0.448 moles of ions will form when a 42.66-gram sample of magnesium chloride is dissolved in water (option A).
<h3>How to calculate number of moles?</h3>
According to this question, when magnesium chloride (MgCl2) dissolves in water, it dissociates into magnesium ions and chloride ions as follows:
MgCl2(aq) ⟶ Mg2+(aq) + Cl−(aq)
However, if a 42.66-gram sample of magnesium chloride is dissolved in water, this means that 42.66g/molecular mass of MgCl2 will be the number of moles of the ionic products.
molecular mass of MgCl2 = 95.3g/mol
moles = 42.66g ÷ 95.3g/mol = 0.448mol
Therefore, 0.448 moles of ions will form when a 42.66-gram sample of magnesium chloride is dissolved in water.
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Acids are ionic compounds that break apart in water to form a hydrogen ion. The strength of an acid is based on the concentration of hydrogen ions in a solution. The more hydrogen ions, the stronger the acid. Bases are ionic compounds that break apart in water to form negatively charged hydroxide ions. The strength of the base is based on the concentration of hydroxide ions.
Hence, letter C is the correct answer.
Answer : The standard enthalpy of formation of ethylene is, 51.8 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 formation reaction of 
will be,
The intermediate balanced chemical reaction will be,
(1) 
(2) 
(3) 
Now we will reverse the reaction 1, multiply reaction 2 and 3 by 2 then adding all the equations, we get :
(1) 
(2) 
(3) 
The expression for enthalpy of formation of will be,
Therefore, the standard enthalpy of formation of ethylene is, 51.8 kJ/mole
Answer:
An ionic bond is an attraction between ions of opposite charge in an ionic compound.
The gas will obey Boyles Law:
P1 V1 = P2 V2 where P1 and V1 are the original pressure and volume and P2 and V2 are the new values.
If V2 = 2V1 (given) then:
P1 V1 = P2 *2 V1
P2 = P1 V1 / 2V1
P2 = P1 / 2
In other words the pressure is halved. (answer).
