH)2 + NH3
  210. Fe3O4 + H2 -> Fe + H2O
  211. C2H2 + O2 -> CO2 + H2O
  212. (NH4)2Cr2O7 -> NH3 + H2O + Cr2O3 + O2
  213. C3H8 + O2 -> CO2 + H2O
  214. As + NaOH -> Na3AsO3 + H2
  215. H3BO3 + Na2CO3 -> Na2B4O7 + CO2 + H2O
  216. Al + HCl -> AlCl3 + H2
  217. V2O5 + Ca -> CaO + V
  218. H3BO3 -> H4B6O11 + H2O
  219. Na2B4O7 + HCl + H2O -> NaCl + H3BO3
  220. Pb + Na + C2H5Cl -> Pb(C2H5)4 + NaCl
  221. C2H3Cl + O2 -> CO2 + H2O + HCl
  222. CaHPO4.2H2O + NaOH + H2O -> Na2HPO4.12H2O + Ca(OH)2
  223. Ca3(PO4)2 + SiO2 -> P4O10 + CaSiO3
  224. Se + NaOH -> Na2Se + Na2SeO3 + H2O
  225. Al + NaOH + H2O -> NaAl(OH)4 + H2
  226. K3AsO4 + H2S -> As2S5 + KOH + H2O
  227. I2 + HNO3 -> HIO3 + NO2 + H2
  228. Al + NH4ClO4 -> Al2O3 + AlCl3 + NO + H2O
  229. FeS + O2 -> Fe2O3 + SO2
  230. Ca3(PO4)2 + C -> Ca3P2 + CO
  231. FeC2O4⋅2H2O + H2C2O4 + H2O2 + K2C2O4 -> K3[Fe(C2O4)3]⋅3H2O
  232. MgNH4AsO4.6H2O -> Mg2As2O7 + NH3 + H2O
  233. H2SO4 + HI -> H2S + I2 + H2O
  234. U3O8 + HNO3 -> UO2(NO3)2 + NO2 + H2O
  235. (NH4)3AsS4 + HCl -> As2S5 + H2S + NH4Cl
  236. Pb3(VO4)2.PbCl2 + HCl -> VO2Cl + PbCl2 + H2O
  237. NH3 + O2 -> NO + H2O
  238. Hg2CrO4 -> Cr2O3 + Hg + O2
  239. Al4C3 + H2O -> CH4 + Al(OH)3
  240. Ca10F2(PO4)6 + H2SO4 -> Ca(H2PO4)2 + CaSO4 + HF
  241. Ca5F(PO4)3 + H2SO4 -> Ca(H2PO4)2 + CaSO4 + HF
  242. UO2(NO3)2.6H2O -> UO3 + NO2 + O2 + H2O
  243. S8 + O2 -> SO3
  244. NH3 + NO -> N2 + H2O
  245. HClO4 + P4O10 -> H3PO4 + Cl2O7
  246. Au + KCN + O2 + H2O -> K[Au(CN)2] + KOH
  247. CO2 + H2O -> C6H12O6 + O2
  248. V2O5 + Al -> Al2O3 + V
  249. FeS2 + O2 -> Fe2O3 + SO2
  250. Si2H3 + O2 -> SiO2 + H2O
  251. P4 + H2O -> H3PO4 + H2
  252. H2S + Cl2 -> S8 + HCl
  253. C4H10 + O2 -> CO2 + H2O
  254. Ca3(PO4)2 + SiO2 + C -> CaSiO3 + P4 + CO
  255. C6H6 + O2 -> CO2 + H2O
  256. C10H16 + Cl2 -> C + HCl
  257. C7H6O2 + O2 -> CO2 + H2O
  258. C7H16 + O2 -> CO2 + H2O
  259. C7H10N + O2 -> CO2 + H2O + NO2
  260. KNO3 + C12H22O11 -> N2 + CO2 + H2O + K2CO3
  261. K4Fe(CN)6 + KMnO4 + H2SO4 -> KHSO4 + Fe2(SO4)3 + MnSO4 + HNO3 + CO2 + H2O
  262. K3[Fe(SCN)6] + Na2Cr2O7 + H2SO4 -> Fe(NO3)3 + Cr2(SO4)3 + CO2 + H2O + Na2SO4 + KNO3
  263. K4[Fe(SCN)6] + K2Cr2O7 + H2SO4 -> Fe2(SO4)3 + Cr2(SO4)3 + CO2 + H2O + K2SO4 + KNO3