Answer:
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Explanation:
Symbiology of nuclear isotopes can be written in one of two ways. That is, for the symbiology Ni-63, the '63' represents the nuclear isotopic mass and represents the sum of the number of neutrons and protons. When expressed in subscript and superscript notation Ni-63 becomes ₂₈Ni⁶³ where '28' is the atomic number and represents the number of protons (p⁺) in the nucleus and the number '63', as mentioned above, represents the number of neutrons and protons. Thus, for any isotope the number of protons can NOT change or the element changes but the number of neutrons can change giving the various isotopes of a given element. Example: Oxygen exists in 3 primary isotopes, O-16, O-17 & O-18. Since the atomic number of oxygen is always 8 (i.e., 8 protons), writing it into the symbiology is optional => ₈O¹⁶, ₈O¹⁷ & ₈O¹⁸. However, the number of neutrons can change and is always listed in the symbiology by X-(mass no.) or ₐXᵇ, where a = # of protons (atomic no.) and b = #protons + #neutrons.
For determining the numbers of protons and neutrons, remember the large number is always a superscript (p⁺ + n°) and the smaller number always the subscript (p⁺). So, number of neutrons, therefore, can be easily be determined by 'superscript - subscript' = (p⁺ + n°) - (p⁺) = number of n°.
For nuclear equations, the mass and charge must balance for reactants and products. That is, ∑reactant superscripts = ∑product superscripts and ∑reactant subscripts = ∑product subscripts.
Given Ni-63 as decaying by β⁻ emissions (high energy electrons => ₋₁e°), one writes ...
₂₈Ni⁶³ => ₐXᵇ + ₋₁e° => ₂₈Ni⁶³ => ₂₉Cu⁶³ + ₋₁e°
Note: ∑reactant superscripts (63) = ∑product superscripts (63 + 0) and ∑reactant subscripts (28) = ∑product subscripts [(29 + (-1)].
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In an ionic compound the atoms are linked via ionic bonds. These are formed by the transfer of electrons from one atom to the other. The atom that loses electrons gains a positive charge whereas the atom that accepts electrons gains a negative. This happens in accordance with the octet rule wherein each atom is surrounded by 8 electrons
In the given example:
The valence electron configuration of Iodine (I) = 5s²5p⁵
It needs only one electron to complete its octet.
In the given options:
K = 4s¹
C = 2s²2p²
Cl = 3s²3p⁵
P = 3s²3p³
Thus K can donate its valence electron to Iodine. As a result K, will gain a stable noble gas configuration of argon while iodine would gain an octet. This would also balance the charges as K⁺I⁻ creating a neutral molecule.
Ans: Potassium (K)
Atoms combine as the electrons from each atom are attracted to the nuclei of the atoms. The results in bonds ranging from 100%covalent to bonds with higher character. The combination of atoms to form compounds occurs when the compounds being formed are at lower energy than the original atoms. In chemical change, the molecules in the reactants interact to form new substances.
Mass of methane takne = 1.5g
moles of methane used = masss / molar mass = 1.5 / 16 = 0.094 moles
mass of water = 1000 g
Initial temperature of water = 25 C
final temperature = 37 C
specific heat of water = 4.184 J /g C
1) Heat absorbed by water = q =m• C• ΔT = 1000 X 4.184 x (37-25) = 50208 Joules
2) Heat absorbed by calorimeter = Heat capacity X ΔT = 695 X (37-25) = 8340 J
3) Total heat of combustion = heat absorbed by water + calorimeter = 50208 + 8340 = 58548 Joules
This heat is released by 0.094 moles of methane
So heat released by one mole of methane =
- 622851.06 Joules = 622.85 kJ / mole
4) standard enthalpy of combustion = -882 kJ / mole
Error = (882-622.85) X 100 / 882 = 24.84 %