Answer : The value of 
for the reaction is +571.6 kJ/mole.
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The given chemical reaction is,
Now we have to determine the value of for the following reaction i.e,
According to the Hess’s law, if we reverse the reaction then the sign of change.
So, the value 
for the reaction will be:
Hence, the value of for the reaction is +571.6 kJ/mole.
This polarity makes water molecules attracted to each other. The oxygen-hydrogen bond in the alcohol molecule is also polar. But, the carbon hydrogen bonds in the rest of the alcohol molecule are nonpolar. In these bonds, the electrons are shared more or less evenly.
Answer:
Mg donates two electrons to O
Explanation:
Lewis dot notation uses dots and crosses to represent valence electrons on atoms.
Magnesium is a metal and would donate or lose electrons during bonding.
Oxygen is a non metal and would gain electrons during bonding.
The correct option is;
Mg donates two electrons to O
Surface tension is the result of water molecules pulling inward with a strong attractive force.
The attractive force brings the molecules on the surface of the water close together.
The attractive force causes the surface of the water to be drawn toward the water molecules beneath the surface. <span>
Since there are no water molecules above the surface, there are uneven forces. This causes surface tension, allowing the coin to float on the water’s surface.</span>
