Hydrogen has two naturally occurring isotopes, 1h and 2h. chlorine also has two naturally occurring isotopes, 35cl and 37cl. thus, hydrogen chloride gas consists of four distinct types of molecules: 1h35cl, 1h37cl, 2h35cl, and 2h37cl. place these four molecules in order of decreasing rate of effusion.

Molecules in order of decreasing rate of effusion:

Explanation:

Mass of gas=

Mass of gas =

Mass of gas =

Mass of gas =

According Graham's law:

'The rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas'.The equation given by this law follows the equation:

So, higher the molecular mass of the gas lower will be the effusion rate and vice versa.

Increasing order of molecular masses of the given gases:

Decreasing order of effusion rate respective to gases:

Molecules in order of decreasing rate of effusion:

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.

if you're asking what comes out, it's steam.