A 400.0 ml flask is filled with a gas its formula weight is 70.9 grams/mole. The Density of the gas is 3.16 g/L.
Remember to report all your answer to the correct number of Significant figures
(a) What is the Mass of gas in the flask in grams? (Put answer in Decimal Notation form)
(b) What is the volume of gas in the flask in m%: (Put answer in Sci Notation form)
x10
m3
(C) How many molecules of the gas are in the flask (Put answer in Sci Notation form)
X10
molecules
G

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.