In an experiment, seth was given a substance known as ammonium carbonate, (nh4)2co3. seth connected a bunsen burner to the gas valve using a gas hose. he turned on the gas valve and lit the bunsen burner. using a test tube, seth heated a piece of ammonium carbonate. seth noticed the following:
- condensation appeared on the sides at the top of the test tube.
- an ammonia smell was coming from the test tube.
seth continued to light a wooden splint and stick it down the test tube and it immediately was extinguished.

throughout this experiment, how many signs of chemical changes were observed and actual chemical changes took place?
a) 4
b) 5
c) 6
d) 7