Answer:
These elements show variable oxidation state because their valence electrons in two different sets of orbitals, that is (n-1)d and ns. The energy difference between these orbitals is very less, so both the energy levels can be used for bond formation.
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The answer should be (3) <span>They have different molecular structures and different properties.
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Answer:
-3.72 (or -3.70 depending on what values you used)
Explanation:
First, use the molar mass of Cl2 convert the mass of Cl2 to moles.
1.48 g Cl2(1 mol70.906 g)=0.02087 mol Cl2
Note that we are given ΔH=−886kJ. This refers to the enthalpy change associated with the reaction of 5mol of Cl2 by the balanced equation shown below.
2P+5Cl2⟶2PCl5ΔH=−886kJ
Therefore, to determine the enthalpy change associated with the reaction of 1.48gCl2, divide ΔH by 5molCl2 to determine the enthalpy change per mole of Cl2, then multiply by 0.02087 mol Cl2. (note: if you round up here to .021 mol of Cl2 you will get the final answer of -3.72 later)
0.02087 mol Cl2(−886 kJ5 mol Cl2)=−3.698 kJ
Rounding the answer should to three significant figures, we find that the enthalpy change associated with the reaction of 1.48gCl2 is −3.70 kJ.
Notice that coefficients in stoichiometric equations (indicating numbers of moles) are exact, so they do not constrain the number of significant figures.
Answer:
19.2g
Explanation:
The equation of the reaction is;
Li3N(s) +3H2O(l) ---->NH3(g) +3LiOH(aq)
From Avogadro's law we know that 1 mole of any gas occupies a volume of 22.4 L under standard conditions.
It is also clear from the equation that 1 mole of lithium nitride produces 1 mole of ammonia occupying 22.4L volume
Hence;
1 mole of Lithium nitride yields 22.4 L of ammonia
x moles of lithium nitride yields 12.26L of ammonia
x= 12.26×1/22.4
x= 0.55 moles of lithium nitride
Molar mass of lithium nitride= 34.83 g/mol
Mass of lithium nitride = number of moles × molar mass
Mass of lithium nitride= 0.55 moles × 34.83 g/mol
Mass of lithium nitride = 19.2g
The answer is (4). You may recall hearing about the "sea of electrons" model of metals. Metals represent the ultimate case of delocalized (shared) valence electrons, and these delocalized valence electrons are what freely move around, conducting current through the body of the metal.