Achemist prepares a solution of fluoride (mgf2) by measuring out 0.0191 ųmol of magnesium fluoride into a 400. ml volumetric flask and filling the flask to the mark with water. calculate the concentration in mol/l of the chemist's magnesium fluoride solution.

The answer to your question is:  0.05 M

Explanation:

I'm not sure about the units umol, I think is units mol.

Data

MgF2 = 0.0191 mol

Volume = 400 ml

Molarity = moles / volume

Molarity = 0.0191 / 0.4 l

Molarity = 0.048 ≈ 0.05 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 correct answer to this question is 2