Question

practice: balancing equations #1
show all work on a separate sheet of paper. place coefficient final answers in the coefficients of \1\ blank

1. 4 h₂ + 2 o₂ → 2 h₂o
2. 4 h₃po₄ + 3 koh → 2 k₃po₄ + 3 h₂o
3. 6 k + 2 b₂o₃ → 3 k₂o + 2 b
4. 3 hcl + 1 naoh → 1 nacl + 1 h₂o
5. na + nano₃ → na₂o + n₂
6. c + s₈ → __ cs₂
7. na + o₂ → __ na₂o₂
8. n₂ + o₂ → __ n₂o₅
9. h₃po₄ + mg(oh)₂ → mg₃(po₄)₂ + h₂o
10. naoh + h₂co₃ → na₂co₃ + h₂o
11. koh + hbr → kbr + h₂o
12. h₂ + o₂ → __ h₂o₂
13. na + o₂ → __ na₂o
14. al(oh)₃ + h₂co₃ → al₂(co₃)₃ +
15. al + s₈ → __ al₂s₃

Explanation:

Step1: Balance equation 5

For the reaction $Na + NaNO_3
ightarrow Na_2O+N_2$, balance nitrogen first. Let the coefficients be $a$, $b$, $c$, $d$ for $Na$, $NaNO_3$, $Na_2O$, $N_2$ respectively. We have $b = 2d$ for nitrogen - balance. For sodium, $a + b=2c$ and for oxygen $3b = c$. Solving these equations gives $10Na+2NaNO_3
ightarrow 6Na_2O + N_2$.

Step2: Balance equation 6

For $C + S_8
ightarrow CS_2$, balance sulfur. Since there are 8 sulfur atoms in $S_8$, we need 4 moles of $CS_2$. So the balanced equation is $4C+S_8
ightarrow 4CS_2$.

Step3: Balance equation 7

For $Na+O_2
ightarrow Na_2O_2$, balance sodium and oxygen. We get $2Na + O_2
ightarrow Na_2O_2$.

Step4: Balance equation 8

For $N_2+O_2
ightarrow N_2O_5$, balance oxygen. Multiply $N_2O_5$ by 2 to balance oxygen atoms on both sides. We have $2N_2 + 5O_2
ightarrow 2N_2O_5$.

Step5: Balance equation 9

For $H_3PO_4+Mg(OH)_2
ightarrow Mg_3(PO_4)_2+H_2O$, balance magnesium first. Then balance phosphorus and hydrogen - oxygen. The balanced equation is $2H_3PO_4+3Mg(OH)_2
ightarrow Mg_3(PO_4)_2 + 6H_2O$.

Step6: Balance equation 10

For $NaOH + H_2CO_3
ightarrow Na_2CO_3+H_2O$, balance sodium. We get $2NaOH+H_2CO_3
ightarrow Na_2CO_3 + 2H_2O$.

Step7: Balance equation 11

For $KOH+HBr
ightarrow KBr + H_2O$, it is already balanced as $KOH + HBr
ightarrow KBr+H_2O$.

Step8: Balance equation 12

For $H_2+O_2
ightarrow H_2O_2$, we have $H_2+O_2
ightarrow H_2O_2$.

Step9: Balance equation 13

For $Na+O_2
ightarrow Na_2O$, balance sodium and oxygen. We get $4Na+O_2
ightarrow 2Na_2O$.

Step10: Balance equation 14

For $Al(OH)_3+H_2CO_3
ightarrow Al_2(CO_3)_3+H_2O$, balance aluminum first. Then balance carbon and hydrogen - oxygen. The balanced equation is $2Al(OH)_3+3H_2CO_3
ightarrow Al_2(CO_3)_3+6H_2O$.

Step11: Balance equation 15

For $Al + S_8
ightarrow Al_2S_3$, balance sulfur. We need 8 moles of $Al_2S_3$ to balance 8 moles of $S_8$. Then balance aluminum. The balanced equation is $16Al + 3S_8
ightarrow 8Al_2S_3$.

Answer:

1. $10Na+2NaNO_3

ightarrow 6Na_2O + N_2$

1. $4C+S_8

ightarrow 4CS_2$

1. $2Na + O_2

ightarrow Na_2O_2$

1. $2N_2 + 5O_2

ightarrow 2N_2O_5$

1. $2H_3PO_4+3Mg(OH)_2

ightarrow Mg_3(PO_4)_2 + 6H_2O$

1. $2NaOH+H_2CO_3

ightarrow Na_2CO_3 + 2H_2O$

1. $KOH + HBr

ightarrow KBr+H_2O$

1. $H_2+O_2

ightarrow H_2O_2$

1. $4Na+O_2

ightarrow 2Na_2O$

1. $2Al(OH)_3+3H_2CO_3

ightarrow Al_2(CO_3)_3+6H_2O$

1. $16Al + 3S_8

ightarrow 8Al_2S_3$