It is either the 3rd answer or the 4th answer. Both are correct ways to write hydrates, but I was taught the 4th way. Just make sure this answer matches the format of the examples your teacher gave you.
Explanation:
Given parameters:
Mass of sample = 235g
Molecular mass of sample = 128.1g
Empirical formula = CH₂O
Unknown:
Mass of each element in the sample = ?
Solution:
To solve this problem, we must know that the empirical formula of any compound is the simplest ratio of the atoms it contains. This is not the true formula of the compound.
Molecular formula = (Empirical formula)ₙ
Let us find the molecular mass of the sample;
CH₂O = 12 + 2(1) + 16 = 30g
128.1 = (30)n
n = 4
The molecular formula of the compound is; (CH₂O)₄ = C₄H₈O₄
Now to find the grams of each element in the sample;
Express the molecular mass of each element and that of the compound as a fraction and multiply with the given mass;
For C;
= 88.06g
H;
= 14.68g
O:
= 117.41g
learn more:
Mass composition brainly.com/question/3018544
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Answer:
moles
Explanation:
We are given:
Moles of electron = 1 mole
According to mole concept:
1 mole of an atom contains
number of particles.
We know that:
Charge on 1 electron =
Charge on 1 mole of electrons =
The metal being plated has a +4 charge, thus the equation will be:

of electricity deposits = 1 mole of metal
Thus 861.8 C of electricity deposits =
moles of metal
Thus
moles of metal should be plated