3. how many atoms are found in 0.000256 moles?

1.54×10^20 atoms

Explanation:

It's done by using the relation

N=n×L where,

N = number of entities present

n= amount of substance (mole)

L= Avogadro's constant which is 6.02×10^23

now from the question, given

n=0.000256

And L=6.02×10^23

N= 0.000256×6.02×10^23

N= 1.54×10^20 atoms

the answer to your question is c.

if you read the house of usher you should know that the house was haunted

the product of the pressure and volume is also constant