posted by ABCD .
Consider the following equations. For each, decide whether it represents a chemical reaction or a physical change.
a. SnCl4(aq) + 4H2O(l) Sn(OH)4(s) + 4HCl(aq)
b. 4K(s) + O2(g) 2K2O(s)
c. NaCl(s) Na+(aq) + Cl-(aq)
If the products are different from the reactants you have a chemical change; otherwise it's a physical change.