Question

1. h₂o₂ → h₂o + __o₂
2. al + cl₂ → __alcl₃
3. ag₂o → ag + __o₂
4. h₂ + n₂ → __nh₃
5. ca + h₂o → ca(oh)₂ + h₂
6. secl₆ + o₂ → seo₂ + cl₂
7. ch₄ + o₂ → co₂ + h₂o
8. kclo₃ → kcl + __o₂
9. s₈ + o₂ → __so₂
10. p₄ + o₂ → __p₂o₅
11. na + h₂o → naoh + h₂
12. no + o₂ → __no₂
13. fecl₂ + cl₂ → __fecl₃
14. cro₃ → cr₂o₃ + __o₂
15. agbr + gapo₄ → ag₃po₄ + gabr₃
16. al + fe₂o₃ → fe + al₂o₃
17. kno₃ + h₂co₃ → k₂co₃ + hno₃
18. sicl₄ + h₂o → sio₂ + hcl
19. h₃po₄ + hcl → pcl₅ + h₂o
20. pb(no₃)₂ + nai → pbi₂ + nano₃
21. al + h₂so₄ → al₂(so₄)₃ + h₂

Explanation:

Step1: Balance equation 9: Ca, H, O

Balance Ca first: $1\text{Ca} + \text{__H}_2\text{O}
ightarrow 1\text{Ca(OH)}_2 + \text{__H}_2$
Balance O: $1\text{Ca} + 2\text{H}_2\text{O}
ightarrow 1\text{Ca(OH)}_2 + \text{__H}_2$
Balance H: $1\text{Ca} + 2\text{H}_2\text{O}
ightarrow 1\text{Ca(OH)}_2 + 1\text{H}_2$

Step2: Balance equation10: Se, Cl, O

Balance Se first: $1\text{SeCl}_6 + \text{__O}_2
ightarrow 1\text{SeO}_2 + \text{__Cl}_2$
Balance Cl: $1\text{SeCl}_6 + \text{__O}_2
ightarrow 1\text{SeO}_2 + 3\text{Cl}_2$
Balance O: $1\text{SeCl}_6 + 1\text{__O}_2
ightarrow 1\text{SeO}_2 + 3\text{Cl}_2$

Step3: Balance equation11: C, H, O

Balance C first: $1\text{CH}_4 + \text{__O}_2
ightarrow 1\text{CO}_2 + \text{__H}_2\text{O}$
Balance H: $1\text{CH}_4 + \text{__O}_2
ightarrow 1\text{CO}_2 + 2\text{H}_2\text{O}$
Balance O: $1\text{CH}_4 + 2\text{O}_2
ightarrow 1\text{CO}_2 + 2\text{H}_2\text{O}$

Step4: Balance equation12: K, Cl, O

Balance K/Cl first: $2\text{KClO}_3
ightarrow 2\text{KCl} + \text{__O}_2$
Balance O: $2\text{KClO}_3
ightarrow 2\text{KCl} + 3\text{O}_2$

Step5: Balance equation13: S, O

Balance S first: $1\text{S}_8 + \text{__O}_2
ightarrow 8\text{SO}_2$
Balance O: $1\text{S}_8 + 8\text{O}_2
ightarrow 8\text{SO}_2$

Step6: Balance equation14: P, O

Balance P first: $1\text{P}_4 + \text{__O}_2
ightarrow 2\text{P}_2\text{O}_5$
Balance O: $1\text{P}_4 + 5\text{O}_2
ightarrow 2\text{P}_2\text{O}_5$

Step7: Balance equation15: Na, H, O

Balance Na first: $2\text{Na} + \text{__H}_2\text{O}
ightarrow 2\text{NaOH} + \text{__H}_2$
Balance H/O: $2\text{Na} + 2\text{H}_2\text{O}
ightarrow 2\text{NaOH} + 1\text{H}_2$

