balancing chemical equation

The following equation is not balanced:                                             

K₃PO₄ + Ca(NO₃)₂ → Ca₃(PO₄)₂ + KNO₃                                                  

Which of the following choices expresses the equation after balancing                                                                                                        

• K₆P₂O₈ + Ca₃N₆O₁₈ → Ca₃P₂O₈ + K₆N₆O₁₈

• K₃PO₄ + Ca(NO₃)₂ → Ca₃(PO₄)₂ + 3KNO₃

• 2K₃PO₄ + Ca(NO₃)₂ → Ca₃(PO₄)₂ + 6KNO₃

• 2K₃PO₄ + 3Ca(NO₃)₂ → Ca₃(PO₄)₂ + 6KNO₃                                 

The following equation is not balanced:                                            

Mg₃N₂ + H₂SO₄ → MgSO₄ + (NH₄)₂SO₄                                                    

Which of the following choices represents the coefficient of H₂SO₄ after balancing

• 1

• 3

• 4

• 7

Which of the following equations achieve the law of mass conservation

• N₂  + 3H₂ → 2NH₃

• H₂ + Cl₂ → HCl

• 2H₂ + O₂ → H₂O

• Na₂ + Cl₂ → 2NaCl    

In the following equation:                                                                   

(X)P₄O₆ + 8H₂O + 2O₂ → (Y)H₂PO₃                                                   

What is the value of the coefficient (Y) if (X=2)

• 2

• 4

• 6

• 8

Sodium carbonate reacts with hydrochloric acid to produce sodium chloride, carbon dioxide and water. what is the correct order of the coefficients of these substance in the balanced chemical equation from left to right  

• 3 – 6 – 6 – 3 – 4

• 8 – 6 – 5  – 1 0 – 5

• 1 – 2 – 2 – 1 – 1

• 5 – 10 – 10 – 5 – 5

Heating pyrite ore (FeS₂) is represented by the following unbalanced equation                                                                                

FeS₂ + O₂  SO₂ + Fe₂O₃                                                                         

What are the coefficients of the reactants and products respectively                                                                                                      

• 4,2,8,7

• 2,4,7,8

• 2,11,7,8    

• 4,11,8,2

What is the coefficient of oxygen in the following equation after balancing

NH₃ + O₂ → NO₂ + H₂O                                                                             

• 1

• 3

• 4

• 7