What volume will 454 grams (1 lb) of hydrogen occupy at 1.05 atm and 25 degrees celsius

supongo que te refieres al paralaje estelar (observable).

si es así, entonces se puede inferir que la estrella está a más de 200 parsecs.

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

the answer would be a

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.