Can someone plz tell me the answer/ and explain how to get the answer

Awhite powder is added to a solution. the images show observations made before the powder is added, just after the powder has been added, and a little while later. (the liquid in the small beaker is phenol red solution.) what evidence shows that a chemical change has taken place?

Write the balanced chemical reaction for the formation of fe2(so4)3 from fe2o3 and so3 and determine how many moles of fe2(so4)3 are formed when 12.7 mol of so3 are reacted.

Solve this problem using the appropriate law. (remember that ) what is the pressure of 1.9 mols of nitrogen gas in a 9.45 l tank and at a temperature of 228 k?