Calculate the number of Aluminium ions present in 1.5 gram of Aluminium oxide

1.771x10^22

Explanation:

6.02x10^23:avogadro's number

2: number of Al ions in Al2O3

1.5/102=0.0147:number of moles in the compound

moles=mass/relative mass number

so 0.0147x(6.02x10^23)x2=1.771x10^22

i think it is d. e because the next one is igneous.

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.