What polyatomic ion forms a neutral compound when combined with a group 2a monatomic ion in a 1: 1 ratio?
• ammonium
• carbonate
• nitrate
• phosphate

Cabonate

Explanation:

Hi, this are the ions you listed:

Ammonium:

Carbonate:

Nitrate:

Phosphate:

All group 2A compounds (like Ca, Mg) have a valence number of +2. So:

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.

it would be d. henry moseley

hope this !

and sorry if i'm late. have a good rest of your day! : d