Step8: Balance equation16: N, O

Balance N first: $2\text{NO} + \text{__O}_2
ightarrow 2\text{NO}_2$
Balance O: $2\text{NO} + 1\text{O}_2
ightarrow 2\text{NO}_2$

Step9: Balance equation17: Fe, Cl

Balance Fe first: $2\text{FeCl}_2 + \text{__Cl}_2
ightarrow 2\text{FeCl}_3$
Balance Cl: $2\text{FeCl}_2 + 1\text{Cl}_2
ightarrow 2\text{FeCl}_3$

Step10: Balance equation18: Cr, O

Balance Cr first: $4\text{CrO}_3
ightarrow 2\text{Cr}_2\text{O}_3 + \text{__O}_2$
Balance O: $4\text{CrO}_3
ightarrow 2\text{Cr}_2\text{O}_3 + 3\text{O}_2$

Step11: Balance equation19: Ag, Ga, PO₄, Br

Balance Ag/PO₄ first: $3\text{AgBr} + 1\text{GaPO}_4
ightarrow 1\text{Ag}_3\text{PO}_4 + \text{__GaBr}_3$
Balance Ga/Br: $3\text{AgBr} + 1\text{GaPO}_4
ightarrow 1\text{Ag}_3\text{PO}_4 + 1\text{GaBr}_3$

Step12: Balance equation20: Al, Fe, O

Balance Al/Fe first: $2\text{Al} + 1\text{Fe}_2\text{O}_3
ightarrow 2\text{Fe} + 1\text{Al}_2\text{O}_3$
Balance O: $2\text{Al} + 1\text{Fe}_2\text{O}_3
ightarrow 2\text{Fe} + 1\text{Al}_2\text{O}_3$

Step13: Balance equation21: K, NO₃, CO₃, H

Balance K first: $2\text{KNO}_3 + \text{__H}_2\text{CO}_3
ightarrow 1\text{K}_2\text{CO}_3 + \text{__HNO}_3$
Balance NO₃/CO₃: $2\text{KNO}_3 + 1\text{H}_2\text{CO}_3
ightarrow 1\text{K}_2\text{CO}_3 + 2\text{HNO}_3$

Step14: Balance equation22: Si, Cl, H, O

Balance Si first: $1\text{SiCl}_4 + \text{__H}_2\text{O}
ightarrow 1\text{SiO}_2 + \text{__HCl}$
Balance Cl: $1\text{SiCl}_4 + \text{__H}_2\text{O}
ightarrow 1\text{SiO}_2 + 4\text{HCl}$
Balance H/O: $1\text{SiCl}_4 + 2\text{H}_2\text{O}
ightarrow 1\text{SiO}_2 + 4\text{HCl}$

Step15: Balance equation23: P, Cl, H, O

Balance P first: $1\text{H}_3\text{PO}_4 + \text{__HCl}
ightarrow 1\text{PCl}_5 + \text{__H}_2\text{O}$
Balance Cl: $1\text{H}_3\text{PO}_4 + 5\text{HCl}
ightarrow 1\text{PCl}_5 + \text{__H}_2\text{O}$
Balance H/O: $1\text{H}_3\text{PO}_4 + 5\text{HCl}
ightarrow 1\text{PCl}_5 + 4\text{H}_2\text{O}$

Step16: Balance equation24: Pb, I, NO₃, Na

Balance Pb first: $1\text{Pb(NO}_3\text{)}_2 + \text{__NaI}
ightarrow 1\text{PbI}_2 + \text{__NaNO}_3$
Balance I: $1\text{Pb(NO}_3\text{)}_2 + 2\text{NaI}
ightarrow 1\text{PbI}_2 + \text{__NaNO}_3$
Balance NO₃/Na: $1\text{Pb(NO}_3\text{)}_2 + 2\text{NaI}
ightarrow 1\text{PbI}_2 + 2\text{NaNO}_3$

