These mystery elements are at the top of their families on the periodic table. An element that is in the same family as element is likely to have which properties? A) Two valence electrons, solid, metal

B) Six valence electrons, gas, nonmetal

C) Six valence electrons, solid, nonmetal

D) Two valence electrons, solid, nonmetal

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.

1.solid

2.carbon dioxide

3.helium

no, the red giant is the hottest with 2.00.000.000 degrees celsius. while the white dwarf only 25,000 degrees celsius.

metric time was an attempt to create a standard unit of time based off of 10, but it never took off an is not included in the metric system (si)