Hey there!:
5 SiO2 + 2 CaC2 = 5 Si + 2 CaO + 4 CO2
Balancing a chemical equation is to equalize the quantity of atoms of the elements present in the reagents with the quantity of these same atoms of the elements present in the products.
Reagents: Products :
Si = 5*1 = 5 Si = 5 * 1 = 5
O = 5 * 2 = 10 Ca = 2 * 1 = 2
Ca = 2 * 1 = 2 O = 2 * 1 = 2
C = 2 * 2 = 4 C = 4*1 = 4
O = 4 * 2 = 8
Reagents = 5 + 10 + 2 + 4 = 21
Produts = 5 + 2 + 2 + 4 + 8 = 21
Hope that helps!