Determining the Empirical Formula of a Tin Oxide

Question

anonymous · Answer

In a lab tin and nitric acid was heated over a Bunsen burner. 

My results:
Weight of evaporating dish: 24.35g
Weight of dish with tin: 26.47g
Weight of dish with tin and nitric acid (before heating): 30.97g
Weight of dish with tin and acid (after heating): 27.03

anonymous · Answer

The question is: What are two things that you observed when you heated the mixture of tin and nitric acid over the Bunsen burner in the virtual lab, and why was it necessary to heat the mixture in order to determine the empirical formula?

And i dont understand...

anonymous · Answer

Not sure if I can help, but... What did you observe in the virtual lab?