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