Which equations are balanced? Select four options. Mg3N2 + H2O → 3MgO + 2NH3 C3H8 + 5O2 → 4H2O + 3CO2 Zn + 2HCl → ZnCl2 + H2 3Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 6H2O 3H2SO4 + 2Fe → Fe2(SO4)3 + H2 4Al + 3O2 → 2Al2O3

C3H8 + 5O2 → 4H2O + 3CO2

Zn + 2HCl → ZnCl2 + H2

3Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 6H2O

4Al + 3O2 → 2Al2O3

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

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements