Answer: Region 3
Explanation: The temperature and time graph suggests that region 3 is the region in which the substance can co exist in both the phases that is solid phase and liquid phase.
Region 1 explains that the the solid has just started melting and there occurs a break point and then region 2 again explains that the solid is taking more time with temperature to get converted into the liquid and thus region 3 explains the equilibrium between the two phases.
Answer:
See Below.
Explanation:
Recall that molarity is defined by moles of solute over liters of solution (mol/L).
Therefore, to make 90.0 mL of 2.0 M MgSO₄, we will need:

Convert this amount to grams. The molecular weight of MgSO₄ is 120.38 g/mol:

Therefore, to make the solution, we can add 22 grams of MgSO₄ into a graduated cylinder, then mix and dilute the solution with distilled water until we reach 90.0 mL.
1.7 x 10 to the power of 22 formula units
A formula is the empirical formula of any ionic or covalent network solid compound used as an independent entity for stoichiometric calculations.