Chemistry final help ya'll

the question is in the picture

-20kJ/mol minus 66kj/mo

Explanation:

2NO2 = N2O4

Delta H 2NO2 = +66 kj/mol

Delta H N2O4 = -20kJ/mol

Change in entropy = Change in heat of a system

Delta H = Hfinal minus Hinital

So in our case it would be

-20kJ/mol minus 66kj/mol

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance

it means there are 3 atoms of oxygen