How did Wegener explain the fact that Lystrosaurus fossils, an ancient land reptile, showed up on different continents? The continents were at one time joined together.

The fossils were moved by humans.

The Lystrosaurus swam between the two continents.

The fossils must be of different species.

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.

10 years is the answer

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.