Essential

Question 1

Electron affinity

Answer 1

Energy change that occurs when electron is added to gaseous atom/ ion

Question 2

Resonance

Answer 2

The availability of different arrangements of electrons in a molecule or ion

Question 3

Purpose of constant pressure calorimeter

Answer 3

Calculate the heat of change for a physical or chemical process at constant pressure

Question 4

Heat of combustion

Answer 4

Heat liberated for the combustion of 1 mile of substance in excess oxygen

Question 5

The standard heat of formation

Answer 5

Heat accompanying the formation of 1 mile of a pure substance from the required amounts of the elements at standard conditions

Question 6

Electronegativity

Answer 6

Ability of atom/ molecule to attract electrons to itself.
EN has a numerical measure based on scale of 0-4.
Fluorine is most electro negative element of 4.
Caesium (Cs) has lowers value of 0.7.
Difference in electronegativities of bonded atoms is used to determine POLARITY of bonds.
Greater difference= more POLAR