The element name is: Antimony
The chemical symbol: Sb
Atomic Mass: 121.75
Atomic Number: 51
<u>Answer:</u> The particle released in the given reaction is one alpha particle
<u>Explanation:</u>
In a nuclear reaction, the total mass and total atomic number remains the same.
For the given fission reaction:

Total mass on reactant side = total mass on product side
222 = A + 218
A = 4
Total atomic number on reactant side = total atomic number on product side
86 = Z + 84
Z = 2
The isotopic symbol of unknown element is
. Another name of helium atom is alpha particle.
Hence, the particle released in the given reaction is one alpha particle
<u>Answer:</u> The given amount of iron reacts with 9.0 moles of
and produce 6.0 moles of 
<u>Explanation:</u>
We are given:
Moles of iron = 12.0 moles
The chemical equation for the rusting of iron follows:

By Stoichiometry of the reaction:
4 moles of iron reacts with 3 moles of oxygen gas
So, 12.0 moles of iron will react with =
of oxygen gas
- <u>For iron (III) oxide:</u>
By Stoichiometry of the reaction:
4 moles of iron produces 2 moles of iron (III) oxide
So, 12.0 moles of iron will produce =
of iron (III) oxide
Hence, the given amount of iron reacts with 9.0 moles of
and produce 6.0 moles of 
Answer: 75%
Explanation:
The following information can be gotten from the question:
Waste = 70kg
Theoretical yield = 280kg
Therefore, the actual yield will be the difference between the theoretical yield and the waste which will be:
= 280kg - 70kg = 210kg
The percent yield will now be:
= Actual yield / Theoretical yield × 100
= 210/280 × 100
= 3/4 × 100
= 75%