Answer:
13
Explanation:
proton plus neutron equal to atomic mass
The empirical formula for pyrite is FeS2.
HOW TO CALCULATE EMPIRICAL FORMULA:
- The empirical formula represents the simplest whole number ratio of constituents element of a compound. The empirical formula of pyrite can be calculated as follows:
46.5 mass % Fe = 46.5g of Fe
53.5 mass % S = 53.5g of S
- Next, we divide each element's mass value by its molar mass
Fe = 46.5g ÷ 56g/mol = 0.83mol
S = 53.5g ÷ 32g/mol = 1.67mol
- Next, we divide each mole value by the smallest (0.83mol)
Fe = 0.83mol ÷ 0.83 = 1
S = 1.67mol ÷ 0.83 = 2.014
Approximately, the ratio of Fe to S is 1:2. Therefore, the empirical formula of pyrite is FeS2.
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The third option because the elements mentioned in that selection are in the same group, they must have similar properties.
Answer: D) protons.
The other option that would make the most sense would be electrons, however the mass of an electron is so small that is basically negligible, so it's not included in the atomic mass.
A single sodium ion will combine due to its charge on it
Na^+
The single sodium ion has total one positive charge on it. so it requires only one electron or can bond to one negative charge
in the given polyatomic anions
a) CO3^-2 : it has two negative charge. So it will react with two sodium ions
it will forms Na2CO3
b) PO4^-3 :it has three negative charge. So it will react with three sodium ions
it will forms Na3PO4
c) SO4^-2 : it has two negative charge. So it will react with two sodium ions
it will forms Na2SO4
d) NO3^-1: it has one negative charge. So it will react with one sodium ion
it will forms NaNO3
Hence the correct answer is
Nitrate ion will react with single sodium ion as
Na+ + NO3- ---> NaNO3
