<span>d)S is not one of them.
Here's an easy way to remember them, attached: </span>
3 elements are present in HCOOH - hydrogen, oxygen, and carbon.
Mass of copper : 0.165 g
<h3>Further explanation</h3>
Given
5.0 A over 100 seconds
Required
Mass of copper
Solution
Faraday's law:
<em>The mass of the substance formed at each electrode is proportional to the electric current flowing in the electrolysis</em>
<em />
<em />
e = Ar / valence = eqivalent weight
i = current
t = time
W = weight
CuSO₄ ----> Cu²⁺ + SO₄²⁻
Cu ----> Cu²⁺ + 2e
e = Ar/2
= 63,5/2 = 31,75

I believe its B. <span>The chemical formula for water H2O represents 2 hydrogen and 1 oxygen in the compound. </span>
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