Use the observations about each chemical reaction in the table below to decide the sign (positive or negative) of the reaction enthalpy AH and reaction entropy AS.
Note: if you have not been given enough information to decide a sign, select the "unknown" option.

Use the observations about each chemical reaction in the table below to decide the sign (positive or negative) of the reaction enthalpy AH and reaction entropy AS. Note: if you have not been given enough information to decide a sign, select the "unknown" option observations conclusions reaction ΔΗ is (pick one) The reverse of this reaction is always spontaneous. A As is (pick one) This reaction is spontaneous except below ΔΗ is (pick one) 38. °C but proceeds at a faster rate above (pick one) 91. °C As is ΔΗ iS (pick one) Crystallization of a pure compound is C spontaneous only below 146. °C. AS is (pick one) X

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

a) the particles of the chair are strongly held together.