b. Polar covalent bonds. The polar N-H bonds hold the NH3 molecules together. They are <em>intramolecular forces</em> of attraction <em>within a molecule</em>.
All the other options are <em>wrong</em>. They are <em>intermolecular forces</em> — the attractive forces <em>between different molecules</em>.
Answer:
The pressure will be doubled.
I think the correct word to fill in the blank would be carbon. Organic compounds are composed of carbon and at least one hydrogen atom. It is basically any compound that would contain carbon and covalently bonded to other elements or atoms usually these are hydrogen, nitrogen and oxygen. All living things are based on these compounds. These are the building blocks of organic chemistry. These compounds can be seen anywhere in Earth. May it be animals, plants, the soil, sugar, microorganisms and even in humans. Examples of these compounds are methanol, DNA, glucose, hexane, acetic acid, butane and the like.
Mass of Fe₂O₃ : 74.26 g
Volume of O₂ at STP = 15.624 L
<h3>Further explanation</h3>
Reaction
4Fe (s) + 3O₂ (g) ==> 2Fe₂O₃ (s)
mol Fe :
Ar Fe = 56 g/mol

mol Fe₂O₃ :

mass Fe₂O₃ :
MW Fe₂O₃ : 159,69 g/mol

mol O₂ :

volume O₂ at STP(1 mol=22.4 L)

(4) covalent is your answer.