how do you balance these equations? a) Ca3(PO4)2 + SiO2 + C → CaSiO3 + P + CO b) N2H2 + NO2 → N2 + H2O please help!!!!?

I think you are asking "how", but are not only asking for the answers.


(a)
(1) Write the unbalanced equation :
_Ca3(PO4)2 + _SiO2 + _C → _CaSiO3 + _P + _CO

(2) Put "1" (not necessary to write) as the coefficient of Ca3(PO4)2 and "2" as that of P, and thus the numbers of "P" on both sides are equal to 2.
Ca3(PO4)2 + _SiO2 + _C → _CaSiO3 + 2P + _CO

(3) Put "3" as the coefficient of CaSiO3, and thus the numbers of "Ca" on both sides are equal to 3.
Ca3(PO4)2 + _SiO2 + _C → 3CaSiO3 + 2P + _CO

(4) Put "3" as the coefficient of SiO2, and thus the numbers of "Si" on both sides are equal to 3.
Ca3(PO4)2 + 3SiO2 + _C → 3CaSiO3 + 2P + _CO

(5) Put "5" as the coefficient of CO, and thus the numbers of "O" on both sides are equal to 14.
Ca3(PO4)2 + 3SiO2 + _C → 3CaSiO3 + 2P + 5CO

(6) Put "5" as the coefficient of C, and thus the numbers of "C" on both sides are equal to 5. The balanced equation is :
Ca3(PO4)2 + 3SiO2 + 5C → 3CaSiO3 + 2P + 5CO


(b)
(1) Write the unbalanced equation :
_N2H2 + _NO2 → _N2 + _H2O

(2) Put "1" (not necessary to write) as the coefficient of NO2 and "2" as that of H2O, and thus the numbers of "O" on both sides are equal to 2.
_N2H2 + NO2 → _N2 + 2H2O

(3) Put "2" as the coefficient of N2H2, and thus the numbers of "H" on both sides are equal to 4.
2N2H2 + NO2 → _N2 + 2H2O

(4) Put (5/2) as the coefficient of N2, and thus "N" on both sides are equal to 5.
2N2H2 + NO2 → (5/2)N2 + 2H2O

(5) Multiply the equation by "2" in order to avoid the appearance of fraction. The balanced equation is :
4N2H2 + 2NO2 → 5N2 + 4H2O

Ca3(PO4)2 + 3 SiO2 + 5C → 3 CaSiO3 + 2 P + 5 CO

4 N2H2 + 2 NO2→ 5 N2 + 4 H2O

Ca3(PO4)2 + 3SiO2 + 5C ---> 3CaSiO3 + 2P + 5CO
2N2H4 + 2NO2 ----> 3N2 + 4H2O