Answer:
-1815.4 kJ/mol
Explanation:
Starting with standard enthalpies of formation you can calculate the standard enthalpy for the reaction doing this simple calculation:
∑ n *ΔH formation (products) - ∑ n *ΔH formation (reagents)
This is possible because enthalpy is state function meaning it only deppends on the initial and final state of the system (That's why is also possible to "mix" reactions with Hess Law to determine the enthalpy of a new reaction). Also the enthalpy of formation is the heat required to form the compound from pure elements, then products are just atoms of reagents organized in a different form.
In this case:
ΔH rxn = [(2 * -1675.7) - (3 * -520.0)] kJ/mol = -1815.4 kJ/mol
Answer:
9.88
Explanation:
As higher is the Ksp, more soluble is the compound. So, Co(OH)₂ is the less soluble hydroxide.
The maximum concentration of it must be 1x10⁻⁶ M, and the reaction is:
Co(OH)₂(s) ⇄ Co⁺²(aq) + 2OH⁻(aq)
So, [Co⁺²] = 1x10⁻⁶M
Ksp = [Co⁺²] *[OH⁻]²
[OH⁻]² = 5.9x10⁻¹⁵/1x10⁻⁶
[OH⁻] = √(5.9x10⁻⁹)
[OH⁻] = 7.6811x10⁻⁵
pOH = -log[OH⁻]
pOH = -log(7.6811x10⁻⁵)
pOH = 4.11
Knowing that pH + pOH = 14
pH = 14 - 4.11
pH = 9.88
An acidic solution is 0.1M in HCl and 0.2 H2so4. volume is equal to no of moles divided by molarity.
number of moles of HCl is 450ml x 0.1 divided by 1000 which is equal to 0.045 moles
volume of HCl is therefore 0.45 divided by 0.16 which is 2.81 litres
Number of moles of H2so4 is 450ml x 0.2 divided by 1000 which is equal to 0.09 moles
volume of H2SO4 IS 0.09 divided by 0.16 which is equal to 0.56 litres
Answer:
Explanation:
For a chemical reaction, the enthalpy of reaction (ΔHrxn) is … ... to increase the temperature of 1 g of a substance by 1°C; its units are thus J/(g•°C). ... Both Equations 12.3.7 and 12.3.8 are under constant pressure (which ... The specific heat of water is 4.184 J/g °C (Table 12.3.1), so to heat 1 g of water by 1 ..
Answer:
Rotational spectroscopy, the dipole moment must change during the transition.
Rotational Raman spectroscopy, molecule must have anisotropic polarizability
Vibrational and electronic spectroscopy, molecule must have permanent dipole moment.
Explanation:
-
For the vibration rotation spectrum to be observed, it is necessary to change the dipole moment during the vibration.
- Raman scattering using an anisotropic crystal gives information about the orientation of the crystal. The polarization of Raman scattering light relative to the crystal, and the polarization of laser light, can be used to determine the orientation of the crystal, provided the crystal structure is known.
