3. Another friend from chem class has a mother who is a chemist. Your friend's mother invites the class to
visit her lab and observe one of her experiments. In
her experiment, she super-cools a
pure sample of atoms to such a low
temperature (almost absolute zero)
that the atoms form a "super-atom"
where all of the particles exist in
the same energetic state at once!
What's really cool is when light
travels through this sample, it even
slows down! What is the sample's state?

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2