Formation of hydrates is considered to be a chemical change.
The reaction for the formation of MgO(s):
2 Mg (s) + O2(g) -à
2MgO(s) ΔH = -601.24
kJ/mol
<span>The enthalpy
information is taken from: http://webbook.nist.gov/cgi/inchi?ID=C1309484&Mask=2</span>
From the equation and with an enthalpy change of -231 kJ:
-231 kJ * 2 mol Mg * (1/-601.24 kJ/mol) = 0.76841 mol Mg
Then, with the molar mass of MgO = 40.3,
0.76841 mol Mg *(2 mol MgO/2 mol Mg)* 40.3 g/mol MgO = <span>30.967 g MgO</span>
Answer:
The correct option is;
A) The water molecules group together in clumps.
Explanation:
To answer the question, we look at each option as follows
A) The water molecules group together in clumps
This does not aid dissolution of compounds as clumping excludes non polar molecules, making them less soluble.
B) The partial negative oxygen atom end of the water molecule surround cations.
When an ionic compound such as NaCl is dissolved in water, the oxygen atoms surround the positive Na⁺ cations in the solution.
C) The partial positive hydrogen atom end of the water molecule surround anions
When the ionic NaCl compound is dissolved in water, the hydrogen atoms surround the negative Cl⁻ anions in the solution.
D) The water molecules also dissolve nonelectrolytes by creating a hydration sphere around the molecule.
Water is able to dissolve nonelectrolytes by creating an hydration sphere or hydration shell around the molecule.
Answer:

Explanation:
This reaction type is a single replacement. The format of a single replacement is:

A= Al
B= Ni
C= SO
The coefficient 3 for Ni would become a subscript for AC. After you plug those into the reaction you need to count how many of each are on the left side and try to get the same number on the right side. Both sides must be equal to have a balanced equation.