Can heat of reaction change with phase?

[stester77s]

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For example, arsenic is very reactive as a gas, but less reactive as a solid (if this is incorrect, please correct me). This means it's less stable, and has higher energy.

So is it correct to say that when equal amounts of solid and gas arensic react with oxygen to produce the same compound (As4O6), that the gas reaction will produce more heat, since the gas is less stable.

I thought that since their the same compound (just in different phases, solid vs gas), that it would produce the same amount of heat. But apparently this is incorrect. Please explain further.

Here is the question:

1. If equal masses of gray arsenic and yellow arsenic are allowed to completely react with oxygen at 298 K and constant pressure to form As4O6, which would produce more heat and why?
   
   1. The yellow, because it is less stable than the gray.
      
      
   2. The gray, because it is more stable than the yel low.
      
      
   3. Both would produce the same amount of heat because they form the same product.
      
      
   4. Both would produce the same amount of heat because they are the same element.
      

 

[chenzt]

Think... How do you get anything to go from solid to gas?

 

[SweetBurger]

May I ask is the answer to the question number 1?

 

[funtertaining15]

,...yeah, what's the answer? plus, are yellow as grey As solids? DO they go into more depth or is that just the question?

 

[ipmed]

Yellow. Because h= product - reactant and product release energy whereas reactant absorb energy and take away from the energy release