Answer:
Explanation:
We will need a balanced chemical equation with masses, moles, and molar masses.
1. Gather all the information in one place:
M_r: 2.016 17.03
3H₂ + N₂ ⟶ 2NH₃
m/g: 6.33 × 10⁻⁴
2. Calculate the moles of H₂
3. Calculate the moles of NH₃
The molar ratio is 2 mol NH₃/3 mol H₂.
4. Calculate the molecules of NH₃
There are 6.022 × 10²³ molecules of NH₃/1 mol NH₃.
From the periodic table:
mass of oxygen = 16 grams
mass of carbon = 12 grams
mass of iron = 55.84 grams
Therefore:
molar mass of Fe3O4 = 3(55.84) + 4(16) = 231.52 grams
number of moles = mass/molar mass
number of moles of Fe3O4 = 23 / 231.52 = 0.099 moles
The balanced chemical equation that describes this reaction is:
<span>Fe3O4 + 2C --------> 2CO2 + 3Fe
From the balanced reaction above, we can note that:
one mole of Fe3O4 requires two moles of carbon to react with.
Therefore, to know the number of carbon moles required to react with 0.099 moles of Fe3O4, all you have to do is cross multiplication as follows:
number of carbon moles = (2*0.099) / 1 = 0.198 moles
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Answer: Thus 3 half lives have taken place.
Explanation:
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
Number of half lives =
Thus 3 half lives have taken place.