1. D. 5
2. B. 2
3. A. fluroine
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Answer:

Explanation:
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In this case, when balancing chemical reactions, we must make sure that the atoms of each element are the same at both reactants and products; thus, for the given reaction, we need two iron and aluminum atoms at each side based on their subscripts in the given oxides as shown below:

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Answer:
2 L is the new volume
Explanation:
We can apply the Ideal Gases Law to solve the problem.
At STP, we kwow that 1 mol of gas occupy a volume of 22.4 L
Then, how many moles do we have in 1 L?
Let's do it by a rule of three:
(1L . 1 mol) / 22.4L = 0.0446 moles
These moles are at 1 atm and 273 K of temperature, so let's change our conditions.
P . V = n . R .T
1 atm . V = 0.0446 mol . 0.082 L.atm/mol K . 546 K
V = 2 L
If we pay attention, we can notice that, if we double temperature, we double the volume.
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