Answer:
C3H8 + 5O2 → 4H2O + 3CO2
Zn + 2HCl → ZnCl2 + H2
3Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 6H2O
4Al + 3O2 → 2Al2O3
Step-by-step explanation:
Balanced equations are where the number of elements of on one side equal the other side.
For eg, Na + Cl ---> NaCl (this is balanced because there's 1 Na in reactant and 1 in product, and same case for chlorine)
H2 + O2 ----> H2O (This is not balanced because there's two oxygen on reactant and only one on product so we multiply h2o by two and H2 by 2)
2H2+ O2 ---> 2H2O (now we have 4 hydrogen 2 oxygen in both reactant and product side)
From the options you gave apply this idea of Balanced equations are where the number of elements of on one side equal the other side.
You'll get the following as balanced:
C3H8 + 5O2 → 4H2O + 3CO2
Zn + 2HCl → ZnCl2 + H2
3Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 6H2O
4Al + 3O2 → 2Al2O3