A) balance the following equations:
i) pbcl2 + agno3 < > agcl + pb (no3) 2
ii) alcl3 + nh4oh < > al(oh)3 + nh4cl
iii) fecl3 + ca(oh)2 < > cacl2 + fe(oh)3
iv) pb(clo3)2 + k2so4 < > pbso4 + kclo3
v) na + hoh < > naoh + h2
vi) zn + hcl < > zncl2 + h2
vii) al + agch3coo < > al(ch3coo)3 + ag
viii) mgo + hno3 < > mg (no3)2 + h2o
ix) mno2 < > mn3o4 + o2
b) why is it incorrect to alter the chemical formula when balancing an equation?