You have to use Avogadro's number (6.02x10^23 molecules/mole) to find the number of moles each reactant starts off with.
moles of Fe and O₂:
12 atoms/(6.02x10^23 atoms/mole)=1.99x10^-23 mol Fe
6 molecules/(6.02x10^23 molecules/mole)=9.967x10^-24 mol <span>O₂
</span>Then you find the limiting reagent by finding how much product each given amount of reactant can make. Which ever one produces the least amount of product is the limiting reagent.
amount of Fe₂O₃ produced:
<span>(1.99x10^-23 mol Fe)x(2mol/4mol)= 9.967x10^-24mol Fe</span>₂O₃<span>
</span>(9.967x10^-24 mol O₂)x(2mol/3mol)= 6.645x10^-24 mol Fe₂O₃<span>
</span>since oxygen produces the leas amount of product, oxygen is the limiting reagent. since we know that oxygen is the limiting reagent we can use the amount of product formed with oxygen to find the amount of iron used.
6.645x10^-24 mol Fe₂O₃x(4mol/2mol)=1.329x10^-23 mol Fe consumed
<span> find the amount left over by subtracting the original amount of Fe by the amount consumed in the reaction.
</span>1.993x10^-23-1.329x10^-23= 6.645x10^-23mol Fe left
find the number of atoms by multiplying that by Avogadro's number.
<span>(6.645x10^-23mol)x(6.02x10^23 atoms/mol)=4 atoms
</span>therefore 4 atoms of Fe will be left over after the reaction happens.
I hope this helps.
the largest is francium, Z=87 , or caesium, Z=55 ; and the smallest is definitely helium, Z=2 .
Explanation:
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The specific gravity or relative density of a substance is the ratio of its density to the density of a reference material. The relative density of the concentrated salt solution is 1.044.
Mathematically;
Density of the concentrated salt = mass of salt/volume of salt = 5.222 g/5.000 mL = 1.044 g/mL
In the case of specific gravity, the reference material is always water and water has a density of 1 g/mL.
Hence, specific gravity of the concentrated salt solution =
Density of concentrated salt solution/density of equal volume of water
= 1.044 g/mL/1 g/mL
= 1.044
Note that specific gravity is dimensionless.
Learn more: brainly.com/question/9638888
Answer:
cream - contains a higher proportion of oil than water
ointment - dr4g mixed in approximately equal proportions of oil and water
i don't know about the other two sorry
