Answer : The mass of 7.0 m chain is, 15.12 kg
Explanation :
As we are given that,
The weight of the chain per unit length = 2.16 kg/m
Now we have to determine the mass of chain for 7.0 m length.
As, the mass of 1 m length of chain = 2.16 kg
So, the mass of 7.0 m length of chain = 
= 15.12 kg
Therefore, the mass of 7.0 m chain is, 15.12 kg
The number of moles of NaOh that are contained in 65ml of 2.20M solution NaOh in H2o is calculated using the below formula
moles = molarity x volume /1000
that is 65 x2.20 /1000= 0.143 moles
Given problem:
S₂O₈²⁻
Find the oxidation number of S;
Oxidation number presents the extent of oxidation of each atom of elements a molecular formular or formula unit or an ionic radical.
For radicals:
"the algebraic sum of all the oxidation numbers of all atoms in an ion containing more than one kind of atom is equal to the charge on the ion "
S₂O₈²⁻; oxidation number of O is usually -2
2(S) + 8(-2) = -2
2S - 16 = -2
2S = -2 + 16
2S = 14
S = +7
The oxidation state of S in the radical is +7
No, it is not a scientific claim. If a ghost hunter catches a voice on video like ghost hunters do you can either believe it or not. Ghosts are more of a i believe it you dont have to type of thing becasue they have not been scientifically proven to exist.
Ionic bond is formed due to the transfer of electrons from one atom to another so that all atoms involved in the bond would become stable (with 8 electrons in the outermost level)
Now, for bromine, it has 35 electrons. This means that bromine has 7 valence electrons in the outermost level. Therefore, bromine needs to gain one electron in order to become stable.
Bromine can react with elements from:
group 1: each element in group 1 needs to lose one electron to become stable. Therefore, one bromine atom can form an ionic bond when combined with an atom of an element from group 1 (element in group 1 loses its electron for bromine atom).
group 2: each element in group 2 needs to lose two electrons to become stable. Therefore, two bromine atoms can form ionic bonds when combined with an atom of an element from group 2 (element in group 2 loses two electrons, one for each bromine atom).
group 3: each element in group 3 needs to lose three electrons to become stable. Therefore, three bromine atoms can form ionic bonds when combined with an atom of an element from group 1 (element in group 3 loses three electrons, one for each bromine atom).
Since no choices are given , I cannot tell the exact choice. But the correct one would be the element from either group 1 , 2 or 3.