A solution contains 2.38 g of magnesium chloride, MgCl, in 500 cm3 of solution What is the concentration of
chloride ions in g/dm3?​​

3.54g Cl-/dm³

Explanation:

To solve this question we must, as first, find the mass of chloride ions finding first, the moles of MgCl2. Then, we must convert the cm³ to dm³ (1cm³ = 0.001dm³).

Moles MgCl2 -Molar mass: 95.211g/mol-

2.38g * (1mol / 95.211g) = 0.0250 moles MgCl2

Moles Cl-:

0.0250 moles MgCl2 * (2mol Cl- / 1mol MgCl2) = 0.0500 moles Cl-

Mass Cl- -Molar mass: 35.45g/mol-:

0.0500 moles Cl- * (35.45g / mol) = 1.77g of chloride ions

dm³:

500cm³ * (0.001dm³ / 1cm³) = 0.500dm³

The concentration is:

1.77g of chloride ions / 0.500dm³ =

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.