You start by diving each quantity given by the atomic wight of each element:
Phosphorus (P) 
Hydrogen (H) 
Then you divide by the lowest number:
for phosphorus
for hydrogen
So the empirical formula will be:
The answer would be B) 10,000 DM is equal to 1 kilometer.
Answer:
The solutions should be added in this order NaCl > Na2SO4 > Na2S
Explanation:
Silver is insoluble as a chloride, so the silver ions get precipitated on addition of chloride ion as silver chloride. This means Ag+ would be removed the first.
So we will add NaCl in the first step.
The following reaction will occur.
Ag+ + Cl- → AgCl(s)
Both, Pb2 and Ni are soluble as chlorides. (lead chloride is soluble as a hot solution but will ppt when colder).
When we add Na2SO4, Pb2+ will get precipitated (because it's insoluble) as PbSO4 and Ni will remain soluble as NiSO4 is soluble in water.
The reaction that will occur is:
Pb^2+ + SO4^2- → PbSO4(s)
Nickel is insoluble as a sulfide. So when we will add Na2S, nickel will be precipitated as sulfide and be able to separate and be collected.
The solutions should be added in this order NaCl > Na2SO4 > Na2S
The percentage of the sulfur (S) in the compound CuSO₄ is 20.1 %.
<h3>What is the mass percentage?</h3>
The percentage of an element in a compound can be determined as the number of parts by mass of that element present in 100 parts by mass of the given compound.
First, calculate the molecular mass of the given compound by the addition of the atomic masses of all the present elements in the molecular formula. Then, the percentage of the elements can be determined by dividing the total mass of the element by the molar mass of the compound multiplied by 100.
Given, the atomic mass of copper, sulfur, and oxygen is 63.55 g, 32.07 g, and 16.0g respectively.
The molecular mass of CuSO₄ = 63.55 + 32.07 + 4(16.0) = 159.62 g
The mass percentage of the sulphur = (32.07/159.62) × 100 = 20.1 %
Therefore, the mass percentage of the sulfur is equal to 20.1 %.
Learn more about the mass percentage, here:
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