Step17: Balance equation25: Al, SO₄, H

Balance Al first: $2\text{Al} + \text{__H}_2\text{SO}_4
ightarrow 1\text{Al}_2(\text{SO}_4\text{)}_3 + \text{__H}_2$
Balance SO₄: $2\text{Al} + 3\text{H}_2\text{SO}_4
ightarrow 1\text{Al}_2(\text{SO}_4\text{)}_3 + \text{__H}_2$
Balance H: $2\text{Al} + 3\text{H}_2\text{SO}_4
ightarrow 1\text{Al}_2(\text{SO}_4\text{)}_3 + 3\text{H}_2$

Answer:

1. $\boldsymbol{1\text{Ca} + 2\text{H}_2\text{O}

ightarrow 1\text{Ca(OH)}_2 + 1\text{H}_2}$

1. $\boldsymbol{1\text{SeCl}_6 + 1\text{O}_2

ightarrow 1\text{SeO}_2 + 3\text{Cl}_2}$

1. $\boldsymbol{1\text{CH}_4 + 2\text{O}_2

ightarrow 1\text{CO}_2 + 2\text{H}_2\text{O}}$

1. $\boldsymbol{2\text{KClO}_3

ightarrow 2\text{KCl} + 3\text{O}_2}$

1. $\boldsymbol{1\text{S}_8 + 8\text{O}_2

ightarrow 8\text{SO}_2}$

1. $\boldsymbol{1\text{P}_4 + 5\text{O}_2

ightarrow 2\text{P}_2\text{O}_5}$

1. $\boldsymbol{2\text{Na} + 2\text{H}_2\text{O}

ightarrow 2\text{NaOH} + 1\text{H}_2}$

1. $\boldsymbol{2\text{NO} + 1\text{O}_2

ightarrow 2\text{NO}_2}$

1. $\boldsymbol{2\text{FeCl}_2 + 1\text{Cl}_2

ightarrow 2\text{FeCl}_3}$

1. $\boldsymbol{4\text{CrO}_3

ightarrow 2\text{Cr}_2\text{O}_3 + 3\text{O}_2}$

1. $\boldsymbol{3\text{AgBr} + 1\text{GaPO}_4

ightarrow 1\text{Ag}_3\text{PO}_4 + 1\text{GaBr}_3}$

1. $\boldsymbol{2\text{Al} + 1\text{Fe}_2\text{O}_3

ightarrow 2\text{Fe} + 1\text{Al}_2\text{O}_3}$

1. $\boldsymbol{2\text{KNO}_3 + 1\text{H}_2\text{CO}_3

ightarrow 1\text{K}_2\text{CO}_3 + 2\text{HNO}_3}$

1. $\boldsymbol{1\text{SiCl}_4 + 2\text{H}_2\text{O}

ightarrow 1\text{SiO}_2 + 4\text{HCl}}$

1. $\boldsymbol{1\text{H}_3\text{PO}_4 + 5\text{HCl}

ightarrow 1\text{PCl}_5 + 4\text{H}_2\text{O}}$

1. $\boldsymbol{1\text{Pb(NO}_3\text{)}_2 + 2\text{NaI}

ightarrow 1\text{PbI}_2 + 2\text{NaNO}_3}$

1. $\boldsymbol{2\text{Al} + 3\text{H}_2\text{SO}_4

ightarrow 1\text{Al}_2(\text{SO}_4\text{)}_3 + 3\text{H}_2}$

(Verified balanced coefficients for pre-filled questions 5-8:

1. $\boldsymbol{2\text{H}_2\text{O}_2

ightarrow 2\text{H}_2\text{O} + 1\text{O}_2}$ (correct)

1. $\boldsymbol{2\text{Al} + 3\text{Cl}_2

ightarrow 2\text{AlCl}_3}$ (correct)

1. $\boldsymbol{2\text{Ag}_2\text{O}

ightarrow 4\text{Ag} + 1\text{O}_2}$ (correct)

1. $\boldsymbol{3\text{H}_2 + 1\text{N}_2

ightarrow 2\text{NH}_3}$ (correct))