There is 118 elements<span> in the periodic table</span>
Since the beaker was heated we can asume that only magnesium cloride is left in the beaker, therfore the difference between the beaker with magnesium chloride and the empty beaker give the mass of magnisium chloride:
Considering the definition of molarity, the molar concentration is 0.294
.
Molarity reflects the concentration of a solution indicating the number of moles of solute that are dissolved in a given volume.
The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:

Molarity is expressed in units
.
In this case, you know:
- amount of moles of solute= 0.250 moles
- volume= 0.850 L
Replacing in the definition of molarity:

Solving:
molarity= 0.294 
Finally, the molar concentration is 0.294
.
Learn more about molarity with this example: brainly.com/question/15406534?referrer=searchResults