Question

emerging level - check each chemical equation below and indicate if it is balanced or not. 1. cl₂ + 2nabr → 2nacl + br₂ balanced: yes no 2. 3na + o₂ → 2na₂o balanced: yes no 3. h₂ + o₂ → h₂o balanced: yes no 4. 2al₂o₃ → 4al + 3o₂ balanced: yes no 5. p₄ + 5o₂ → p₄o₁₀ balanced: yes no 6. 2p + 6o₂ → 2p₂o₅ balanced: yes no 7. mg + 2hcl → h₂ + mgcl₂ balanced: yes no 8. 2na + cl₂ → 2nacl balanced: yes no 9. 2nacl + f₂ → 2naf + cl₂ balanced: yes no 10. 2hgo + cl₂ → 2hgcl + o₂ balanced: yes no 1. mg + o₂ → 3mgo 2. cucl₂ + h₂s → cus + hcl

Explanation:

Step1: Recall law of conservation of mass

In a balanced chemical equation, the number of atoms of each element on the reactant side must equal the number of atoms of the same element on the product side.

Step2: Analyze equation 1: $Cl_2 + 2NaBr

ightarrow 2NaCl+Br_2$
On the reactant side, we have 2 Cl - atoms, 2 Na - atoms and 2 Br - atoms. On the product side, we have 2 Na - atoms, 2 Cl - atoms and 2 Br - atoms. So it is balanced.

Step3: Analyze equation 2: $3Na+O_2

ightarrow 2Na_2O$
On the reactant side, we have 3 Na - atoms and 2 O - atoms. On the product side, we have 4 Na - atoms and 1 O - atom. It is not balanced.

Step4: Analyze equation 3: $H_2 + O_2

ightarrow H_2O$
On the reactant side, we have 2 H - atoms and 2 O - atoms. On the product side, we have 2 H - atoms and 1 O - atom. It is not balanced.

Step5: Analyze equation 4: $2Al_2O_3

ightarrow 4Al + 3O_2$
On the reactant side, we have 4 Al - atoms and 6 O - atoms. On the product side, we have 4 Al - atoms and 6 O - atoms. So it is balanced.

Step6: Analyze equation 5: $P_4+5O_2

ightarrow P_4O_{10}$
On the reactant side, we have 4 P - atoms and 10 O - atoms. On the product side, we have 4 P - atoms and 10 O - atoms. So it is balanced.

Step7: Analyze equation 6: $2P + 6O_2

ightarrow 2P_2O_5$
On the reactant side, we have 2 P - atoms and 12 O - atoms. On the product side, we have 4 P - atoms and 10 O - atoms. It is not balanced.

Step8: Analyze equation 7: $Mg+2HCl

ightarrow H_2+MgCl_2$
On the reactant side, we have 1 Mg - atom, 2 H - atoms and 2 Cl - atoms. On the product side, we have 2 H - atoms, 1 Mg - atom and 2 Cl - atoms. So it is balanced.

Step9: Analyze equation 8: $2Na+Cl_2

ightarrow 2NaCl$
On the reactant side, we have 2 Na - atoms and 2 Cl - atoms. On the product side, we have 2 Na - atoms and 2 Cl - atoms. So it is balanced.

Step10: Analyze equation 9: $2NaCl + F_2

ightarrow 2NaF+Cl_2$
On the reactant side, we have 2 Na - atoms, 2 Cl - atoms and 2 F - atoms. On the product side, we have 2 Na - atoms, 2 F - atoms and 2 Cl - atoms. So it is balanced.

Step11: Analyze equation 10: $2HgO+Cl_2

ightarrow 2HgCl + O_2$
On the reactant side, we have 2 Hg - atoms, 2 O - atoms and 2 Cl - atoms. On the product side, we have 2 Hg - atoms, 2 Cl - atoms and 2 O - atoms. So it is balanced.

Step12: Analyze equation 13: $Mg + O_2

ightarrow MgO$
On the reactant side, we have 1 Mg - atom and 2 O - atoms. On the product side, we have 1 Mg - atom and 1 O - atom. It is not balanced.

Step13: Analyze equation 14: $CuCl_2+H_2S

ightarrow CuS + HCl$
On the reactant side, we have 1 Cu - atom, 2 Cl - atoms, 2 H - atoms and 1 S - atom. On the product side, we have 1 Cu - atom, 1 S - atom, 1 H - atom and 1 Cl - atom. It is not balanced.

Answer:

1. Yes
2. No
3. No
4. Yes
5. Yes
6. No
7. Yes
8. Yes
9. Yes
10. Yes
11. No
12. No