Here are the balanced chemical equations for the reactions you've provided:
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ZnS + 2 HCl → ZnCl2 + H2S
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2 HCl + Cr → CrCl2 + H2
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3 Al + Fe3O4 → Al2O3 + 3 Fe
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H2 + Br2 → 2 HBr
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Na2S2O3 + I2 → 2 NaI + Na2S4O6
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2 LaCl3 + 3 Na2CO3 → La2(CO3)3 + 6 NaCl
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2 NH4Cl + Ba(OH)2 → BaCl2 + 2 NH3 + 2 H2O
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3 Ca(OH)2 + 2 H3PO4 → Ca3(PO4)2 + 6 H2O
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2 C4H10 + 13 O2 → 8 CO2 + 10 H2O
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C7H6O2 + 7 O2 → 7 CO2 + 3 H2O
Make sure to verify each equation by checking the number of atoms of each element on both sides to ensure that the equation is balanced correctly.