A 54.0 mL aliquot of a 1.60 M solution is diluted to a total volume of 218 mL. A 109 mL portion of that solution is diluted by adding 161 mL of water. What is the final concentration? Assume the volumes are additive g

The final concentration is 0.16 M.

Explanation:

According to the dilution law:

where,

= molarity of stock solution = 1.60 M

= volume of stock  solution = 54.0 ml

= molarity of diluted solution = ?

= volume of diluted solution = 218 ml

Putting these values:

Now 109 ml of this diluted solution is further diluted by adding 161 mL of water.

Again applying dilution law:

Thus the final concentration is 0.16 M

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.

the answer would be a