Answer:
HF
Explanation:
This concept can be understood from the knowledge of Intermolecular forces of attraction.
Intermolecular bonds are Van der Waals forces which are weak forces of attraction joining non-polar and polar molecules together. They exist in the form of London Dispersion Forces and Dipole-dipole attraction.
An example of Dipole-dipole attraction is the hydrogen bond which is a unique dipole-dipole attraction between polar molecules in which a hydrogen atom is directly joined to a highly electronegative atom such as fluorine, oxygen, or nitrogen).
Molecules that possess the characteristics of hydrogen bonding have a higher boiling point. In the given question, only HF undergo hydrogen bond due to the electronegative effect of the fluorine element.
F2 occurs as a weak London dispersion force and it occurs between non-polar molecules.
1) Chemical equation
16Fe(s) + 3S8(s) ---> 8Fe2S3
2) Molar ratios:
16 mol Fe : 3 mole S8 : 8 mol Fe2S3
3) Convert masses in grams to number of moles
number of moles = mass in grams / molar mass
a) iron, Fe
mass = 3.0 g
atomic mass = 55.845 g/mol
=> number of moles of Fe = 3.0g / 55.845 g/mol = 0.0537 mol
b) Sulfur, S8
mass = 2.5 g
molar mass = 8*32.065 g/mol = 256.52 g/mol
=> number of moles of S8 = 2.5g / 256.52 g/mol = 0.009746 mol
4) Limiting reactant
Theoretical ratio actual ratio
16 mol Fe / 3 mol S8 0.0537 mol Fe / 0.009746 mol S8
5.33 5.50
So, there is a little bit more Fe than the theoretical needed to react all the S8, which means the S8 is the limiting reactant.
5) Calculate the number of moles of iron (III) produced with 2.5 g (0.009746 moles) of S8
3moles S8 / 8 moles Fe2S3 = 0.009746 moles S8 / x
=> x = 0.009746 * 8 / 3 moles Fe2S3 = 0.026 moles Fe2S3
6) Convert 0.026 moles Fe2S3 into grams
mass in grams = number of moles * molar mass
molar mass of Fe2S3 = 207.9 g/mol
mass = 0.026 mol * 207.9 g/mol = 5.40 g
7) Answer: option D)
Explanation:
question 44
the number 35 of bromine represents the atomic number
question 45
29 protons,
27 electrons
29-27 = +2
the charge on the following particle is
+2
Answer:
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