Calculate the enthalpy for the following reaction. During the reaction, the temperature changes from 42.5 C to 37 C. The specific heat of HCl is 4.04J/g*C. Is the reaction endothermic or exothermic?

Kj/mol

Its an endothermic reaction

Explanation:

Enthalpy can be evaluated by using following formula -

where

q is the enthalpy or change in internal energy

m is the mass in kg

c is the specific heat

and is the change in temperature

Mass of HCl is equal to g/mol

or

Mass of HCl is equal to  Kg/mol

Substituting the given values in above equation, we get-

Kj/mol

Enthalpy is positive thus it is an endothermic reaction

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

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be