Answer:
<em>Nitrogen = 17.07%</em>
Explanation:
We are asked to calculate the percentage by mass of nitrogen in Ca(NO3)2.
The molar mass of calcium nitrate is 164,088 g/mol.
In this 164.088 g/mol there are 2 nitrogen atoms.
Molar mass of nitrogen = 14,0067 g/mol
% Nitrogen = molar mass of N/total molar mass of the compound
% Nitrogen =[(2 x 14.0067)/164.088]*100
% Nitrogen = 17.07%
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Physical, because the ice is only changing it's state. It's not changing to a new substance.
It can be a compound or a single element. An element is a pure substance that cannot be separated into simpler substances by chemical or physical means. There are about 117 elements, but carbon, hydrogen, nitrogen and oxygen are only a few that make up the largest portion of Earth.
hopefully that helps
Answer: 2 lone pairs, square planar
Explanation:
Using the VSEPR ( Valence Shell Electron Pair Repulsion)Theory
To calculate the number of lone pairs electron can be done using the formula;
Number of electrons = ½ (V+N-C+A)
V mean valency of the central atom
N means number of monovalent bonding atoms
C means charge on cation
A means charges on anion
Therefore, to calculate the number of lone pair electron C=A=0;
Number of electrons = ½ (8+4) = 12/2 = 6
Number of bonding pair = 4
Number of lone pairs of electron = 6-4 = 2
The hybridrization of the compound is sp3d2 because the number of electrons around the central atom is 6.
The geometry of the compound is square planar and this is because of the repulsion between the bonding pair of electrons and lone pair of electrons which causes the lone pair of electrons to lie in a perpendicular plane in order to acquire stability.
Explanation:
Equation of the reaction:
Br2(l) + Cl2(g) --> 2BrCl(g)
The enthalpy change for this reaction will be equal to twice the standard enthalpy change of formation for bromine monochloride, BrCl.
The standard enthalpy change of formation for a compound,
ΔH°f, is the change in enthalpy when one mole of that compound is formed from its constituent elements in their standard state at a pressure of 1 atm.
This means that the standard enthalpy change of formation will correspond to the change in enthalpy associated with this reaction
1/2Br2(g) + 1/2Cl2(g) → BrCl(g)
Here, ΔH°rxn = ΔH°f
This means that the enthalpy change for this reaction will be twice the value of ΔH°f = 2 moles BrCl
Using Hess' law,
ΔH°f = total energy of reactant - total energy of product
= (1/2 * (+112) + 1/2 * (+121)) - 14.7
= 101.8 kJ/mol
ΔH°rxn = 101.8 kJ/mol.
