Occupational Safety and Health Administration's (OSHA's) permissible exposure limit (PEL) for acetic anhydride is 5 ppm in air and the immediate danger to life and health (IDLH) value is 200 ppm in air. Such vapor concentrations can be determined by dividing the vapor pressure by 760 mmHg and then multiplying by 106 (VP/760 x 106). Calculate the vapor concentration at 20 ∘C and 50 ∘C.

At    

At    

Explanation:

From the question we are told that

 The permissible exposure limit (PEL) for acetic anhydride is  

  The  exposure that is of immediate danger to life and health

Gnerally the vapor  pressure of acetic anhydride at is  

Now converting to ppm from the description in the question

Gnerally the vapor  pressure of acetic anhydride at is    

Now converting to ppm from the description in the question

Note this vapor pressure are constant values

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 number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.